LOCATION JULIN MTEstablished Series
TAXONOMIC CLASS: Fine, smectitic, acid, frigid Aridic Ustorthents
TYPICAL PEDON: Julin silty clay, grassland (colors are for dry soil unless otherwise noted).
A1--0 to 2 inches; gray (10YR 5/1) silty clay, very dark gray (10YR 3/1) moist; moderate very fine granular structure; soft, very friable, sticky and very plastic; many medium, fine, and very fine roots; 5 percent soft shale fragments; 5 percent hard shale fragments; very strongly acid (pH 4.6); clear wavy boundary.
A2--2 to 7 inches; gray (10YR 5/1) silty clay, very dark gray (10YR 3/1) moist; moderate fine granular structure; soft, friable, sticky and very plastic; many very fine, fine, and medium roots; many very fine pores; 5 percent soft shae fragments; 5 percent hard shale fragments; very strongly acid (pH 4.6); clear wavy boundary. (Combined A horizons are 4 to 7 inches thick.)
C1--7 to 25 inches; gray (10YR 5/1) silty clay, very dark gray (10YR 3/1) moist; moderate fine granular structure; soft, friable, sticky and very plastic; many very fine, fine, and medium roots; 40 percent soft shale fragments; 10 percent hard shale fragments; extremely acid (pH 4.4); clear wavy boundary. (7 to 28 inches thick)
C2--25 to 30 inches; gray (5Y 5/1) silty clay, very dark gray (5Y 3/1) moist; massive; very hard, very firm, sticky and plastic; common very fine and fine roots; few medium and coarse roots mainly between plates of shale; 60 percent soft shale fragments; 25 percent hard shale fragments; extremely acid (pH 4.4); clear wavy boundary. (5 to 10 inches thick)
Cr--30 to 60 inches; gray (5Y 5/1) semiconsolidated shale, very dark gray (2.5Y 3/1) moist; extremely hard; sulphur coating on some shale fragments; extremely acid (pH 4.4).
TYPE LOCATION: Fergus County, Montana; about 1,320 feet north and 2,000 feet west of the SE corner of sec. 30, T. 16 N., R. 22 E.
RANGE IN CHARACTERISTICS:
Soil temperature - 44 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 a depth of 20 inches is higher than 41 degrees F.
Depth to bedrock - 20 to 40 inches.
Dark colors (low chroma) are inherited from the acid shale.
A horizons - Hue: 10YR to 5Y
Value: 5 or 6 dry, 3 or 4 moist
Chroma: 1, 2, or 3
Texture: silty clay, clay, or silty clay loam
Clay content: 35 to 60 percent
Rock fragments: 0 to 60 percent shale fragments--5 to 45 percent soft shale, 5 to 15 percent hard shale
Reaction: pH 3.6 to 5.5
C horizons - Hue: 10YR through 5Y
Value: 5 or 6 dry, 3 or 4 moist
Chroma: 1, 2, or 3
Texture: silty clay or clay
Clay content: 40 to 60 percent
Rock fragments: 50 to 85 percent shale fragments--45 to 60 percent soft shale, 5 to 25 percent hard shale
Reaction: pH 3.6 to 5.5
Cr horizon - semiconsolidated shale
Reaction: pH 3.6 to 5.5
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Landform - sedimentary plains and hills.
Elevation - 2,800 to 3,800 feet.
Slope- 2 to 25 percent.
Parent material - alluvium or residuum derived from semiconsolidated acid shale.
Climate - long, cold winters; moist springs; warm summers.
Mean annual air temperature - 42 to 45 degrees F.
Mean annual precipitation - 10 to 14 inches.
Frost-free period - 115 to 135 days.
DRAINAGE AND PERMEABILITY: Well drained; slow permeability.
USE AND VEGETATION: Julin soils are used mainly for rangeland. Potential native vegetation is mainly prairie sandreed, western wheatgrass, big sagebrush, Rosa species, goldenrod, and other perennial forbs.
DISTRIBUTION AND EXTENT: Julin soils are of small extent in central and southeastern Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Fergus County, Montana, 1979.
REMARKS: Soil interpretations records: MT0326, MT8176. Diagnostic horizons and features recognized in this pedon are: an ochric epipedon from the soil surface to a depth of 7 inches (A1 and A2 horizons); a particle-size control section from 10 to 30 inches (C1 and C2 horizons). Julin soils have a frigid temperature regime and an ustic moisture regime bordering on aridic.
Classification changed from Ustic Torriorthents to Aridic Ustorthents in 1994.