LOCATION BLAINCREEK MT
Established Series
Rev. LCB-JB-JCK
12/2013
BLAINCREEK SERIES
The Blaincreek series consists of moderately deep, well drained soils that formed in alluvium, colluvium or residuum derived from igneous and sedimentary bedrock. These soils are on hills, mountain slopes, escarpments, structural benches, and strath terraces. Slopes range from 4 to 70 percent. Mean annual precipitation is about 432 mm, and mean annual temperature is about 6 degrees C.
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Typic Argiustolls
TYPICAL PEDON: Blaincreek gravelly loam, in rangeland (colors are for dry soil unless otherwise noted).
A--0 to 10 cm; brown (7.5YR 5/2) gravelly loam, dark brown (7.5YR 3/2) moist; weak very thin platy structure parting to weak very fine granular; soft, very friable, moderately sticky, slightly plastic; many very fine roots; 25 percent angular and rounded gravel; neutral (pH 6.6); clear smooth boundary. (8 to 18 cm thick)
Bt1--10 to 30 cm; brown (7.5YR 4/2) gravelly clay loam, dark brown (7.5YR 3/2) moist; moderate medium prismatic structure parting to fine and medium subangular blocky; hard, firm, moderately sticky, moderately plastic; common very fine roots; many very fine tubular and interstitial pores; many distinct clay films on faces of peds; 30 percent angular and rounded gravel; neutral (pH 6.8); gradual smooth boundary.
Bt2--30 to 61 cm; brown (7.5YR 5/2) very gravelly loam, brown (7.5YR 4/4) moist; moderate fine and medium subangular blocky structure; hard, firm, moderately sticky, moderately plastic; common very fine roots; many very fine tubular and interstitial pores; many distinct dark brown (7.5YR 3/4) clay films on faces of peds; 50 percent angular and rounded gravel; neutral (pH 7.2); clear smooth boundary. (combined thickness of the Bt horizons is 25 to 89 cm)
R--61 cm; fractured igneous bedrock, few cracks, few very fine roots in some cracks; thin carbonate coats on bottom surfaces of rock fractures.
TYPE LOCATION: Lewis and Clark County, Montana; 549 meters south and 518 meters west of the northeast corner of sec. 16, T. 15 N., R. 4 W.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 3 to 8 degrees C
Mollic epipedon thickness - 18 to 38 cm
Depth to bedrock - 50 to 100 cm
Note: Some pedons have a BC horizon.
A horizon
Hue: 10YR or 7.5YR
Value: 4 or 5 dry; 2 or 3 moist
Chroma: 1 to 3
Texture: loam or silt loam
Clay content: 15 to 25 percent
Rock fragments: 0 to 45 percent--0 to 30 percent gravel or channers, 0 to 20 percent cobbles
Reaction: pH 6.1 to 7.3
Bt1 horizon
Hue: 2.5Y, 10YR, or 7.5YR
Value: 4 or 5 dry; 2 or 3 moist
Chroma: 2 or 3
Texture: clay loam or sandy clay loam
Clay content: 27 to 35 percent
Rock fragments: 30 to 60 percent--20 to 50 percent angular and rounded gravel, 0 to 15 percent angular cobbles
Reaction: pH 6.1 to 7.8
Bt2 horizon
Hue: 10YR or 7.5YR
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2 to 4
Texture: loam, clay loam or sandy clay loam
Clay content: 20 to 35 percent
Rock fragments: 35 to 60 percent--30 to 50 percent angular and rounded gravel, 5 to 25 percent angular cobbles
Reaction: pH 6.1 to 7.8
COMPETING SERIES:
Averett (UT) - have a calcic horizon; are very deep
Bendire (CO) - do not have slightly acid reaction in the subsoil; are not at elevations below 2,438 meters
Borpark (CO) - have a calcic horizon; are very deep
Crackerville (MT) - have a paralithic contact; do not have a lithic contact below 58 cm; do not have gravels more than 7 mm in size
Crampton (MT) - have a paralithic contact; do not have a lithic contact below 100 cm
Curecanti (CO) - are very deep
Ess (AZ) - are very deep
Hilger (MT) - have a calcic horizon; are very deep
Holter (MT) - have a horizon of secondary calcium carbonate accumulation; are very deep
Quincreek (MT) - have a calcic horizon
Sawbuck (MT) - are very deep
Sawicki (MT) - are very deep
Shawmut (MT) - have horizons of calcium carbonate accumulation; are very deep
Wickes (MT) - have a calcic horizon
GEOGRAPHIC SETTING:
Landform: hills, mountain slopes, escarpments, structural benches, and strath terraces
Elevation: 1,220 to 1,890 meters
Slope: 4 to 70 percent
Parent material: alluvium, colluvium, or residuum derived from igneous and sedimentary bedrock
Climate: cold winters; moist springs; warm summers
Mean annual precipitation: 380 to 560 mm
Mean annual air temperature: 2.2 to 7.2 degrees C
Frost-free period: 70 to 110 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Blaincreek soils are used mainly for rangeland. The potential native vegetation is mainly rough fescue, bluebunch wheatgrass, Idaho fescue, Columbia needlegrass, western wheatgrass, forbs, and shrubs.
DISTRIBUTION AND EXTENT: Blaincreek soils are moderately extensive in west-central and southwestern Montana. 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, 1987.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Mollic epipedon - from 0 to 30 cm (A, Bt1 horizons)
Argillic horizon - from 10 to 61 cm (Bt1, Bt2 horizons)
Lithic contact - at 61 cm
Particle-size control section - from 10 to 60 cm (Bt1, Bt2 horizons)
Blaincreek soils have a frigid temperature regime and an ustic moisture regime.
ADDITIONAL DATA: Soil interpretations record - MT1123.
National Cooperative Soil Survey
U.S.A.