LOCATION ARSITE MTEstablished Series
TAXONOMIC CLASS: Clayey, smectitic, nonacid, frigid, shallow Aridic Ustorthents
TYPICAL PEDON: Arsite clay, in grassland (colors are for dry soil unless otherwise noted).
A--0 to 2 inches; light brownish gray (10YR 6/2) sandy clay loam, dark grayish brown (10YR 4/2) moist; strong fine subangular blocky structure with 1/2-inch thick vesicular crust on surface; slightly hard, very friable, slightly sticky and slightly plastic; common fine and very fine roots; neutral (pH 6.6); clear wavy boundary. (1/2 to 3 inches thick)
Cyz1--2 to 6 inches; light brownish gray (10YR 6/2) clay, dark grayish brown (10YR 4/2) moist; strong coarse prismatic structure; hard, firm, sticky and plastic; common fine and very fine roots; common fine masses of gypsum; few very fine seams of other salts; slightly acid (pH 6.3); clear wavy boundary. (4 to 7 inches thick)
Cyz2--6 to 12 inches; light brownish gray (10YR 6/2) clay, very dark grayish brown (10YR 3/2) moist; massive; slightly hard, firm, sticky and plastic; common fine and very fine roots; 30 percent soft shale fragments; common medium masses of gypsum crystals; few fine seams and masses of other salts; few thin iron stains and few small masses of sulfur; moderately acid (pH 6.0); clear wavy boundary. (6 to 11 inches thick)
Cr--12 to 60 inches; grayish brown (10YR 5/2) semiconsolidated shale that crushes to clay, very dark grayish brown (10YR 3/2) moist; common fine seams of gypsum and other salts; common fine iron stains; slightly acid (pH 6.5).
TYPE LOCATION: Carter County, Montana; 2,100 feet south and 550 feet east of the NW corner of sec. 9, T. 2 S., R. 58 E.
RANGE IN CHARACTERISTICS:
Soil temperature - 42 to 47 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 20 inches is 41 degrees F or above.
Depth to Cr horizon - 10 to 20 inches.
The dark colors in the C horizon are lithochromic.
A horizon - Hue: 10YR or 2.5Y
Value: 6 or 7 dry; 4 or 5 moist
Chroma: 2 or 3
Texture: sandy loam, sandy clay loam, or clay
Clay content: 15 to 60 percent
EC: 8 to 16 mmhos/cm
Reaction: pH 6.1 to 7.8
Cyz1 horizon - Hue: 10YR or 2.5Y
Value: 5 or 6 dry; 3 or 4 moist
Chroma: 2 or 3
Texture: clay or silty clay
Clay content: 40 to 60 percent
EC: 12 to 18 mmhos/cm
Reaction: pH 5.6 to 7.3
Cyz2 horizon - Hue: 10YR, 2.5Y or 5Y
Value: 5 or 6 dry; 3, 4, or 5 moist
Chroma: 2 or 3
Texture: silty clay or clay
Clay content: 40 to 60 percent
Coarse fragments: 30 to 50 percent soft shale fragments
EC: 12 to 18 mmhos/cm
Reaction: pH 5.6 to 7.8
COMPETING SERIES:
Neldore (MT) - does not have accumulations of gypsum and other salts within 10 inches of the surface; electrical conductivity is less than 8 throughout the profile.
GEOGRAPHIC SETTING:
Landform - alluvial fans; hills; sedimentary plains.
Elevation - 3,000 to 4,000 feet.
Slope- 0 to 65 percent.
Parent material - residuum or alluvium from semiconsolidated shale.
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 - 100 to 135 days.
DRAINAGE AND PERMEABILITY: Well drained; very slow permeability.
USE AND VEGETATION: Arsite soils are used mainly as rangeland. The potential native vegetation is mainly alkali sacaton, Nuttall alkaligrass, western wheatgrass, Montana wheatgrass, Nuttall saltbush, and low sagebrush. However, the vegetation is very sparse and revegetation of this soil is very difficult.
DISTRIBUTION AND EXTENT: Arsite soils are of small extent in southeastern Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Carter County, Montana, 1992.
REMARKS: Soil interpretations record: MT0643. Diagnostic horizons and features recognized in this pedon are: an ochric epipedon mixed to 7 inches (E, Cyz1 Cyz2 horizons); a particle size control section from the soil surface to 12 inches (E, Cyz1, Cyz2 horizon); a paralithic contact at a depth of 12 inches (Cr horizon). Arisite soils have a frigid temperature regime and an ustic moisture regime that borders on aridic.
Classification changed from Ustic Torriorthents to Aridic Ustorthents in 1993.