LOCATION BIRCHFIELD MTEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Typic Calciaquolls
TYPICAL PEDON: Birchfield mucky peat, in rangeland (Colors are for moist soil unless otherwise noted.)
Oi--0 to 8 inches; very dark brown (10YR 2/2) unrubbed and very dark brown (10YR 2/2) rubbed and pressed fibric material that textures to mucky peat; about 80 percent fiber, about 50 percent rubbed; massive; nonsticky, nonplastic; 40 percent Lycopodium mosses, 50 percent herbaceous and woody; about 10 percent mineral soil; slightly alkaline (pH 7.6 in water); gradual wavy boundary. (6 to 8 inches thick)
Oe--8 to 14 inches; black (10YR 2/1) unrubbed and black (10YR 2/1) rubbed and pressed hemic material that textures to peaty muck (mucky peat?); about 40 percent fiber, about 30 percent rubbed; about 25 percent mineral soil; weak very fine granular structure; nonsticky, nonplastic; slightly alkaline (pH 7.8 in water); clear smooth boundary. (4 to 7 inches thick)
Akg--14 to 20 inches; very dark gray (10YR 3/1) loam, dark gray (10YR 4/1) dry; common medium distinct yellowish brown (10YR 5/4) redox concentrations; weak fine granular structure; slightly hard, friable, moderately sticky, slightly plastic; common fine roots; few fine threads and seams of lime; slightly effervescent; slightly alkaline (pH 7.6); clear wavy boundary. (4 to 7 inches thick)
Bkg1--20 to 25 inches; very dark gray (10YR 3/1) gravelly clay loam, gray (10YR 5/1) dry; common medium distinct yellowish brown (10YR 5/4) and yellowish brown 10YR 5/6) redox concentrations; weak fine subangular blocky structure; hard, friable, moderately sticky, moderately plastic; few very fine roots; common fine threads and seams of lime; 15 percent gravel; strongly effervescent; moderately alkaline (pH 8.0); gradual smooth boundary. (4 to 6 inches thick)
Bkg2--25 to 37 inches; dark gray (10YR 4/1) very gravelly clay loam, gray (10YR 6/1) dry; few fine distinct yellowish brown (10YR 5/4) and yellowish brown (10YR 5/6) redox concentrations; weak fine subangular blocky structure; very hard, firm, moderately sticky, moderately plastic; 5 percent cobbles; 40 percent gravel; disseminated lime, common medium masses of lime; violently effervescent; moderately alkaline (pH 8.0); gradual smooth boundary. (5 to 10 inches thick)
Bkg3--37 to 60 inches; gray (10YR 5/1) extremely gravelly loam, light gray (10YR 7/1) dry; few fine distinct yellowish brown (10YR 5/4) redox concentrations; massive; very hard, firm, moderately sticky, slightly plastic; 10 percent cobbles; 65 percent gravel; common medium masses of lime; violently effervescent; moderately alkaline (pH 8.0).
TYPE LOCATION: Teton County, Montana; 2,300 feet west and 2,300 feet south of the northeast corner of sec. 28, T. 25 N., R. 7 W.
RANGE IN CHARACTERISTICS:
Soil temperature: 42 to 47 degrees F
Thickness of the histic epipedon: 8 to 16 inches
Thickness of the mollic epipedon: 7 to 12 inches (Colors are mollic when mixed to 7 inches if the Akg horizon is less than 7 inches.)
Control section: 10 to 40 inches depth below the Oi epipedon
Depth to seasonal water table: 0 to 12 inches
Soil phases: Peat or mucky peat
Oi horizon
Value: 2 or 3 moist
Chroma: 1 or 2
Fiber content: 75 to 90 percent unrubbed; 45 to 70 percent rubbed
Mineral content: 5 to 20 percent
Reaction: pH 7.4 to 7.8
Oe horizon
Value: 2 or 3 moist
Chroma: 1 or 2
Fiber content: 35 to 60 percent unrubbed; 25 to 35 percent rubbed
Mineral content: 15 to 35 percent
Reaction: pH 7.4 to 7.8
Akg horizon
Hue: 10YR or 2.5Y
Value: 3 or 4 dry; 2 or 3 moist
Chroma: 1 or 2
Texture: Loam or clay loam
Clay content: 20 to 30 percent
Content of rock fragments: 0 to 20 percent gravel
Calcium carbonate equivalent: 10 to 15 percent
Reaction: pH 7.4 to 8.4
Bkg1 horizon
Hue: 10YR or 2.5Y
Value: 4 or 5 dry; 2 or 3 moist
Texture: Loam or clay loam
Clay content: 20 to 35 percent
Content of rock fragments: 5 to 35 percent gravel
Calcium carbonate equivalent: 20 to 30 percent
Reaction: pH 7.9 to 8.4
Bkg2 horizon
Hue: 10YR or 2.5Y
Value: 5 to 7 dry; 4 or 5 moist
Texture: Loam, clay loam, or sandy clay loam
Clay content: 20 to 30 percent
Content of rock fragments: 35 to 60 percent--0 to 10 percent cobbles; 35 to 50 percent gravel
Calcium carbonate equivalent: 25 to 35 percent
Reaction: pH 7.9 to 8.4
Bkg3 or Cg horizon
Hue: 10YR, 2.5Y, 5Y, or N
Value: 6 or 7 dry; 4 or 5 moist
Chroma: 0 to 2
Texture: Loam, clay loam, or sandy loam
Clay content: 10 to 30 percent
Content of rock fragments: 60 to 70 percent--5 to 15 percent cobbles; 55 to 65 percent gravel
Calcium carbonate equivalent: 20 to 35 percent
Reaction: pH 7.9 to 8.4
COMPETING SERIES: None
GEOGRAPHIC SETTING:
Landform: Depressions on alluvial fans, stream terraces, and flood plains
Elevation: 3,800 to 5,800 feet
Slope: 0 to 2 percent
Parent material: Calcareous gravelly alluvium derived mainly from limestone, dolomite, and sandstone
Climate: Long, cold winters; cool, moist springs; warm, dry summers
Mean annual precipitation: 12 to 19 inches
Mean annual temperature: 40 to 45 degrees F
Frost-free period: 90 to 115 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Judith (MT) is well drained and occurs on adjacent higher areas on fans and terraces.
Tetonview (MT) lacks a histic epipedon and is poorly drained.
Windham (MT+WY) is well drained and occur on adjacent higher areas on fans and terraces.
Winginaw (MT) formed in organic materials 16 to 51 inches thick over loamy alluvium.
DRAINAGE AND PERMEABILITY: Very poorly drained; moderately slow permeability
USE AND VEGETATION: Birchfield soils are used mainly for rangeland and wildlife habitat. The Potential native vegetation is mainly northern reedgrass, tall sedges, bulrushes, rushes, willows, and Lycopodium mosses.
DISTRIBUTION AND EXTENT: Birchfield soils are of limited extent in central and western Montana. MLRA 46.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Choteau-Conrad Area; Parts of Teton and Pondera Counties, Montana, 1991; proposed in Teton County, Montana, 1982
REMARKS:
Soil interpretation record: MT0753
Diagnostic horizons and features recognized in this pedon:
histic epipedon 14 inches thick (Oi, Oe horizons)
mollic epipedon 7 inches thick, when mixed (Akg, part of Bkg1 horizons)
calcic horizon from 20 to 60 inches (Bkg1, Bkg2, Bkg3 horizons)
water table at 0 to 12 inches during the growing season
Birchfield soils have a thick 8- to 16-inch surface mantle of fibrous organic material derived mainly from sedges, rushes, and grasses
Birchfield soils have a frigid temperature regime and an aquic moisture regime.