LOCATION MOLLET MTEstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive Ustic Argicryolls
TYPICAL PEDON: Mollet loam, 4 to 15 percent slopes, in rangeland (colors are for dry soil unless otherwise noted).
A1--0 to 7 inches; dark grayish brown (10YR 4/2) loam, very dark brown (10YR 2/2) moist; weak fine granular structure; slightly hard, very friable, nonsticky and nonplastic; many very fine, common fine, and few medium roots; many very fine and fine irregular pores; 5 percent pebbles; moderately acid (pH 5.6); clear wavy boundary.
A2--7 to 12 inches; grayish brown (10YR 5/2) loam, very dark brown (10YR 2/2) moist; weak very fine subangular blocky structure; hard, friable, nonsticky and nonplastic; many very fine, common fine, and few medium roots; few very fine and fine tubular pores; 10 percent pebbles; moderately acid (pH 5.8); abrupt wavy boundary. (Combined thickness of the A horizons is 7 to 16 inches.)
Bt1--12 to 16 inches; brown (10YR 5/3) clay loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common very fine, few fine and medium roots; common very fine and fine tubular pores; common distinct clay films on faces of peds; 10 percent pebbles; moderately acid (pH 6.0); abrupt smooth boundary. (0 to 6 inches thick)
Bt2--16 to 29 inches; light yellowish brown (10YR 6/4) gravelly clay loam, dark yellowish brown (10YR 4/4) moist; moderate medium subangular blocky structure; hard, friable, slightly sticky and moderately plastic; common very fine, few fine and medium roots; common very fine, few fine and medium tubular pores; common distinct clay films on faces of peds; 10 percent pebbles and 5 percent cobbles; moderately acid (pH 6.0); abrupt wavy boundary. (10 to 20 inches thick)
Bt3--29 to 60 inches; light yellowish brown (10YR 6/4) gravelly clay loam, dark yellowish brown (10YR 4/4) moist; strong medium subangular blocky structure; very hard, friable, moderately sticky and moderately plastic; few very fine and fine roots; common very fine, few fine and medium tubular pores; few faint clay films on faces of peds; 10 percent pebbles and 5 percent cobbles; moderately acid (pH 6.0); abrupt wavy boundary.
TYPE LOCATION: Powell County, Montana; 1,100 feet south and 800 feet east of the NW corner of sec. 11, T. 10 N., R. 6 W.
RANGE IN CHARACTERISTICS:
Soil temperature - 36 to 41 degrees F.
Moisture control section - between 4 to 12 inches.
Mollic epipedon thickness - 10 to 16 inches.
Control section - 35 to 50 percent clay.
Rock fragments - 0 to 35 percent.
A horizons - Value: 3 or 4 dry; 2 or 3 moist
Chroma: 1 or 2
Clay content: 20 to 27 percent
Rock fragments: 0 to 35 percent--0 to 10 percent stones or boulders, 0 to 15 percent cobbles, 0 to 20 percent pebbles
Reaction: pH 5.6 to 7.3
Bt1 horizon - Value: 4, 5 or 6 dry; 3, 4 or 5 moist
Chroma: 2 or 3
Texture: clay loam, silty clay loam, or clay
Clay content: 35 to 50 percent
Rock fragments: 0 to 15 percent--0 to 5 percent cobbles, 0 to 10 percent pebbles
Reaction: pH 5.6 to 7.8
Bt2 horizon - Texture: clay loam, clay, or silty clay loam
Clay content: 35 to 50 percent
Rock fragments: 5 to 15 percent--0 to 5 percent cobbles, 5 to 10 percent pebbles
Reaction: pH 5.6 to 7.8
Bt3 horizon - Value: 5 or 6 dry, 4 or 5 moist
Chroma: 2 to 6
Texture: clay loam or clay
Clay content: 35 to 45 percent
Rock fragments: 15 to 35 percent--5 to 10 percent cobbles, 10 to 25 percent pebbles
Reaction: pH 5.6 to 7.8
COMPETING SERIES:
Bangtail (MT) - has a paralithic contact at 20 to 40 inches.
Bridger (MT) - has a horizon of calcium carbonate accumulation.
Duckcreek (MT) - has horizon of secondary carbonate accumulation.
Echard (UT) - developed in volcanic ash materials of weakly cemented ash and soft tuff; high in phosphorus; very slow permeability.
Melville (MT) - has horizon of secondry carbonate accumulation.
Rattler (MT) - has a horizon of calcium carbonate accumulation.
Sevier (UT) - has bedrock at depths of 20 to 40 inches.
GEOGRAPHIC SETTING:
Landform - alluvial fans; stream terraces; mountains.
Elevation - 5,200 to 7,800 feet.
Slope - 2 to 60 percent.
Parent material - colluvium and alluvium derived from fine grained igneous rocks.
Climate - long, cold winters; moist springs; short summers.
Mean annual precipitation - 15 to 23 inches.
Mean annual air temperature - 34 to 39 degrees F.
Frost-free season - 30 to 70 days.
DRAINAGE AND PERMEABILITY: Well drained; slow permeability.
USE AND VEGETATION: Mollet soils are used mainly for rangeland. Native vegetation is mainly rough fescue, needlegrass, mountain brome, Idaho fescue, and tufted hairgrass.
DISTRIBUTION AND EXTENT: Mollet soils are inextensive in southwestern Montana.
MLRA OFFICE RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Powell County, Montana, 1994.
REMARKS: Soil interpretation record: MT1299, MT1300. Diagnostic horizons and features recognized in this pedon are: a mollic epipedon from the surface to 12 inches (A1, A2 horizons); and an argillic horizon from 12 to 60 inches (Bt1, Bt2, Bt3 horizons). Mollet soils have a cryic temperature regime and an ustic moisture regime.