LOCATION CAMBETH MTEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, frigid Aridic Calciustepts
TYPICAL PEDON: Cambeth silt loam, grassland (these are crushed colors and for dry soil unless otherwise noted).
A--0 to 3 inches; brown (10YR 5/3) silt loam, dark brown (10YR 3/3) moist; weak medium subangular block structure parting to weak fine granular; slightly hard, very friable, nonsticky and nonplastic; many fine roots; many fine tubular pores; neutral (pH 7.0); clear smooth boundary. (2 to 4 inches thick)
Bw1--3 to 6 inches; brown (10YR 5/3) silt loam, dark brown (10YR 4/3) moist; weak coarse prismatic structure parting to moderate medium subangular blocky; hard, firm, nonsticky and nonplastic; many fine roots; many fine tubular pores; slightly alkaline (pH 7.4); clear smooth boundary. (0 to 7 inches thick)
Bw2--6 to 11 inches; light yellowish brown (10YR 6/4) silt loam, yellowish brown (10YR 5/4) moist; weak coarse prismatic structure parting to moderate medium angular blocky; hard, firm, slightly sticky and slightly plastic; many fine roots; many fine tubular pores; strongly effervescent; slightly alkaline (pH 7.8); clear smooth boundary. (5 to 10 inches thick)
Bk1--11 to 13 inches; pale yellow (2.5Y 7/4) silt loam, light olive brown (2.5Y 5/4) moist; weak coarse prismatic structure parting to weak medium angular blocky; hard, firm, slightly sticky and slightly plastic; many fine roots; many fine tubular pores; few threads and masses of lime; violently effervescent; strongly alkaline (pH 8.6); gradual smooth boundary.
Bk2--13 to 35 inches; pale yellow (2.5Y 7/4) silt loam, light olive brown (2.5Y 5/4) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; many fine roots; many fine tubular pores; few threads and masses of lime; violently effervescent; strongly alkaline (pH 8.6); gradual smooth boundary. (Combined Bk horizons 6 to 29 inches thick)
Cr--35 to 60 inches; white (10YR 8/1) semiconsolidated sedimentary beds that crush to silty clay loam, light brownish gray (10YR 6/2); common fine roots in cracks; violently effervescent; strongly alkaline (pH 8.6).
TYPE LOCATION: McCone County, Montana; 1,200 feet east and 600 feet north of the SW corner of sec. 36, T. 19 N., R. 43 E.
RANGE IN CHARACTERISTICS:
Soil temperature - 42 to 47 degrees F.
Moisture control section - between 4 and 12 inches.
Control section - 18 to 35 percent clay, with less than 15 percent fine sand and coarser.
Depth to Bk horizon - 10 to 15 inches.
Depth to Cr material - 20 to 40 inches.
Soil phases - noncalcareous--0 to 5 percent calcium carbonate equivalent; calcareous--5 to 10 percent calcium carbonate equivalent
A horizon - Hue: 10YR or 2.5Y
Value: 4, 5, or 6 dry; 3 or 4 moist
Chroma: 2, 3, or 4
Texture: silt loam or loam
Clay content: 18 to 27 percent
Effervescence: none to violently
Calcium carbonate equivalent: 0 to 10 percent
Reaction: pH 6.6 to 8.4.
Bw1 horizon - Hue: 10YR or 2.5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2, 3, or 4
Texture: silt loam, loam or silty clay loam
Clay content: 18 to 35 percent
Effervescence: none to violently
Calcium carbonate equivalent: 0 to 10 percent
Reaction: pH 6.6 to 8.4.
Bw2 horizon - Hue: 10YR or 2.5Y
Value: 5, 6, or 7 dry; 4 or 5 moist
Chroma: 2, 3, or 4
Texture: loam, silt loam, or silty clay loam
Clay content: 18 to 35 percent
Effervescence: slightly to violently
Calcium carbonate equivalent: 0 to 10 percent
Reaction: pH 7.4 to 8.4.
Bk horizon - Hue: 10YR, 2.5Y or 5Y
Value: 5 to 8 dry; 4 to 6 moist
Chroma: 2 to 4
Texture: loam, silt loam, or silty clay loam
Clay content: 18 to 35 percent
Calcium carbonate equivalent: 10 to 20 percent in the upper part and 15 to 25 in the lower part
Effervescence: strongly or violently
Reaction: pH 7.9 to 9.0
This horizon may contain as much as 60 percent soft fragments in the lower part. Accumulations of gypsum may be present in some pedons; accumulations of lime may be absent.
COMPETING SERIES:
Brockway (MT) - does not have a paralithic contact at a depth of 20 to 40 inches.
Neen (MT) - does not have a paralithic contact at a depth of 20 to 40 inches;
has horizons of accumulation of salts; is somewhat poorly drained.
GEOGRAPHIC SETTING:
Landform - sedimentary plains; hills; alluvial fans.
Elevation - 1,900 to 5,200 feet.
Slope- 0 to 45 percent.
Parent material - formed in residuum, colluvium, and alluvium derived from interbedded semiconsolidated loamy and clayey sedimentary beds.
Climate - cool with long, cold winters; moist springs; hot, dry summers.
Mean annual precipitation - 10 to 14 inches.
Mean annual temperature - 40 to 45 degrees F.
Frost-free period - 90 to 135 days.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: These soils are used primarily for dry cropland and for range. The potential native vegetation is western wheatgrass, needleandthread, green needlegrass, little bluestem, forbs, and shrubs.
DISTRIBUTION AND EXTENT: Sedimentary uplands of eastern Montana. Cambeth soils are extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: McCone County, Montana, 1981.
REMARKS: Soil interpretation record: MT0255. Diagnostic horizons and features recognized in this pedon are: ochric epipedon from the soil surface to 7 inches (A, Bw1, Bw2 horizons); cambic horizon from 7 to 11 inches (Bw2 horizon); calcic horizon from 11 to 35 inches (Bk1, Bk2 horizons); particle-size control section from 10 to 35 inches (Bw2, Bk1, Bk2 horizons); paralithic contact at a depth of 35 inches. Cambeth soils have a frigid temperature regime and an ustic moisture regime bordering on aridic.