LOCATION SPANPEAK MT
Established Series
Rev. GAR-JAL
02/2011
SPANPEAK SERIES
The Spanpeak series consists of very deep, well drained soils that formed in colluvium from gniess and schist. These soils are on hills. Slopes are 25 to 60 percent. Mean annual precipitation is about 22 inches, and the mean annual temperature is about 36 degrees F.
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Ustic Argicryolls
TYPICAL PEDON: Spanpeak coarse sandy loam, forested (colors are for dry soil unless otherwise noted).
Oi--0 to 2 inches; forest litter of slightly decomposed needles, twigs and leaves. (1 to 2 inches thick)
A--2 to 16 inches; dark grayish brown (10YR 4/2) coarse sandy loam, very dark gray (10YR 3/1) moist; moderate very fine and fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine and fine, common medium and few coarse roots; many very fine and common fine pores; 5 percent gravel, 5 percent cobbles; neutral (pH 6.6). (10 to 15 inches thick)
BA--16 to 25 inches; brown (10YR 5/3) gravelly coarse sandy loam, dark grayish brown (10YR 4/2) moist; moderate fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; common medium and few fine, very fine and coarse roots; many very fine and common fine and medium pores; 10 percent gravel, 5 percent cobbles; neutral (pH 7.0); clear smooth boundary. (0 to 12 inches thick)
Bt--25 to 33 inches; brown (10YR 5/3) very cobbly sandy clay loam, dark grayish brown (10YR 4/2) moist; moderate medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common medium and few coarse roots; common very fine and fine and few medium pores; few faint clay films on faces of peds and gravel surfaces; 20 percent pebbles, 20 percent cobbles; neutral (pH 7.0); clear smooth boundary. (7 to 25 inches thick)
C--33 to 60 inches; grayish brown (10YR 5/2) very gravelly loamy coarse sand, brown (10YR 4/3) moist; massive, loose, nonsticky and nonplastic; few coarse roots; common very fine, fine and medium pores; 30 percent gravel, 15 percent cobbles; neutral (pH 7.0).
TYPE LOCATION: Gallatin County, Montana; 200 feet south and 600 feet west of the NE corner of section 1, T.4S.,R.3E.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 36 to 40 degrees F.
Mean summer soil temperature - 45 to 47 degrees F.
Moisture control section - between 8 and 24 inches; not dry in all parts for 45 consecutive days.
Mollic epipedon thickness - 10 to 15 inches .
A horizon - Value: 4 or 5 dry; 2 or 3 moist
Chroma: 1 or 2
Clay content: 12 to 18 percent
Rock fragments: 5 to 25 percent-- 5 to 15 percent gravel, 0 to 10 percent cobbles, 0 to 3 percent stones
Reaction: pH 6.1 to 7.3
BA horizon - Value: 5 or 6 dry; 3 or 4 moist
Chroma: 2 to 4
Clay content: 12 to 20 percent
Rock fragments: 10 to 25 percent -- 5 to 15 percent gravel, 5 to 10 percent cobbles.
Reaction: pH 6.1 to 7.3
Bt horizon - Value: 5 or 6 dry; 3 or 4 moist
Chroma: 2 to 4
Clay content: 20 to 30 percent
Rock fragments: 35 to 60 percent -- 20 to 35 percent gravel, 15 to 25 percent cobbles
Reaction: pH 6.1 to 7.3
C horizon - Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2 to 4
Texture: coarse sandy loam or loamy coarse sand
Clay content: 5 to 15 percent
Rock fragments: 35 to 60 percent--20 to 35 percent gravel, 15 to 25 percent cobbles
Reaction: pH 6.1 to 7.3
COMPETING SERIES:
Blaine (MT) - has a lithic contact at 20 to 40 inches.
Bowen (CO) - has a lithic contact at 20 to 40 inches.
Ess (AZ) - formed in materials that have a high content of volcanic ash; are at elevations of over 7200 feet.
Fornor (WY) - has horizon of secondary carbonate accumulation.
Fourmile (CO) - does not have an O horizon; has a lithologic discontinuity at 20 to 40 inches.
Geertsen (UT) - has a lithic contact at 40 to more than 60 inches; formed in material weathered from limestone, shaly limestone or clacareous shale.
Hodden (CO) - has horizons of secondary carbonate accumulation; has mean annual precipitation of 10 to 16 inches; formed in alluvium and glacial outwash.
Hoodle (UT) - has horizon of secondary carbonate accumulation.
Itwo (NV) - has a lithic contact at 20 to 40 inches.
Lagarita (CO) - has horizons of secondary carbonate accumulation.
Libeg (MT) - does not have an O horizon; has Bt horizons 24 to 40 inches thick.
Maciver (MT) - has calcic horizons.
Nathale (WY) - has a lithic contact at 20 to 40 inches; does not have an O horizon.
Nathrop (CO) - has a lithic contact at 20 to 40 inches; has horizons of secondary carbonate accumulation; does not have an O horizon.
Norriston (CO) - has a sandy-skeletal 2C horizon at 20 to 40 inches; has a Bt horizon with 5 to 18 percent clay.
Parkview (CO) - has a paralithic contact at 20 to 40 inches; does not have an O horizon.
Quander (CO) - does not have an O horizon; is at elevation of 7,5oo to 11,600 feet.
Ratiopeak (MT) - has horizon of secondary carbonate accumulation.
Tahquats (ID) - has common uncoated silt particles in the upper Bt horizon.
Teeler (WY) - has horizon of secondary carbonate accumulation; Bt horizon has hue of 7.5YR or redder; does not have an O horizon.
Woodhall (CO) - has a lithic contact at 20 to 40 inches.
GEOGRAPHIC SETTING:
Landform - hills.
Elevation - 5,400 to 7,000 feet.
Slope - 25 to 60 percent.
Parent material - colluvium from gniess and schist.
Climate - long, cold winters; cool, moist springs; short summers.
Mean annual precipitation - 17 to 24 inches.
Mean annual air temperature - 34 to 38 degrees F.
Frost-free period - 50 to 70 days.
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Spanpeak soils are used mainly for woodland, understory grazing and wildlife habitat. Potential native vegetation is mainly Douglas-fir, pinegrass, common snowberry, white spiraea, mallow ninebark, heartleaf arnica and western meadowrue.
DISTRIBUTION AND EXTENT: Spanpeak soils are of small extent in southwestern Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Gallatin County, Montana, 1997.
REMARKS: Soil interpretation record: MT1499. Diagnostic horizons and features recognized in this pedon are: a mollic epipedon from 2 to 16 inches (A horizon); an argillic horizon which is the particle-size control section from 25 to 33 inches (Bt horizon). Spanpeak soils have a cryic temperature regime and an ustic moisture regime.
National Cooperative Soil Survey
U.S.A.