LOCATION SELOW MTEstablished Series
TAXONOMIC CLASS: Fine-silty, illitic, frigid Typic Natrixeralfs
TYPICAL PEDON: Selow silt loam, in pasture (colors are for dry soil unless otherwise noted.)
Ap--0 to 8 inches; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; moderate medium subangular blocky structure; soft, friable, slightly sticky and slightly plastic; many fine roots and common medium roots; many fine and very fine discontinuous tubular pores; slightly alkaline (pH 7.6); abrupt smooth boundary. (6 to 10 inches thick)
Btn-8 to 14 inches; light yellowish brown (10YR 6/4) silty clay loam, yellowish brown (10YR 5/3) moist; weak medium prismatic structure parting to strong fine and medium angular blocky; hard, firm, very sticky and plastic; many fine roots and few medium roots; few very fine discontinuous tubular pores; many prominent clay films on ped faces and in pores; strongly alkaline (pH 8.6); clear smooth boundary. (5 to 10 inches thick)
Btnk--14 to 20 inches; very pale brown (10YR 7/4) silty clay loam, yellowish brown (10YR 5/4) moist; strong medium subangular blocky structure; hard, firm, very sticky and plastic; common fine roots; few faint clay films on faces of peds; common masses of lime; violently effervescent; strongly alkaline (pH 9.0); abrupt smooth boundary. (5 to 15 inches thick)
2Bk--20 to 28 inches; light gray (10YR 7/2) silt loam, light brownish gray (10YR 6/2) moist; massive; soft, very friable, nonsticky and nonplastic; few fine roots; disseminated lime; strongly effervescent; strongly alkaline (pH 9.0); gradual smooth boundary. (0 to 12 inches thick)
2C--28 to 60 inches; light gray (10YR 7/2) very fine sandy loam, light brownish gray (10YR 6/2) moist; massive; soft, very friable, nonsticky and nonplastic; few fine roots; disseminated lime; slightly effervescent; strongly alkaline (pH 8.8).
TYPE LOCATION: Sanders County, Montana; 50 feet south and 300 feet east of the NW corner of Sec. 13, T. 21 N., R. 23 W.
RANGE IN CHARACTERISTICS:
Soil temperature - 43 to 47 degrees.
Moisture control section - between 4 and 12 inches.
Depth to Bk horizon - 12 to 20 inches.
Depth to lithologic discontinuity - 18 to 30 inches.
Some pedons have a Bkn horizon that has faint to distinct varves.
Ap horizon - Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2 or 3
Texture: silt loam or silty clay loam
Clay content: 18 to 35 percent
EC: less than 2 mmhos/cm
SAR: 4 to 13
Reaction: 6.6 to 7.8
When not cultivated this horizon is designated an E.
Btn horizon - Value: 6 or 7 dry; 5 or 6 moist
Chroma: 3 or 4
Clay content: 27 to 35 percent
EC: 1 to 4 mmhos/cm
SAR: 13 to 40
Reaction: 7.9 to 9.0
Btnk horizon - Value: 6 or 7 dry; 5 or 6 moist
Chroma: 3 or 4
Texture: silty clay loam, silty clay or clay
Clay content: 27 to 40 percent
Calcium carbonate equivalent: 5 to 10 percent
EC: 1 to 4 mmhos/cm
SAR: 13 to 40
Reaction: pH 8.5 to 9.6
2Bk horizon - Value: 6 or 7 dry; 5 or 6 moist
Chroma: 2 or 3
Texture: silt loam or very fine sandy loam
Clay content: 0 to 10 percent
Calcium carbonate equivalent: 5 to 10 percent
EC: less than 3 mmhos/cm
SAR: 4 to 30
Reaction: pH 8.5 to 9.6
2C horizon - Value: 6 or 7 dry; 5 or 6 moist
Chroma: 2 or 3
Texture: silt loam, very fine sandy loam, or loamy very fine sand
Clay content: 0 to 10 percent
EC: less than 2 mmhos/cm
SAR: 4 to 25
Reaction: 7.4 to 9.0
COMPETING SERIES:
There are no competing series.
GEOGRAPHIC SETTING:
Landform - dissected lake plains and terraces.
Elevation - 2,500 to 3,100 feet.
Slope- 0 to 15 percent.
Parent material - clayey lacustrine and silty eolian deposits.
Climate - long, cold winters; moist springs; warm summers.
Mean annual precipitation - 10 to 14 inches.
Mean annual air temperature - 41 to 45 degrees F.
Frost-free period - 105 to 125 days.
DRAINAGE AND PERMEABILITY: Well drained; very slow over moderate permeability.
USE AND VEGETATION: These soils are used as irrigated hayland, pasture, and rangeland. The potential vegetation is bluebunch wheatgrass, prairie junegrass, and Sandberg bluegrass.
DISTRIBUTION AND EXTENT: Selow soils are of limited extent in mountain valleys of western Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Lake County, Montana, 1991; proposed in Lake County, Montana, 1987.
REMARKS: Soil interpretation record: MT1112. Diagnostic horizons and features recognized in this pedon are: an ochric epipedon from the surface to 8 inches (Ap horizon); a natric horizon from 8 to 20 inches (Btn, Btnk horizons); accumulation of lime from 14 to 28 inches (Btnk, 2Bk horizons). A particle-size control section from 8 to 14 inches (Btn, Btnk horizons). Selow soils have a frigid temperature regime and a xeric moisture regime that borders on aridic.
LABORATORY DATA: S88MT-089-002