LOCATION DARAS MTEstablished Series
TAXONOMIC CLASS: Ashy, glassy Ustivitrandic Haplocryepts
TYPICAL PEDON: Daras gravelly ashy sandy loam, in forest (colors are for dry soil unless otherwise noted).
Oi--0 to 0.5 inch; partially decomposed needles, twigs and leaves.
A--0.5 to 3 inches; grayish brown (10YR 5/2) gravelly ashy sandy loam, very dark grayish brown (10YR 3/2) moist; moderate medium subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; many very fine and fine and few medium roots; many very fine and fine pores; 20 percent pebbles; strongly acid (pH 5.4); clear wavy boundary. (0 to 4 inches thick)
E--3 to 7 inches; gray (10YR 6/1) very gravelly ashy loamy coarse sand, dark grayish brown (10YR 4/2) moist; moderate medium subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; many very fine and few medium roots; many very fine and fine pores; 10 percent cobbles and 30 percent pebbles; moderately acid (pH 5.8); clear wavy boundary. (2 to 8 inches thick)
Bw--7 to 16 inches; pale brown (10YR 6/3) gravelly ashy sandy loam, dark grayish brown (2.5Y 4/2) moist; moderate medium prismatic structure parting to weak medium subangular blocky; slightly hard, very friable, nonsticky and nonplastic; many very fine and fine roots, few medium and coarse roots; many very fine and fine pores; 20 percent pebbles; slightly acid (pH 6.2); gradual wavy boundary.
BC--16 to 35 inches; light gray (2.5Y 7/2) gravelly ashy coarse sandy loam, olive gray (5Y 4/2) moist, weak coarse prismatic structure; slightly hard, very friable, nonsticky and nonplastic; common very fine and fine roots and few medium and coarse roots; common very fine and fine pores; 20 percent pebbles; slightly acid (pH 6.2); gradual irregular boundary (combined thickness of B horizons is 15 to 40 inches).
C1--35 to 51 inches; light brownish gray (2.5Y 6/2) gravelly ashy coarse sandy loam, olive gray (5Y 4/2) moist; massive; slightly hard, very friable, nonsticky and nonplastic; few very fine and fine roots; few very fine and fine pores; 25 percent pebbles; slightly acid (pH 6.4); gradual irregular boundary.
C2--51 to 60 inches; gray (N 6/) very gravelly ashy coarse sandy loam, olive gray (5Y 4/2) moist; massive; slightly hard, very friable, nonsticky and nonplastic; 5 percent cobbles and 40 percent pebbles; neutral (pH 6.6).
TYPE LOCATION: Deer Lodge County, Montana; 1100 feet north and 1650 feet west of the SE corner of section 16, T. 3 N., R. 11 W.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 32 to 40 degrees F.
Mean summer soil temperature - 40 to 46 degrees F.
Moisture control section - between 8 and 24 inches.
Base saturation - more than 60 percent in one or more horizons between 10 and 30 inches.
Volcanic glass - 30 to 50 percent in the coarse silt and sand fraction.
Acid oxalate Al + 1/2 Fe - .12 to .20 percent
A horizon - Hue: 10YR or 2.5Y
Value: 4 or 5 dry; 3 or 4 moist
Chroma: 2 or 3
Clay content: 10 to 20 percent
Rock fragments: 15 to 35 percent--0 to 15 percent cobbles and stones, 5 to 35 percent pebbles
Reaction: pH 5.1 to 6.0
E horizon - Hue: 10YR, 2.5Y or 5Y
Value: 5, 6 or 7 dry; 4, 5 or 6 moist
Chroma: 1, 2 or 3
Texture: ashy loamy coarse sand, ashy coarse sandy loam, or ashy loam
Clay content: 5 to 18 percent
Rock fragments: 15 to 45 percent--0 to 15 percent cobbles and stones, 15 to 30 percent pebbles
Reaction: pH 5.1 to 6.5
Bw and BC horizons - Hue: 10YR, 2.5Y or 5Y
Value: 5, 6 or 7 dry; 4, 5 or 6 moist
Chroma: 1, 2 or 3
Texture: ashy sandy loam, ashy loam, or ashy coarse sandy loam
Clay content: 8 to 18 percent
Rock fragments: 15 to 35 percent--0 to 5 percent cobbles and stones, 15 to 30 percent pebbles
Reaction: pH 6.1 to 7.3
C horizons - Hue: 2.5Y, 5Y or neutral
Value: 6 or 7 dry; 4, 5 or 6 moist
Chroma: 1 or 2
Texture: ashy sandy loam, ashy coarse sandy loam, ashy loamy coarse sand or ashy loamy sand
Clay content: 5 to 15 percent
Rock fragments: 15 to 60 percent--0 to 15 percent cobbles and stones, 15 to 45 percent pebbles
Reaction: pH 6.1 to 7.3
COMPETING SERIES:
Bendoh (MT) - has more than 18 percent clay in the particle-size control section, has a paralithic contact and a lithic contact at 40 to 60 inches.
Eremis (MT) - has more than 18 percent clay in the particle-size control section.
GEOGRAPHIC SETTING:
Landform- alluvial fans, footslopes, mountains and hills.
Elevation - 6,300 to 6,900 feet.
Slope - 4 to 15 percent.
Parent material - colluvium and alluvium from welded tuff bedrock.
Climate - long, cold winters; cold, moist springs; short, cool summers
Mean annual precipitation - 20 to 30 inches.
Mean annual air temperature - 30 to 38 degrees F.
Frost-free period - 30 to 60 days.
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Well drained, moderate permeability.
USE AND VEGETATION: Daras soils are mainly used for woodland, wildlife habitat and watershed. The potential native vegetation is mainly subalpine fir, lodgepole pine, whitebark pine (at higher elevations), grouse whortleberry, white spiraea, pinegrass, blue huckleberry, elk sedge and heartleaf arnica.
DISTRIBUTION AND EXTENT: Daras soils are of small extent in southwestern Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Deer Lodge County, Montana, 1999.
REMARKS: Soil interpretation record: MT1749. Diagnostic horizons and features recognized in this pedon are: an ochric epipedon from the mineral surface to 7 inches (A and E horizons); a cambic horizon from 7 to 35 inches (Bw and BC horizons); a particle size control section from 10 to 40 inches (Bw, BC and C1 horizons). Daras soils have a cryic temperature regime and an ustic moisture regime bordering on udic.
The 3/2008 description reflects a change in classification from Ashy, glassy Vitrandic Eutrocryepts to Ashy, glassy Ustivitrandic Haploocryepts due to revision of the cryepts great groups and subgroups. The competing series section was not updated and should be reviewed after all the cryepts have been re-classified.