LOCATION HOLTER MT+CO
Established Series
Rev. JAL-EMM
01/2013
HOLTER SERIES
The Holter series consists of very deep, well drained soils that formed in colluvium derived from igneous, argillite, or fine grained sedimentary rock. These soils are on hills and mountains. Slopes are 3 to 60 percent. Mean annual precipitation is about 17 inches, and mean annual temperature is about 43 degrees F.
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.
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. (combined thickness of A horizons is 7 to 16 inches thick)
Bt1--12 to 28 inches; yellowish brown (10YR 5/4) extremely channery clay loam, 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, dry or moist
Clay content: 15 to 25 percent
Rock fragments: 15 to 40 percent--15 to 40 percent gravel, channers, or cobbles; 0 to 5 percent flagstones
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, dry or moist
Texture: loam
Clay content: 18 to 27 percent
Rock fragments: 35 to 65 percent--40 to 60 percent gravel, channers, or cobbles; 0 to 5 percent flagstones
Reaction: pH 5.6 to 7.3
Bt horizons
Hue: 5YR, 7.5YR, or 10YR
Value: 4 to 6 dry; 3 to 5 moist
Chroma: 3 or 4, dry or moist
Texture: loam, clay loam or sandy clay loam
Clay content: 25 to 35 percent
Rock fragments: 40 to 65 percent--40 to 60 percent gravel, channers, or cobbles; 0 to 10 percent flagstones
Reaction: pH 6.1 to 7.3
Bk horizon
Hue: 5YR, 7.5YR, or 10YR
Value: 5 to 7 dry; 4 to 6 moist
Chroma: 2, 3, 4, or 6, dry or moist
Texture: loam or sandy clay loam
Clay content: 10 to 25 percent
Rock fragments: 50 to 70 percent--50 to 75 percent gravel, channers, or cobbles; 5 to 10 percent flagstones
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.4 to 8.4
Some pedons have a Btk horizon.
COMPETING SERIES:
Averett (UT) - is deep to a lithic contact
Bendire (CO) - is moderately deep to a lithic contact
Blaincreek (MT) - is moderately deep to a lithic contact
Borpark (CO) - has calcareous Bt horizons
Crackerville (MT) - is moderately deep to a lithic contact
Crampton (MT) - is moderately deep to a paralithic contact
Curecanti (CO) - does not have a consistent k horizon above a depth of 40 inches
Ess (AZ) - has an O horizon
Hilger (MT) - has a calcic horizon
Quincreek (MT) - is moderately deep to a lithic contact
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
Wickes (MT) - is moderately deep to a lithic contact
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 from igneous, argillite, or fine grained sedimentary 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.
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
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. MLRAs 43B, 44B, and 46.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) 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:
Mollic epipedon - the zone from 0 to 12 inches (A1 and A1 horizons)
Argillic horizon - the zone from 12 to 42 inches (Bt1 and Bt2 horizons)
Particle-size control section - the zone from 12 to 32 inches (the Bt1 and part of the Bt2 horizon)
Holter soils have a frigid soil temperature regime and an ustic moisture regime.
The Holter series should be investigated in the future to verify the ranges of rock fragments in the Bt and Bk horizons. The 1998 OSD listed more than 60 percent in these horizons but the NASIS data did not support fragment ranges that high.
National Cooperative Soil Survey
U.S.A.