LOCATION HASKILLPASS             MT

Tentative Series
Rev. CRS-RJS
01/2023

HASKILLPASS SERIES

The Haskillpass series consists of very deep, well drained soils on moraines. They formed in till with minor amounts of volcanic ash mixed in the surface layers. Permeability is moderate. Slopes are 2 to 35 percent. The average annual air temperature is about 43 degrees F. and average annual precipitation is about 17 inches.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Vitrandic Argiustolls

TYPICAL PEDON: Haskillpass ashy silt loam, in rangeland (Colors are for dry soil unless otherwise noted)

A--0 to 8 inches; dark grayish brown (10YR 4/2) ashy silt loam, very dark brown (10YR 2/2) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and fine roots; common very fine and fine tubular pores; 5 percent gravel; neutral (pH 6.6); clear wavy boundary. (6 to 11 inches thick)

AB--8 to 12 inches; brown (10YR 5/3) ashy silt loam, dark brown (10YR 3/3) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and fine roots; common very fine and fine tubular pores; 5 percent gravel and 5 percent cobbles; neutral (pH 6.8); clear wavy boundary. (0 to 6 inches thick)

Bw--12 to 18 inches; light yellowish brown (10YR 6/4) cobbly silt loam, brown (10YR 4/3) moist; moderate fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and fine roots; common very fine and fine tubular pores; 10 percent gravel and 10 percent cobbles; neutral (pH 7.0); clear wavy boundary. (4 to 10 inches thick)

2E--18 to 29 inches; light gray (2.5Y 7/2) very cobbly silt loam, light brownish gray (2.5Y 6/2) moist; moderate fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and fine and few medium roots; common very fine and fine tubular pores; 20 percent gravel and 15 percent cobbles; neutral (pH 7.2); clear wavy boundary. (6 to 14 inches thick)

2Bt--29 to 43 inches; light yellowish brown (2.5Y 6/3) very cobbly silt loam, light olive brown (2.5Y 5/3) moist; moderate medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; common distinct dark yellowish brown (10YR 4/4) clay films on faces of peds; common very fine and fine and few medium roots; few very fine and fine tubular pores; 25 percent gravel and 15 percent cobbles; slightly alkaline (pH 7.6); clear wavy boundary. (10 to 20 inches thick)

2Bk--43 to 60 inches; pale yellow (2.5Y 7/3) very cobbly silt loam, light olive brown (2.5Y 5/4) moist; weak medium and coarse subangular blocky structure; slightly hard, firm, slightly sticky and slightly plastic; few very fine, fine, and medium roots; few very fine and fine tubular pores; 25 percent gravel and 15 percent cobbles; common fine and medium soft masses of lime; strongly effervescent; moderately alkaline (pH 8.0).

TYPE LOCATION: Flathead County, Montana; 2600 feet north and 50 feet east of the southwest corner of section 17, T. 28 N., R. 26 W. UTM zone 11: Northing 5339445, Easting 653510. NAD 83.

RANGE IN CHARACTERISTICS:

Average annual soil temperature - 42 to 45 degrees F.
Mollic epipedon thickness 7 to 16 inches
Depth to secondary calcium carbonates - 24 to 48 inches

A and AB horizons:
Hue - 10YR dry or moist
Value 3, 4, or 5 dry, 1, 2, or 3 moist
Chroma 1, 2, or 3 dry or moist
Clay content 8 to 18 percent
Bulk density - 1.0 to 1.2 g/cm3
Volcanic glass - 5 to 20 percent
Acid oxalate extractable Al + 1/2Fe - 0.4 to 1.0 percent
Rock fragments: 0 to 20 percent--0 to 10 percent gravels, 0 to 10 percent cobbles, 0 to 5 percent stones
Reaction - pH 6.0 to 6.8

Bw horizon:
Hue - 10YR dry or moist
Value 5 or 6 dry, 4 or 5 moist
Chroma - 3 or 4 dry or moist
Clay content 10 to 18 percent
Bulk density - 1.0 to 1.2 g/cm3
Volcanic glass - 5 to 20 percent
Acid oxalate extractable Al + 1/2Fe - 0.4 to 1.0 percent
Rock fragments: 5 to 25 percent--5 to 15 percent gravel, 0 to 10 percent cobbles, 0 to 5 percent stones
Reaction - pH 6.4 to 7.2

2E horizon:
Hue - 2.5Y or 10YR dry or moist
Value 6, 7 or 8 dry, 5, 6, or 7 moist
Chroma 2 or 3 dry or moist
Texture silt loam or very fine sandy loam
Clay content 5 to 18 percent
Rock fragments: 20 to 40 percent--10 to 20 percent gravel, 10 to 20 percent cobbles, 0 to 5 percent stones
Reaction - pH 6.4 to 7.4

2Bt horizon:
Hue - 2.5Y or 10YR dry or moist
Value 5, 6, or 7 dry, 4, 5, or 6 moist
Chroma 3 or 4 dry or moist
Texture silt loam or silty clay loam
Clay content 20 to 35 percent
Rock fragments: 35 to 60 percent--15 to 25 percent gravel, 10 to 20 percent cobbles, 0 to 15 percent stones
Reaction - pH 6.8 to 7.8

2Bk horizon:
Hue - 2.5Y or 10YR dry or moist
Value 6 or 7 dry, 5 or 6 moist
Chroma 3 or 4 dry or moist
Texture silt loam or very fine sandy loam
Clay content 12 to 27 percent
Calcium carbonate equivalent 2 to 10 percent
Rock fragments: 35 to 60 percent--15 to 25 percent gravels, 10 to 20 percent cobbles, 0 to 15 percent stones
Reaction 7.6 to 8.4 percent

COMPETING SERIES: This is the Macabre series. The Macabre series consists of soils that are moderately deep to a paralithic contact of welded tuff.

GEOGRAPHIC SETTING:
Landform moraines.
Elevation 3400 to 4200 feet.
Slope - 2 to 35 percent.
Parent material volcanic ash over till.
Climate - long, cold winters; moist springs; warm, dry summers.
Mean annual precipitation 15 to 24 inches, much of which falls as snow and spring rain.
Mean annual air temperature - 40 to 46 degrees F.
Frost-free period - 70 to 100 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are Finleypoint, Prospect, and Yeoman soils. Finleypoint soils do not have argillic horizons and are on moraines. Prospect soils are fine-loamy and are on moraines. Yeoman soils are fine-loamy and pachic and are on moraines.

DRAINAGE AND PERMEABILITY: Well drained, moderate permeability.

USE AND VEGETATION: Haskillpass soils are used for rangeland, wildlife habitat, and watershed. The native vegetation is Idaho fescue, bluebunch wheatgrass, prairie junegrass, Richardson needlegrass, western yarrow, lupine, and sticky geranium.

DISTRIBUTION AND EXTENT: Haskillpass soils are of small extent in northwest Montana. MLRA 43A and 44A.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana

SERIES PROPOSED: Flathead County, Montana, 2005. The name is coined from Haskill Pass in Flathead County, Montana.

REMARKS: Diagnostic horizons and features recognized in this pedon are:

Mollic epipedon - 0 to 12 inches (A and AB horizons)
Albic horizon - 18 to 29 inches (2E horizon)
Argillic horizon - 29 to 43 inches (2Bt horizon)
Particle-size control section - 29 to 43 inches (2Bt horizon)

Haskillpass soils have a frigid temperature regime and an ustic moisture regime.

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National Cooperative Soil Survey
U.S.A.