LOCATION BLYTHE MTEstablished Series
TAXONOMIC CLASS: Very-fine, smectitic, frigid Vertic Argiustolls
TYPICAL PEDON: Blythe silt loam, cultivated. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 7 inches; gray (10YR 5/1) silt loam, black (10YR 2/1) moist; strong fine granular structure; hard, very friable, slightly sticky and slightly plastic; many fine roots; many fine pores; slightly acid (pH 6.4); abrupt wavy boundary. (4 to 8 inches thick)
E--7 to 11 inches; light gray (10YR 6/1) silt loam, very dark gray (10YR 3/1) moist; weak thick platy structure parting to moderate very fine blocky; hard, very friable, slightly sticky and slightly plastic; many fine roots; many fine pores; slightly acid (pH 6.4); abrupt smooth boundary. (1 to 5 inches thick)
Bt1--11 to 15 inches; dark grayish brown (10YR 4/2) clay, very dark grayish brown (10YR 3/2) moist; strong medium columnar structure parting to strong medium and fine blocky; hard, firm, moderately sticky and moderately plastic; few fine roots; common fine and very fine pores; light gray (10YR 6/1) coatings of silt and sand on tops and sides of columns; faint continuous clay films on peds; neutral (pH 7.0); clear wavy boundary.
Bt2--15 to 24 inches; dark grayish brown (10YR 5/2) clay, dark grayish brown (10YR 4/2) moist; moderate medium prismatic structure parting to moderate medium and fine blocky; very hard, very firm, moderately sticky and moderately plastic; few fine roots; common fine and very fine pores; faint continuous clay films on peds; neutral (pH 7.0); clear wavy boundary. (Bt horizon is 10 to 20 inches thick)
Bk--24 to 36 inches; grayish brown (2.5Y 5/2) clay, dark grayish brown (2.5Y 4/2) moist; few fine distinct mottles of yellowish brown (10YR 5/6); moderate medium subangular blocky structure; very hard, firm, moderately sticky and moderately plastic; few fine roots; common fine and very fine pores; common medium distinct masses of segregated lime; slightly effervescent; slightly alkaline (pH 7.6); gradual boundary.
Cr1--36 to 43 inches; gray (5Y 5/1) clay shale, dark gray (5Y 4/1) moist; common fine distinct mottles of yellowish brown (10YR 5/6); massive; very hard, very firm, moderately sticky and moderately plastic; slightly effervescent; moderately alkaline (pH 8.0); gradual boundary.
Cr2--43 to 47 inches; platy clay shale.
TYPE LOCATION: Cascade County, Montana; 1,320 feet south and 200 feet west of NE corner of section 31, T.20N., R.32W.
RANGE IN CHARACTERISTICS:
Soil temperature - 41 to 47 degrees F.
Depth to the paralithic contact - 20 to 40 inches.
Mollic epipedon thickness - 7 to 10 inches.
Depth to the Bk horizon - 15 to 30 inches.
Some pedons have slickensides below 20 inches.
Ap horizon - Hue: 2.5Y or 10YR
Value: 3 to 5 dry, 2 or 3 moist
Chroma: 1 or 2
Texture: loam or silt loam
Clay content: 20 to 27 percent
Reaction: pH 6.1 to 7.3
E horizon - Value: 6 or 7 dry, 3 to 5 moist
Chroma: 1 or 2
Texture: loam or silt loam
Clay content: 20 to 27 percent
Reaction: pH 6.1 to 7.3
Bt horizons - Hue: 10YR or 2.5Y
Value: 4 or 5 dry, 3 or 4 moist
Chroma: 2 to 4
Texture: clay or silty clay
Clay content: 60 to 75 percent
Reaction: pH 6.6 to 7.8
Bk horizon - Hue: 10YR or 2.5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2 to 4
Texture: clay or silty clay
Clay content: 60 to 75 percent
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.4 to 8.4
COMPETING SERIES:
Seco (NM) - is very deep.
GEOGRAPHIC SETTING:
Landform - sedimentary uplands
Elevation - 3,600 to 5,000 feet
Slope - 0 to 45 percent
Parent material - material weathered from shale interbedded with siltstone and sandstone
Climate - cool, subhumid, continental
Mean annual precipitation - 14 to 20 inches
Mean annual temperature - 38 to 45 degrees F., mean January temperature about 10 degrees to 26 degrees F., and mean July temperature about 63 degrees to 70 degrees F.
Frost-free period - 105 to 135 days.
DRAINAGE AND PERMEABILITY: Well drained; very slow permeability.
USE AND VEGETATION: The Blythe soils are used mainly for the production of nonirrigated small grains and alfalfa. The native vegetation is green needlegrass, western wheatgrass, bluebunch wheatgrass and Idaho fescue.
DISTRIBUTION AND EXTENT: The Blythe soils are mainly in central Montana, near the mountains. They are of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Judith Basin Area, Montana, 1963.
REMARKS: Diagnostic features and horizons recognized in this pedon are: a mollic epipedon from the surface to 7 inches (Ap horizon); an argillic horizon, which is the particle-size control section from 11 to 24 inches (Bt horizons); accumulation of secondary carbonates from 24 to 36 inches (Bk horizon); and a paralithic contact at 36 inches (Cr1 horizon). Blythe soils have an ustic moisture regime and a frigid temperature regime.