LOCATION PEERLESS MTEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Typic Haplustolls
TYPICAL PEDON: Peerless loam, in grassland. (Colors are for dry soil unless otherwise noted.)
A--0 to 5 inches; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; weak fine and medium granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine roots and few fine roots; 5 percent pebbles; mildly alkaline (pH 7.4); clear smooth boundary. (4 to 8 inches thick)
Bw1--5 to 14 inches; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; moderate medium prismatic structure parting to moderate coarse subangular blocky; slightly hard, very friable, slightly sticky and slightly plastic; common very fine roots and few fine roots; many very fine pores; 5 percent pebbles; mildly alkaline (pH 7.4); clear wavy boundary.
Bw2--14 to 20 inches; pale brown (10YR 6/3) loam, brown (10YR 4/3) moist; moderate coarse prismatic structure; hard, friable, slightly sticky and slightly plastic; common very fine roots and few fine roots; many very fine pores; 5 percent pebbles; strongly effervescent; moderately alkaline (pH 8.2); gradual wavy boundary. (Combined thickness of the Bw horizons is 7 to 16 inches.)
Bk--20 to 27 inches; light gray (10YR 7/2) loam, brown (10YR 5/3) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; common very fine roots; many very fine pores; 10 percent pebbles; common fine soft masses of lime; violently effervescent; strongly alkaline (pH 8.6); clear smooth boundary. (0 to 14 inches thick)
2Ck--27 to 37 inches; pale brown (10YR 6/3) very gravelly sandy clay loam, brown (10YR 5/3) moist; massive; soft, very friable, slightly sticky and nonplastic; few very fine roots; 55 percent pebbles; many distinct lime coatings on pebbles; strongly effervescent; moderately alkaline (pH 8.4); gradual wavy boundary. (5 to 11 inches thick)
2C--37 to 60 inches; light yellowish brown (2.5Y 6/4) very gravelly sandy loam, olive brown (2.5Y 4/4) moist; single grain; loose, nonsticky, and nonplastic; few very fine roots in upper part; 55 percent pebbles; common distinct lime coatings on underside of pebbles; strongly effevescent; moderately alkaline (pH 8.2).
TYPE LOCATION: Prairie County, Montana; 50 feet north and 1,400 feet west of the SE corner of sec. 33, T. 16 N., R. 50 E.
RANGE IN CHARACTERISTICS:
Soil temperature - 42 to 47 degrees F.
Moisture control section - approximately between the depths of 4 and 12 inches
Mollic epipedon thickness - 7 to 16 inches (includes the Bw1 horizon)
Depth to calcic horizon - 11 to 24 inches
Control section - 18 to 27 percent clay and 15 to 35 percent rock fragments
Depth to 2Ck horizon - 22 to 38 inches
A horizon - Value: 4 or 5 dry
Chroma: 2 or 3
Clay content: 15 to 27 percent
Rock fragments: 0 to 10 percent pebbles
Reaction: pH 6.6 to 7.8
Bw1 horizon - Value: 4 or 5 dry
Chroma: 2 or 3
Texture, less than 2 mm: loam or clay loam
Clay content: 18 to 30 percent
Rock fragments: 0 to 10 percent pebbles
EC: less than 2 mmhos/cm
Reaction: pH 7.4 to 8.4
Bw2 horizon - Value: 5 or 6 dry; 3 or 4 moist
Chroma: 2 or 3
Clay content: 18 to 27 percent
Rock fragments: 0 to 15 percent pebbles
EC: less than 2 mmhos/cm
Reaction: pH 7.4 to 8.4
Bk horizon - Hue: 10YR or 2.5Y
Value: 6 or 7 dry; 4 or 5 moist
Chroma: 2, 3, or 4
Clay content: 18 to 27 percent
Rock fragments: 5 to 25 percent--0 to 5 percent cobbles, 5 to 20 percent pebbles
Calcium carbonate equivalent: 20 to 35 percent
EC: less than 4 mmhos/cm
Reaction: pH 7.9 to 9.0
2Ck horizon - Hue: 10YR or 2.5Y
Value: 6 or 7 dry; 4 or 5 moist
Chroma: 2, 3, or 4
Texture, less than 2 mm: loam or sandy clay loam
Clay content: 18 to 27 percent
Rock fragments: 35 to 60 percent--0 to 5 percent cobbles, 35 to 55 percent pebbles
Calcium Carbonate Equivalent: 15 to 20 percent
EC: less than 4 mmhos/cm
Reaction: pH 7.9 to 9.0
2C horizon - Hue: 10YR or 2.5Y
Value: 6 or 7 dry; 4 or 5 moist
Chroma: 2, 3, or 4
Texture, less than 2 mm: loam, sandy loam, or sandy clay loam
Clay content: 10 to 27 percent
Rock fragments: 35 to 60 percent--0 to 5 percent cobbles; 35 to 55 percent pebbles
Calcium Carbonate Equivalent: 8 to 15 percent
EC: less than 4 mmhos/cm
Reaction: pH 7.9 to 9.0
COMPETING SERIES: These are the Amor, Azaar, Coulterg, Max, Minnimaud (t), Quigley, Rottulee, Roundup (t), Shambo, Tansum, and Twin Creek series. The Amor, Minnimaud,and Roundup soils have a paralithic contact at depths of 20 to 40 inches. Azaar soils have hard sandstone at depths of 20 to 40 inches. The Max, Coulterg, and Shambo soils do not have a calcic horizon and do not have more than 35 percent coarse fragments above a depth of 40 inches. Quigley soils do not have more than 35 percent rock fragments above a depth of 40 inches. Tansem soils have no rock fragments throughout the 60-inch profile. Twin Creek soils have hue of 7.5YR and do not have more than 35 percent rock fragments above a depth of 40 inches.
GEOGRAPHIC SETTING: Peerless soils are on fans and terraces. Elevations are 2,400 to 3,400 feet. Slopes are 0 to 4 percent. These soils formed in alluvium. The climate is characterized by long, cold winters; moist springs; and warm summers. Mean annual precipitation is 12 to 16 inches. Mean annual temperature is 40 to 45 degrees F. The frost-free period is 100 to 125 days.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderate permeability.
USE AND VEGETATION: Peerless soils are used mainly as rangeland and for nonirrigated crops. Potential native vegetation is mainly western wheatgrass, bluebunch wheatgrass, green needlegrass, and needleandthread.
DISTRIBUTION AND EXTENT: Peerless soils are of small extent in southeastern Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Prairie County, Montana 1984.
REMARKS: Soil Interpretations Records: MT0875. Diagnostic horizons and features recognized in this pedon are: a noncalcareous mollic epipedon from the soil surface to 14 inches (A, Bw1 horizons); a cambic horizon from 14 to 20 inches (Bw2 horizon); a calcic horizon from 20 to 37 inches (Bk, 2Ck horizons); a particle-size control section from 10 to 40 inches (Bw1, Bw2, Bk, 2Ck, and 2C horizons). Peerless soils have a frigid temperature regime and an ustic moisture regime.