LOCATION CARFALL MTEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Pachic Argiustolls
TYPICAL PEDON: Carfall loam, in rangeland (colors are for dry soil unless otherwise stated).
A1--0 to 7 inches; dark brown (10YR 4/3) loam, very dark brown (10YR 2/2) moist; moderate medium granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine roots; neutral (pH 6.6); clear smooth boundary. (5 to 12 inches thick)
A2--7 to 15 inches; brown (10YR 4/3) loam, very dark grayish brown (10YR 3/2) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; neutral (pH 6.8) clear smooth boundary. (0 to 10 inches)
Bt--15 to 32 inches; brown (10YR 5/3) sandy clay loam, dark brown (10YR 3/3) moist; strong medium and coarse prismatic structure parting to moderate medium subangular blocky; hard, firm, sticky and plastic; many very fine roots; many faint clay films on faces of peds and in pores; neutral (pH 7.0); gradual wavy boundary. (12 to 27 inches)
BC--32 to 60 inches; light brownish gray (10YR 6/2) sandy loam; dark grayish brown (10YR 4/2) moist; massive; slightly hard, very friable, nonsticky and nonplastic; few very fine roots; neutral (pH 7.2).
TYPE LOCATION: Fallon County, Montana; 1,400 feet north and 300 feet east of the SW corner of sec. 10, T.7 N., R.60 E.
RANGE IN CHARACTERISTICS:
Soil temperature - 42 to 47 degrees F.
Moisture control section - between 4 and 12 inches.
Mollic epipedon thickness - 17 to 35 inches (includes part or all of the Bt horizon).
Depth to bedrock - greater than 60 inches.
These soils are noncalcareous throughout.
A horizon - Hue: 10YR or 2.5Y
Value: 4 or 5 dry; 2 or 3 moist
Chroma: 2 or 3
Clay content: 10 to 25 percent
Reaction: pH 6.1 to 7.3
Bt horizons - Hue: 10YR or 2.5Y
Value: 4, 5, or 6 dry; 3, 4, or 5 moist
Chroma: 2, 3, or 4
Texture: sandy clay loam, clay loam, or loam
Clay content: 20 to 35 percent
Reaction: pH 6.1 to 7.3
BC horizon - Hue: 10YR or 2.5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2, 3, or 4
Texture: sandy loam or loamy sand
Clay content: 5 to 20 percent
Reaction: pH 6.1 to 7.3
COMPETING SERIES:
Bowbells (ND) - have horizons of calcium carbonate accumulation above a depth of 40 inches.
Center Creek (UT) - are mottled at depths of 20 to 40 inches; have more than 35 percent rock fragments in the BC horizon.
Chugcreek (WY) - have lithic bedrock at depths of 20 to 40 inches.
Detra (UT) - have hues of 7.5YR and 5YR in the Bt horizons.
Flaxton (ND) - have horizons of calcium carbonate accumulation above a depth of 40 inches.
Herford (AZ) - have horizons of calcium carbonate accumulation above a depth of 40 inches.
Hesperus (CO) - have a BA horizon; have slow permeability.
Pachel (MT) - have horizons of calcium carbonate accumulation above a depth of 40 inches.
Schauson (UT) - are dry in the moisture control section more than half the time the soil temperature is 41 degrees F at a depth of 20 inches.
Todacheene (NM) - have hue of 5YR or 7.5YR throughout the profile.
Weed (CO) - have horizons of calcium carbonate accumulation above a depth of 40 inches.
GEOGRAPHIC SETTING:
Landform - stream terraces; alluvial fans; sedimentary plains; hills.
Elevation - 2,500 to 3,500 feet.
Slope- 0 to 15 percent.
Parent material - noncalcareous alluvium.
Climate - long, cold winters; moist springs; warm summers.
Mean annual precipitation - 10 to 14 inches.
Mean annual temperature - 41 to 45 degrees F.
Frost-free period - 110 to 135 days.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Carfall soils are used for range and nonirrigated crops. The potential native vegetation consists of western wheatgrass, needleandthread, green needlegrass, blue grama, forbs, and shrubs.
DISTRIBUTION AND EXTENT: Southeastern Montana. Carfall soils are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Fallon County, Montana, 1991.
REMARKS: Soil interpretations record: MT1267. Diagnostic horizons and features recognized in this pedon are: a mollic epipedon from 0 to 35 inches (A1, A2, Bt horizons); an argillic horizon from 15 to 32 inches which is the particle-size control section (Bt horizon). Carfall soils have a frigid temperature regime and ustic moisture regime.