LOCATION DOLUS MTEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Aridic Haplustolls
TYPICAL PEDON: Dolus channery loam, in grassland (colors are for dry soil unless otherwise noted.)
A--0 to 8 inches; brown (10YR 5/3) channery loam, dark brown (10YR 3/3) moist; moderate medium granular structure; slightly hard, friable, nonsticky and nonplastic; few medium roots and many fine and very fine roots; many very fine irregular pores; 20 percent channers; neutral (pH 6.8); clear smooth boundary. (6 to 10 inches thick)
Bw--8 to 16 inches; brown (10YR 5/3) very channery loam, dark brown (10YR 4/3) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and moderately plastic; many fine and very fine roots; many very fine irregular pores; 40 percent channers; neutral (pH 7.0); clear smooth boundary. (6 to 18 inches thick)
Bk--16 to 32 inches; light brownish gray (2.5Y 6/2) very channery loam, grayish brown (2.5Y 5/2) moist; weak medium granular structure; slightly hard, firm, slightly sticky and moderately plastic; common fine and very fine roots; common very fine irregular pores; 45 percent channers; continuous faint lime coatings on surface of rock fragments; disseminated lime; violently effervescent; moderately alkaline (pH 8.4); clear smooth boundary. (14 to 18 inches)
Cr--32 to 60 inches; light yellowish brown (2.5Y 6/4) semiconsolidated sandstone and siltstone, light olive brown (2.5Y 5/4) moist.
TYPE LOCATION: Powell County, Montana; about 1,600 feet south and 575 feet west of the NE corner of sec. 9, T. 9 N., R. 9 W.
RANGE IN CHARACTERISTICS:
Soil temperature - 41 to 46 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 F or higher.
Mollic epipedon thickness - 7 to 10 inches.
Depth to Cr horizon - 20 to 40 inches.
A horizon - Chroma: 2 or 3
Clay content - 15 to 25 percent
Rock fragments: 15 to 25 percent--0 to 5 percent cobbles; 15 to 20 percent channers
Reaction: pH 6.6 to 7.8
Bw horizon - Value - 4, 5 or 6 dry; 3 or 4 moist
Chroma: 2, 3, or 4
Clay content: 15 to 27 percent
Rock fragments: 35 to 50 percent--0 to 10 percent flagstones; 35 to 40 percent channers
Calcium carbonate equivalent: 0 to 5 percent
Reaction: pH 6.6 to 8.4
Bk horizon - Hue: 5Y, 2.5Y or 10YR
Value: 5, 6 or 7 dry; 4, 5, or 6 moist
Chroma: 2 or 3
Clay content: 15 to 27 percent
Rock fragments: 40 to 60 percent--0 to 15 percent flagstones; 40 to 45 percent channers
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.4 to 8.4
Cr horizon - semiconsolidated interbedded sandstone or siltstone
COMPETING SERIES:
Bulltop (ND) - has a lithologic discontinuity at 10 to 18 inches.
Frenchcreek (MT) - does not have a paralithic contact.
Sixbeacon (MT) - does not have a paralithic contact.
GEOGRAPHIC SETTING:
Landform - hills; sedimentary plains.
Elevation - 3,600 to 5,400 feet.
Slope - 2 to 45 percent.
Parent material - residuum or colluvium from semiconsolidated interbedded sandstone and siltstone.
Climate - long, cold winters; moist springs and falls; warm, dry summers.
Mean annual precipitation - 10 to 14 inches.
Mean annual temperature - 39 to 44 degrees F.
Frost-free season - 90 to 105 days.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Dolus soils are used mainly for grazing. Potential native vegetation is mainly bluebunch wheatgrass, antelope bitterbrush, Hoods phlox, and other forbs.
DISTRIBUTION AND EXTENT: Dolus soils are of small extent in southwestern Montana. MLRA 43, 44.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Powell County, Montana, 1995.
REMARKS: Soil interpretation record: MT0751. Diagnostic horizons and features recognized in this pedon are: a mollic epipedon from the soil surface to 8 inches (A horizon); a cambic horizon from 8 to 16 inches (Bw horizon); a horizon of secondary carbonate accumulation from 16 to 32 inches (Bk horizon); a paralithic contact at 32 inches (Cr horizon). Dolus soils have a frigid temperature regime and an ustic moisture regime that borders on aridic.