LOCATION TRICART MTEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Aridic Calciustolls
TYPICAL PEDON: Tricart clay loam, rangeland (colors are for dry soil unless otherwise noted).
A1--0 to 1 inch; dark grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; moderate medium and fine granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine and common fine roots; common very fine pores; neutral; (pH 7.3) clear smooth boundary. (1 to 7 inches thick)
A2--1 to 6 inches; brown (10YR 5/3) clay loam, dark brown (10YR 3/3) moist; moderate medium prismatic structure parting to weak medium and fine subangular blocky; slightly hard, friable, slightly sticky and slightly plastic; common very fine and few fine roots; few very fine pores; 5 percent pebbles; neutral; (pH 7.2) clear wavy boundary. (0 to 6 inches thick)
Bk1--6 to 13 inches; light brownish gray (2.5Y 6/2) clay loam, dark grayish brown (2.5Y 4/2) moist; weak medium prismatic structure parting to weak medium and fine subangular blocky; slightly hard, friable, slightly sticky and plastic; common very fine roots; few very fine pores; 10 percent pebbles; common fine and medium masses of lime; strongly effervescent; slightly alkaline; (pH 7.8) gradual wavy boundary. (0 to 8 inches thick)
2Bk2--13 to 25 inches; light gray (10YR 7/2) very gravelly loam, grayish brown (10YR 5/2) moist; weak medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine roots; few very fine pores; 40 percent pebbles; common distinct lime coatings on surface of pebbles; many fine and medium masses of lime; violently effervescent; moderately alkaline, (pH 8.4) gradual wavy boundary. (10 to 30 inches thick)
2Bk3--25 to 60 inches; light gray (10YR 7/2) very gravelly loam, grayish brown (10YR 5/2) moist; weak, medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine roots; 55 percent pebbles; common distinct lime coatings on surface of pebbles; many fine and medium masses of lime; violently effervescent; moderately alkaline. (pH 8.4)
TYPE LOCATION: Carter County, Montana; 2,500 feet north and 500 feet east of the SW corner of sec. 11, T. 5 S., R. 59 E.
RANGE IN CHARACTERISTICS:
Soil temperature - 42 to 47 degrees F.
Moisture control section - between 4 and 12 inches.
Mollic epipedon thickness - 7 to 10 inches.
A1 horizon - Hue: 10YR or 2.5Y
Chroma: 2 or 3
Texture: loam or clay loam
Clay content: 15 to 35 percent
Rock fragments: 0 to 35 percent pebbles
Effervescence: none to violently
Reaction: pH 6.6 to 8.4
A2 horizon - Hue: 10YR or 2.5Y
Chroma: 2 or 3
Texture: loam or clay loam
Clay content: 15 to 35 percent
Rock fragments: 0 to 35 percent pebbles
Effervescence: none to violently
Reaction: pH 6.6 to 8.4
Bk1 horizon - Hue: 10YR or 2.5Y
Value: 6 or 7 dry; 4, 5, or 6 moist
Chroma: 2 or 3
Texture: sandy loam, loam, or clay loam
Clay content: 15 to 35 percent
Rock fragments: 10 to 35 percent pebbles
Calcium carbonate equivalent: 10 to 30 percent
Reaction: pH 7.4 to 8.4
2Bk horizons - Hue: 10YR or 2.5Y
Value: 6 or 7 dry; 5 or 6 moist
Chroma: 2 or 3
Texture: loam or sandy loam
Clay content: 5 to 20 percent
Rock fragments: 35 to 60 percent pebbles
Calcium carbonate equivalent: 15 to 30 percent
Reaction: pH 7.4 to 8.4
COMPETING SERIES:
Tridell (UT) - have hue redder than 10YR; have a horizon of extremely cobbly, extremely gravelly loamy sand, or sand.
Trimad (MT) - have more than 10 percent cobbles throughout the soil; are at elevations greater than 4,500 feet; have a growing season of 70 to 100 days.
Whetrock (UT) - are moderately deep over a paralithic contact of fractured shale.
GEOGRAPHIC SETTING:
Landform - alluvial fans and stream terraces.
Elevation - 3,000 to 4,000 feet.
Slope- 0 to 45 percent.
Parent material - very gravelly alluvium.
Climate - cool with long, cold winters; moist springs; warm summers.
Mean annual precipitation - 10 to 14 inches.
Mean annual temperature - 40 to 45 degrees F.
Frost-free season - 110 to 135 days.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: These soils are used mainly as rangeland. The potential native vegetation is mainly bluebunch wheatgrass, needleandthread, and prairie junegrass.
DISTRIBUTION AND EXTENT: Southeastern Montana. Tricart soils are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Carter County, Montana, 1992.
REMARKS: Soil interpretation record: MT1311. Diagnostic horizons and features recognized in this pedon are: a mollic epipedon (mixed to 7 inches)(A1, A2, and part of Bk1 horizons); a calcic horizon from 13 to 60 inches (2Bk2 and 2Bk3 horizons); a particle-size control section from 10 to 40 inches (Bk1, 2Bk2, and 2Bk3 horizons). Tricart soils have a frigid temperature regime and an ustic moisture regime bordering on aridic.