LOCATION HOLTER MT+COEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Typic Argiustolls
TYPICAL PEDON: Holter channery loam, grassland (colors are for dry soil unless otherwise noted).
A1--0 to 8 inches; dark grayish brown (10YR 4/2) channery loam, very dark grayish brown (10YR 3/2) moist; moderate very thin platy structure parting to moderate very fine granular; slightly hard, very friable, slightly sticky and slightly plastic; many very fine roots; many very fine tubular and interstitial pores; 20 percent channers; moderately acid (pH 5.8); clear smooth boundary. (5 to 10 inches thick)
A2--8 to 12 inches; brown (10YR 5/3) very channery loam, dark brown (10YR 3/3) moist; moderate fine subangular blocky structure; slightly hard, very friable, moderately sticky and slightly plastic; many very fine and few fine roots; many very fine tubular and interstitial pores; 55 percent channers; moderately acid (pH 5.8); gradual smooth boundary. (2 to 6 inches thick)
Bt1--12 to 28 inches; yellowish brown (10YR 5/4) extremely channery clay loam, dark brown (10YR 4/3) moist; moderate medium and fine subangular blocky structure; slightly hard, friable, moderately sticky and slightly plastic; common very fine and few fine roots; many very fine tubular and interstitial pores; common distinct clay films on faces of peds; 65 percent channers; slightly acid (pH 6.1); gradual smooth boundary.
Bt2--28 to 42 inches; brown (10YR 5/3) extremely channery clay loam, dark yellowish brown (10YR 4/4) moist; moderate medium and fine subangular blocky structure; slightly hard, friable, moderately sticky and slightly plastic; common very fine tubular and interstitial pores; common distinct clay films on faces of peds and bridging sand grains; 65 percent channers; slightly acid (pH 6.2); clear smooth boundary (8 to 18 inches). (Combined thickness of the Bt horizons is 15 to 35 inches.)
Bk--42 to 60 inches; brown (10YR 5/3) extremely channery loam, dark yellowish brown (10YR 4/4) moist; weak medium and fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and few fine roots to 50 inches and few very fine roots below; many very fine tubular and interstitial pores; 60 percent channers, 5 percent flagstones; continuous faint lime casts on undersides of fragments; strongly effervescent; slightly alkaline (pH 7.4).
TYPE LOCATION: Lewis and Clark County, Montana; 700 feet west and 600 feet south of the NE corner of sec. 2, T. 13 N., R. 5 W.
RANGE IN CHARACTERISTICS:
Soil temperature - 42 to 47 degrees F.
Moisture control section - between 4 to 12 inches.
Mollic epipedon thickness - 7 to 15 inches and may include the upper 3 inches of the Bt horizon.
Depth to Bk horizon - 25 to 50 inches.
A1 horizon - Hue: 7.5YR or 10YR
Value: 4 or 5 dry; 2 or 3 moist
Chroma: 2 or 3
Clay content: 15 to 25 percent
Rock fragments: 15 to 35 percent--0 to 15 percent flagstones or stones, 15 to 30 percent channers
Reaction: pH 5.6 to 7.3
A2 horizon - Hue: 5YR, 7.5YR, or 10YR
Value: 4 or 5 dry; 3 moist
Chroma: 2 or 3
Texture: loam
Clay content: 18 to 27 percent
Rock fragments: 40 to 65 percent--0 to 5 percent flagstones, 40 to 60 percent channers
Reaction: pH 5.6 to 7.3
Bt horizons - Hue: 5YR, 7.5YR, or 10YR
Value: 4, 5 or 6 dry; 3, 4 or 5 moist
Chroma; 3 or 4
Texture: loam, clay loam or sandy clay loam
Clay content: 25 to 35 percent
Rock fragments: 60 to 80 percent--5 to 10 percent flagstones, 55 to 75 percent channers
Reaction: pH 6.1 to 7.3
Bk horizon - Hue: 5YR, 7.5YR, or 10YR
Value: 5, 6 or 7 dry; 4, 5, or 6 moist
Chroma: 2, 3, 4, or 6
Texture: loam or sandy clay loam
Clay content: 10 to 25 percent
Rock fragments: 60 to 80 percent--5 to 10 percent flagstones, 55 to 75 percent channers
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.4 to 8.4
COMPETING SERIES:
Bendire (CO) - has a lithic contact at moderate depths.
Blaincreek (MT) - has a lithic contact at moderate depths.
Borpark (CO) - has calcareous Bt horizons.
Crackerville (MT) - has a paralithic contact at moderate depths.
Crampton (MT) - has a paralithic contact at moderate depths.
Curecanti (CO) - does not have a consistent k horizon above a depth of 40 inches.
Harol (UT) - has extremely cobbly loamy sand or extremely cobbly sand C horizons.
Harpole (UT) - does not have a horizon of secondary carbonate accumulation.
Hilger (MT) - has a calcic horizon.
Quincreek (MT) - has a lithic contact at moderate depths.
Sawbuck (MT) - does not have a horizon of carbonate accumulations.
Sawicki (MT) - does not have a horizon of carbonate accumulation.
Shawmut (MT) - has a calcic horizon.
Shirttail (SD) - does not have a horizon of secondary carbonate accumulation.
Wickes (MT) - has a lithic contact at moderate depths.
Widtsoe (UT) - has a calcic horizon that is strongly cemented; has a hue redder than 7.5YR.
GEOGRAPHIC SETTING:
Landform - hills; mountains.
Elevation - 4,000 to 6,000 feet. In Colorado the elevations range from 7,000 to 8,200 feet.
Slope- 3 to 60 percent.
Parent material - colluvium derived sandstone and limestone from igneous and argillite rock.
Climate - long, cold winters; moist springs; warm summers.
Mean annual precipitation - 15 to 19 inches.
Mean annual temperature - 40 to 45 degrees F.
Frost-free period - 70 to 110 days.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Holter soils are used for rangeland. Potential native vegetation is mainly rough fescue, bluebunch wheatgrass, Columbia needlegrass, Idaho fescue, forbs, and shrubs.
DISTRIBUTION AND EXTENT: Central and southwestern Montana and northwestern Colorado. Holter soils are moderately extensive.
MLRA OFFICE RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Lewis and Clark County Area, Montana, 1991; proposed in Lewis and Clark County, Montana, 1979. Holter is the name of a lake in Lewis and Clark County.
REMARKS: Soil interpretations record: MT0379. Diagnostic horizons and features recognized in this pedon are: a mollic epipedon (A horizon); an argillic horizon (Bt) containing over 60 percent rock fragments; and a loamy-skeletal particle-size control section. Holter soils have a frigid soil temperature regime and an ustic moisture regime.