LOCATION BOHNLY MTEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, frigid Typic Endoaquolls
TYPICAL PEDON: Bohnly silt loam, rangeland (colors are for moist soil unless otherwise noted).
A1--0 to 3 inches; very dark brown (10YR 2/2) silt loam, dark grayish brown (10YR 4/2) dry; strong fine and medium granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many fine and medium roots; many fine irregular pores; neutral (pH 6.8); abrupt smooth boundary.
A2--3 to 8 inches; very dark brown (10YR 2/2) silt loam, dark grayish brown (10YR 4/2) dry; moderate medium subangular blocky structure parting to moderate medium granular; slightly hard, friable, slightly sticky and slightly plastic; many fine and medium roots; many fine and medium tubular pores; neutral (pH 6.6); clear wavy boundary. (Combined thickness of the A horizons is 6 to 12 inches)
Bw--8 to 17 inches; grayish brown (10YR 5/2) silt loam, light brownish gray (10YR 6/2) dry; common medium distinct strong brown (7.5YR 4/6) moist redox concentrations; moderate medium subangular blocky structure parting to weak coarse platy; slightly hard, friable, slightly sticky and slightly plastic; many fine roots; many very fine common fine tubular pores; neutral (pH 6.6); clear wavy boundary. (5 to 10 inches thick)
Cg1--17 to 36 inches; grayish brown (10YR 5/2) silt loam, light brownish gray (10YR 6/2) dry; massive; hard, firm, slightly sticky and slightly plastic; common fine roots; many fine tublar pores; many medium prominent strong brown (7.5YR 5/6) redox concentrations and many fine faint gray (10YR 5/1) moist redox depletions; neutral (pH 6.8); clear wavy boundary. (10 to 25 inches thick)
Cg2--36 to 46 inches; grayish brown (10YR 5/2) silty clay loam, brownish gray (10YR 6/2) dry; massive; hard, firm, slightly sticky and slightly plastic; many medium prominent strong brown (7.5YR 5/6) redox concentrations and many fine faint gray (10YR 5/1) moist redox depletions; neutral (pH 6.8); clear wavy boundary. (0 to 15 inches thick)
Cg3--46 to 60 inches; gray (10YR 5/1) fine sandy loam consisting of thin strata of fine sand and silt loam, light gray (10YR 6/1) dry; massive; slightly hard, friable, slightly sticky and slightly plastic; many fine distinct strong brown (7.5YR 4/6) redox concentrations and many fine faint gray (10YR 5/1) moist redox depletions; neutral (pH 6.8).
TYPE LOCATION: Lake County, Montana; 300 feet west and 90 feet north of the SE corner of sec. 13, T. 20 N., R. 20 W.
RANGE IN CHARACTERISTICS:
Soil temperature - 41 to 47 degrees F.
Moisture control section - between 4 and 12 inches.
Mollic epipedon thickness - 7 to 12 inches.
Particle-size control section - less than 15 percent fine sand or coarser.
Depth to water table - 6 to 24 inches.
Some pedons have a 1 to 3 inche thick surface layer of peat or muck.
A1 and A2 horizons - Value: 3, 4, or 5 dry; 2 or 3 moist
Chroma: 1 or 2
Texture: silt loam, loam, or silty clay loam
Clay content: 18 to 32 percent
Reaction: pH 6.6 to 7.8
Bw horizon - Hue: 10YR or 2.5Y
Value: 3, 4, 5, or 6 dry; 2, 3, 4, or 5 moist
Chroma: 1 or 2
Redoximorphic features: 7.5YR 5/6 or 7.5YR 4/6
Texture: silt loam or silty clay loam
Clay content: 18 to 32 percent
Reaction: pH 6.6 to 7.8
Cg1 and Cg2 horizons - Hue 10YR, 2.5Y, or 5Y
Value: 5, 6, or 7 dry; 2, 3, 4 or 5 moist
Chroma: 1 or 2
Redoximorphic features: 7.5YR 5/6, 7.5YR 4/6, 10YR 5/1, or 10YR 4/1
Texture: silt loam or silty clay loam
Clay content: 18 to 32 percent
Reaction: pH 6.6 to 7.8
Cg3 horizon - Hue: 10YR, 2.5Y, or 5Y
Value: 6 or 7 dry; 4, 5, or 6 moist
Redoximorphic features: 7.5YR 5/6, 7.5YR 4/6, 10YR 5/1, or 10YR 4/1
Texture: fine sandy loam consisting of thin strata of fine sand, very fine sand, and silt loam
Clay content: 5 to 15 percent
Rock fragments: 0 to 15 percent--0 to 5 percent cobbles, 0 to 10 percent pebbles
Reaction: pH 6.6 to 7.8
COMPETING SERIES:
There are no competing series.
GEOGRAPHIC SETTING:
Landform - flood plains.
Elevation - 2,500 to 3,500 feet.
Slope- 0 to 2 percent.
Parent material - silty alluvium.
Climate - long, cold winters; moist springs; warm, dry summers.
Mean annual precipitation - 10 to 19 inches.
Mean annual air temperature - 39 to 45 degrees F.
Frost-free period - 70 to 130 days.
DRAINAGE AND PERMEABILITY: Poorly drained; moderate permeability.
USE AND VEGETATION: Bohnly soils are used mainly for rangeland and pastureland. Potential native vegetation is mainly mannagrass, tufted hairgrass, northern reedgrass, and sedges.
DISTRIBUTION AND EXTENT: Bohnly soils are of small extent in mountain valleys of western Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.
SERIES ESTABLISHED: Lake County, Montana, 1991; proposed Lake County, Montana, 1973. Bohnly is a coined name.
REMARKS: Soil interpretation record: MT0041. Diagnostic horizons and features recognized in this pedon are: a mollic epipedon from the soil surface to 8 inches (A1, A2 horizons); a particle-size control section from 10 to 40 inches. Many distinct and prominent low and high chroma redox concentrations and redox depletions from 17 to 60 inches (Cg1, Cg2, Cg3 horizons). Bohnly soils have a frigid temperature regime and an aquic moisture regime.