LOCATION LAMBETH MTEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, calcareous, frigid Aridic Ustorthents
TYPICAL PEDON: Lambeth silt loam, rangeland (colors are for dry soil unless otherwise noted).
A--0 to 4 inches; light yellowish brown (2.5Y 6/4) silt loam, olive brown (2.5Y 4/4) moist; weak thin platy structure parting to weak very fine granular; slightly hard, very friable, slightly sticky and slightly plastic; many fine and very fine roots; many fine and very fine pores; disseminated lime; slightly effervescent; moderately alkaline (pH 8.0); gradual wavy boundary. (2 to 4 inches thick)
By1--4 to 12 inches; light yellowish brown (2.5Y 6/4) silt loam, olive brown (2.5Y 4/4) moist; weak thin and medium platy structure; hard, very friable, slightly sticky and slightly plastic; many very fine roots; many very fine pores; many seams and masses of gypsum; disseminated lime; strongly effervescent; moderately alkaline (pH 8.2); diffuse wavy boundary. (4 to 10 inches thick)
By2--12 to 60 inches; pale yellow (2.5Y 7/4) silt loam with laminations of silty clay loam and very fine sandy loam, light olive brown (2.5Y 5/4) moist; thin and medium platy structure; hard, very friable, slightly sticky and slightly plastic; few very fine roots; few fine and very fine pores; plates or bands are 2 to 5 mm thick; yellowish brown (10YR 5/4) and reddish brown (5YR 3/3) mottles along lamination planes; few fine seams and masses of gypsum; disseminated lime; strongly effervescent; moderately alkaline (pH 8.4).
TYPE LOCATION: Cascade County, Montana; about 520 feet east and 2,780 feet north of the southwest corner of sec. 10, T. 22 N., R. 5 E.
RANGE IN CHARACTERISTICS:
Soil temperature - 42 to 47 degrees F.
Moisture control section - between 4 and 12 inches, dry in all parts between four-tenths and five-tenths of the cumulative days per year when the soil temperature at a depth of 20 inches is 41 degrees or higher.
The bedrock substratum phase of this series will be a new series when recognized in future mapping. It has weakly consolidated sedimentary beds at a depth of 40 inches and deeper.
A horizon - Hue: 10YR, 2.5Y, or 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: 20 to 35 percent
Calcium carbonate equivalent: 1 to 10 percent
Effervescence: slight to violently
Reaction: pH 6.6 to 8.4
By1 and By2 horizon - Hue: 10YR, 2.5Y, or 5Y
Value: 5, 6, or 7 dry; 4, 5, or 6 moist
Chroma: 2, 3, or 4
Texture: silt loam or silty clay loam with thin bands of loam, fine sandy loam, or very fine sandy loam
Clay content: 20 to 35 percent
Gypsum: 1 to 6 percent
Calcium carbonate equivalent: 5 to 15 percent
Effervescence: strongly or violently
Reaction: pH 7.9 to 9.0
Bk or Bky horizons are allowed. The bands are remnants from lacustrine sediments.
COMPETING SERIES:
Antwerp (MT) - has horizons of salt accumulation; does not have relict mottles.
GEOGRAPHIC SETTING:
Landform - alluvial fans, escarpments, hills, and stream terraces.
Elevation - 2,200 to 4,500 feet.
Slopes- 0 to 70 percent.
Parent material - glaciofluvial, glaciolacustrine, or eolian material; or colluvium from semiconsolidated sedimentary bedrock.
Climate - long, cold winters; moist springs; warm summers.
Mean annual precipitation - 10 to 14 inches.
Mean annual temperature - 40 to 45 degrees F.
Frost-free period - 100 to 135 days.
DRAINAGE AND PERMEABILITY: Well drained; moderately slow permeability.
USE AND VEGETATION: Lambeth soils are used mainly as rangeland. A few areas are used for dryland and irrigated crops. Potential native vegetation is mainly bluebunch wheatgrass, western wheatgrass, green needlegrass, and needleandthread.
DISTRIBUTION AND EXTENT: Lambeth soils are of moderate extent in the west-central part of Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Carbon County (Bridger area), Montana, 1971.
REMARKS: Soil interpretations record: MT0107, MT0203. Diagnostic horizons and features recognized in this pedon are: an ochric epipedon from the soil surface to 7 inches (mixed) (A, By1 horizons); horizons with concentrations of gypsum from 4 to 60 inches (By1, By2 horizons); a particle-size control section from 10 to 40 inches (By1, By2 horizons). Lambeth soils have a frigid temperature regime and an ustic moisture regime bordering on aridic.
ADDITIONAL DATA: Laboratory data--S70MT-013-2.