LOCATION WHEATBELT MTEstablished Series
TAXONOMIC CLASS: Very-fine, smectitic, frigid Sodic Epiaquerts
TYPICAL PEDON: Wheatbelt clay, in rangeland (colors are for dry soil unless otherwise noted).
Ag--0 to 2 inches; gray (5Y 5/1) clay, very dark gray (5Y 3/1) moist; strong very coarse granular structure; extremely hard, extremely firm, very sticky and very plastic; few very fine roots; few very fine pores; moderately alkaline (pH 8.4); clear smooth boundary. (1 to 6 inches thick)
Bnssg--2 to 16 inches; gray (5Y 5/1) clay, very dark gray (5Y 3/1) moist; moderate very fine and fine angular blocky structure; extremely hard, extremely firm, very sticky and very plastic; few very fine roots; few very fine pores; common slickensides intersecting at 30 to 45 degrees from horizontal; strongly alkaline (pH 8.8); clear wavy boundary. (4 to 29 inches thick)
Bnssyzg1--16 to 38 inches; gray (5Y 5/1) clay, dark gray (5Y 4/1) moist; moderate fine and medium angular blocky structure; extremely hard, extremely firm, very sticky and very plastic; few very fine pores; common slickensides intersecting at 30 to 45 degrees from horizontal; many fine masses of gypsum and other salts; strongly alkaline (pH 8.6); gradual wavy boundary. (7 to 23 inches thick)
Bnssyzg2--38 to 60 inches; gray (5Y 5/1) clay, dark gray (5Y 4/1) moist; moderate fine and medium angular blocky structure; extremely hard, extremely firm, very sticky and very plastic; few very fine pores; many slickensides intersecting at 30 to 60 degrees from horizontal; common fine masses of gypsum and other salts; strongly alkaline (pH 8.6).
TYPE LOCATION: Hill County, Montana; 2,300 feet north and 2,100 feet west of the SE corner of sec. 17, T. 37 N., R. 13 E.
RANGE IN CHARACTERISTICS:
Soil temperature - 44 to 47 degrees F.
Soil 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 or higher.
Depth to Bnssg horizon - 1 to 30 inches.
Depth to Bnssyzg horizon - 5 to 30 inches.
This soil, when dry, has cracks that are at least 1 cm wide at a depth of 20 inches. A Bng horizon is allowed.
Water table - ponded, +0.5 to 1.0 foot during part of the growing season in most years.
Ag horizon - Value: 5 dry; 2.5, 3, or 4 moist
Clay content: 60 to 85 percent
Electrical conductivity: 2 to 8 mmhos/cm
Sodium adsorption ratio: 4 to 13
Reaction: pH 7.9 to 9.0
Bnssg horizon - Value: 4 or 5 dry; 2.5, 3 or 4 moist
Texture: clay, silty clay
Clay content: 60 to 85 percent
Electrical conductivity: 2 to 8 mmhos/cm
Sodium adsorption ratio: 8 to 30
Reaction: pH 7.9 to 9.0
Bnssyzg horizons - Value: 4 or 5 dry; 2.5, 3, or 4 moist
Texture: clay, silty clay
Clay content: 60 to 85 percent
Electrical conductivity: 8 to 16 mmhos/cm
Sodium adsorption ratio: 13 to 30
Gypsum: 2 to 5 percent
Reaction: pH 7.9 to 9.0
Calcium carbonate equivalent: 0 to 2 percent
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Landform - lake plains.
Elevation - 2,700 to 2,800 feet.
Slope- 0 to 1 percent.
Parent material - glaciolacustrine deposits.
Climate - long, cold winters; moist springs; warm summers.
Mean annual precipitation - 10 to 14 inches, most of which falls during spring and early summer.
Mean annual air temperature - 40 to 45 degrees F.
Frost-free period - 100 to 120 days.
DRAINAGE AND PERMEABILITY: Poorly drained; very slow permeability.
USE AND VEGETATION: Wheatbelt soils are used as rangeland. The potential plant community is western wheatgrass, inland saltgrass, alkali sacaton, greasewood, and gardner saltbush.
DISTRIBUTION AND EXTENT: Wheatbelt soils are of small extent in north-central Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Hill County, Montana, 1994; proposed in Hill County, Montana, 1992. Wheatbelt is the name of an early Hill County community.
REMARKS: Soil interpretation record: MT1353.
The diagnostic horizon and features recognized in this pedon are: ochric epipedon - from the surface to 7 inches (mixed Ag, Bnssg horizons); slickensides - from 2 to 60 inches (Bnssg, Bnssyzg1, Bnssyzg2 horizons); particle-size control section - from 10 to 40 inches. Wheatbelt soils have a frigid temperature regime and aquic conditions that border on aridic.
ADDITIONAL DATA: Laboratory information--S91MT-041-8.