LOCATION QUAST MT
Established Series
Rev. RJS/JMS/RJS
07/2013
QUAST SERIES
The Quast series consists of very deep, well drained soils that formed in material derived from eolian deposits and alluvium, outwash or colluvium. These soils are on fan remnants, eroded fan remnants, outwash terraces, and hills. Slopes are 2 to 45 percent. Mean annual precipitation is about 380 mm, and mean annual temperature is about 6 degrees C.
TAXONOMIC CLASS: Coarse-silty, mixed, superactive, frigid Typic Haplustolls
TYPICAL PEDON: Quast silt loam, in rangeland (colors are for dry soil unless otherwise noted).
A--0 to 30 cm; dark grayish brown (10YR 4/2) silt loam, very dark brown (10YR 2/2) moist; moderate medium granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine irregular pores; neutral (pH 7.2); abrupt smooth boundary. (25 to 38 cm thick)
Bw1--30 to 64 cm; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; moderate medium subangular blocky structure; soft, friable, slightly sticky and slightly plastic; common very fine and fine roots; common very fine tubular pores; neutral (pH 7.0); gradual smooth boundary.
Bw2--64 to 89 cm; light yellowish brown (10YR 6/4) very fine sandy loam, dark yellowish brown (10YR 4/4) moist; weak medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; few fine and very fine roots; common very fine tubular pores; neutral (pH 7.0); clear wavy boundary. (combined thickness of Bw horizons is 15 to 75 cm)
Bk--89 to 114 cm; light yellowish brown (10YR 6/4) silt loam, dark yellowish brown (10YR 4/4) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; few very fine and fine roots; few very fine tubular pores; finely disseminated carbonates and common fine carbonate masses; strongly effervescent; moderately alkaline (pH 8.0); gradual wavy boundary. (14 to 38 cm thick)
BCk--114 to 152 cm; light yellowish brown (10YR 6/4) fine sandy loam, dark yellowish brown (10YR 4/4) moist; massive; soft, very friable, nonsticky and nonplastic; few very fine and fine roots; few very fine tubular pores; finely disseminated carbonates and common fine carbonate masses; prominent carbonate coats on the bottom surfaces of rock fragments; 5 percent gravel; violently effervescent; moderately alkaline (pH 8.2).
TYPE LOCATION: Ravalli County, Montana; 870 feet north and 2,575 feet west of the SE corner of section 10, T8N, R19W; USGS Corley Gulch, Montana topographic quadrangle; North American Datum 27, zone 12, UTM 272942 meters E, 5149216 meters N.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 5 to 8 degrees C
Mollic epipedon thickness - 25 to 38 cm
Depth to cambic horizon - 25 to 38 cm
Depth to horizon of secondary calcium carbonate accumulation - 40 to 100 cm
Depth to calcic horizon - 100 to 114 cm
Some pedons have a Bk2 horizon in place of the BCk horizon.
A horizon
Hue: 10YR
Value: 3, 4 or 5 dry, 2 or 3 moist
Chroma: 2 or 3
Texture: silt loam, loam or very fine sandy loam
Clay content: 12 to 24 percent
Rock fragments: 0 to 15 percent--0 to 5 percent gravel, 0 to 5 percent cobbles, 0 to 5 percent stones
Reaction: pH 6.6 to 7.3
Bw horizons
Hue: 10YR or 2.5Y
Value: 5 or 6 dry; 3 or 4 moist
Chroma: 2, 3, or 4
Texture: silt loam or very fine sandy loam
Clay content: 12 to 18 percent
Rock fragments: 0 to 5 percent gravel
Reaction: pH 6.6 to 7.6
Bk horizon
Hue: 10YR or 2.5Y
Value: 6, 7, or 8 dry; 4, 5, or 6 moist
Chroma: 2, 3, or 4
Texture: silt loam or very fine sandy loam
Clay content: 10 to 18 percent
Rock fragments: 0 to 5 percent gravel
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 8.1 to 8.4
BCk (or Bk2) horizon
Hue: 10YR or 2.5Y
Value: 6, 7, or 8 dry; 4, 5, or 6 moist
Chroma: 2, 3, or 4
Texture: fine sandy loam, very fine sandy loam or loamy fine sand
Clay content: 5 to 18 percent
Rock fragments: 0 to 15 percent gravel
Calcium carbonate equivalent: 5 to 18 percent
Reaction: pH 8.1 to 8.4
COMPETING SERIES:
Linton (ND) - do not have a calcic horizon; do not have textures with more than 52 percent sand in the particle-size control section
GEOGRAPHIC SETTING:
Landform - fan remnants, eroded fan remnants, outwash terraces, and hills
Elevation - 1,025 to 1,905 meters
Slope - 2 to 45 percent
Parent material - eolian deposits and alluvium, outwash, or colluvium
Climate - long cold winters; moist springs; warm summers
Mean annual precipitation - 330 to 559 mm; evenly distributed throughout the year
Mean annual temperature - 4 to 7 degrees C
Frost-free period - 70 to 120 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Well drained; moderate to moderately rapid permeability.
USE AND VEGETATION: Quast soils are used as rangeland and pasture. Native vegetation is mainly bluebunch wheatgrass, prairie Junegrass, Sandberg bluegrass, forbs, and big sagebrush.
DISTRIBUTION AND EXTENT: Quast soils are of small extent in western Montana mountains and valleys. MLRA 43B and 44A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Bitterroot Valley Area, Montana, 2013; proposed in Ravalli County, Montana, 2004.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - from 0 to 30 cm (A horizon)
Cambic horizon - from 30 to 89 cm (Bw1, Bw2 horizons)
Horizon of secondary calcium carbonate accumulation - 89 to 114 cm (Bk horizon)
Calcic horizon - 114 to 152 cm (BCk horizon)
Particle-size control section - 25 to 100 cm (part of the A, Bw1, Bw2, and part of the Bk horizons)
Quast soils have a frigid temperature regime and an ustic moisture regime.
National Cooperative Soil Survey
U.S.A.