LOCATION FORELEFT MTEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Aridic Haplustalfs
TYPICAL PEDON: Foreleft loam, in rangeland (colors are for dry soil unless otherwise noted).
A--0 to 4 inches; pale brown (10YR 6/3) loam, dark brown (10YR 3/3) moist; moderate fine granular structure; soft, very friable, slightly sticky and slightly plastic; common fine and very fine roots; common very fine tubular pores; slightly alkaline (pH 7.4); clear smooth boundary. (3 to 6 inches thick)
Bt1--4 to 7 inches; brown (10YR 5/3) clay loam, dark brown (10YR 3/3) moist; moderate medium prismatic structure parting to strong medium angular blocky; hard, friable, slightly sticky and plastic; common fine and very fine roots; common very fine and few fine tubular pores; few faint clay films on faces of peds; slightly alkaline (pH 7.6); clear smooth boundary.
Bt2--7 to 16 inches; yellowish brown (10YR 5/4) clay loam, brown (10YR 4/3) moist; strong medium prismatic structure parting to strong coarse subangular blocky; hard, friable, slightly sticky and plastic; common fine and very fine roots; common very fine tubular pores; continuous distinct clay films on faces of peds and in pores; moderately alkaline (pH 8.0); gradual smooth boundary. (Combined thickness of Bt horizons is 8 to 16 inches)
Btk--16 to 21 inches; light yellowish brown (10YR 6/4) loam, dark yellowish brown (10YR 4/4) moist; moderate medium prismatic structure parting to moderate coarse subangular blocky; hard, friable, slightly sticky and slightly plastic; common very fine roots; common very fine tubular pores; common distinct clay films on faces of peds and in pores; few fine masses of lime; slightly effervescent; moderately alkaline (pH 8.0); gradual wavy boundary. (0 to 8 inches thick)
Bk1--21 to 51 inches; light yellowish brown (2.5Y 6/4) loam, light olive brown (2.5Y 5/4) moist; moderate coarse prismatic structure; slightly hard, very friable, nonsticky and slightly plastic; common very fine roots; few very fine tubular pores; common medium masses of lime; violently effervescent; moderately alkaline (pH 8.2); diffuse wavy boundary. (10 to 40 inches thick)
Bk2--51 to 60 inches; light yellowish brown (2.5Y 6/4) silt loam, olive brown (2.5Y 4/4) moist; weak coarse prismatic structure; hard, friable, slightly sticky and plastic; few very fine tubular pores; common fine and medium masses of lime; violently effervescent; strongly alkaline (pH 8.6).
TYPE LOCATION: Custer County, Montana; 2,500 feet east and 500 feet north of the SW corner of sec. 28, T. 2 N., R. 45 E.
RANGE IN CHARACTERISTICS:
Soil temperature - 44 to 47 degrees F.
Depth to Btk or Bk horizon - 11 to 22 inches.
Percent rock fragments - 0 to 5 percent.
A horizon - Hue: 2.5Y or 10YR
Value: 5, 6, or 7 dry; 3, 4, or 5 moist
Chroma: 2 or 3
Texture: loam or silt loam
Clay content: 15 to 25 percent
Reaction: pH 6.6 to 7.8
Bt horizons - Hue: 2.5Y or 10YR
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2, 3, or 4
Clay content: 27 to 35 percent
Reaction: pH 6.6 to 8.4
Btk and Bk horizons - Hue: 2.5Y or 10YR
Value: 5, 6, or 7 dry; 4 or 5 moist
Chroma: 2, 3, or 4
Texture: loam, silt loam, or clay loam
Clay content: 18 to 30 percent
Calcium carbonate equivalent: 5 to 15 percent
Electrical conductivity: 0 to 2 mmhos/cm
Reaction: pH 7.9 to 9.0
COMPETING SERIES:
Alderon (WY) - has a paralithic contact at depths of 20 to 40 inches.
Allens Park (CO) - has lithic bedrock at depths of 20 to 40 inches; has mixed B/E horizons; has O horizons more than 1-inch thick.
Bayerton (WY) - has mixed A/B horizons; has lithic sandstone bedrock at depths of 20 to 40 inches.
Bondoe (MT) - is loamy-skeletal below the argillic horizon; has 15 to 35 percent channers in the argillic horizon.
Bonfri (MT) - has a paralithic contact at 20 to 40 inches.
Elbeth (CO) - has loamy sand E horizons; does not have a horizon of secondary calcium carbonate accumulation.
Elmark (MT) - has a lithic contact at a depth of 23 to 40 inches.
Fairport (MI) - has hue of 7.5YR and redder throughout the soil; has a lithic contact of limestone at depths of 20 to 40 inches.
Ferball (MT) - is calcareous to the surface; has hues of 7.5YR and redder throughout the soil.
Gateson (WY) - has a paralithic contact at depths of 20 to 40 inches.
Haugan (MT) - has argillic horizons 20 to 41 inches thick; has a horizon of secondary calcium carbonate accumulation with 25 to 30 percent rock fragments; has O and E horizons; has hue of 7.5YR and redder in the argillic horizon.
Lakoa (SD) - has mixed B & A horizons; does not have a horizon of secondary calcium carbonate accumulation.
Lengby (MN) - has medium acid to neutral E horizons that are loamy sand; has stratified C horizons that are mainly coarse-loamy.
Lumpgulch (MT) - does not have a horizon of secondary calcium carbonate accumulation; has a lithic contact of granite above a depth of 60 inches.
Nebish (MN) - has skeletans in the upper 8 inches of the argillic horizon; does not have a horizon of secondary carbonate accumulation.
Onaway (MI) - has O, E, Bs, and mixed B/E horizons; formed in materials having volcanic ash.
Plome (CO) - has hues redder than 7.5YR throughout; has mixed A and B horizons; formed in arkose material.
Regnaps (WY) - has a paralithic contact at 20 to 40 inches.
Rule (CO) - has hue redder than 5YR in the argillic horizon; has mixed A/B horizons; has lithic bedrock at depths of 20 to 40 inches.
Snellman (MN) - has moderately acid or slightly acid argillic horizons that are 6 to 18 inches thick.
GEOGRAPHIC SETTING:
Landform - sedimentary plains; alluvial fans; stream terraces.
Elevation - 2,240 to 5,000 feet.
Slope- 0 to 15 percent.
Parent material - alluvium.
Climate - long, cold winters; moist springs; warm summers.
Mean annual air temperature - 42 to 45 degrees F.
Mean annual precipitation - 11 to 16 inches.
Frost-free period - 105 to 135 days.
GEOGRAPHICALLY ASSOCIATED SOILS:
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Foreleft soils are used mainly for rangeland. Some areas are used for nonirrigated cropland. Potential native vegetation is mainly bluebunch wheatgrass, western wheatgrass, needleandthread, blue grama, and green needlegrass.
DISTRIBUTION AND EXTENT: Foreleft soils are of small extent. They are limited to the sedimentary plains of eastern Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Custer County, Montana; 1995.
REMARKS: Soil interpretation record: MT1471. Diagnostic horizons and features recognized in this pedon are: an ochric epipedon from the soil surface to 4 inches (A horizon); an argillic horizon from 4 to 12 inches that is the particle-size control section (Bt1, Bt2, Btk horizons); horizons of secondary carbonate accumulation from 21 to 60 inches (Bk1, Bk2 horizons); Foreleft soils have a frigid temperature regime and an ustic moisture regime that borders on aridic.