LOCATION NORBERT MT+WYEstablished Series
TAXONOMIC CLASS: Clayey, smectitic, calcareous, frigid, shallow
Typic Ustorthents
TYPICAL PEDON: Norbert clay, native grassland. (Colors are for dry soil unless otherwise noted)
A--0 to 2 inches; light brownish gray (2.5Y 6/2) clay, dark grayish brown (2.5Y 4/2) moist; moderate medium granular structure; hard, firm, very sticky and very plastic; common fine roots and pores; disseminated lime, strongly effervescent; moderately alkaline (pH 8.3); clear smooth boundary. (1 to 3 inches thick)
Bw1--2 to 6 inches; light brownish gray (2.5Y 6/2) clay, dark grayish brown (2.5Y 4/2) moist; moderate fine and medium blocky structure; very hard, very firm, very sticky and very plastic; common fine roots; few fine pores; disseminated lime; strongly effervescent; moderately alkaline (pH 8.3); clear wavy boundary.
Bw2--6 to 9 inches; light olive gray (5Y 6/2) clay, olive gray (5Y 4/2) moist; massive; very hard, firm, very sticky and very plastic; few fine roots; common fine pores; few partly weathered soft shale chips; disseminated lime; strongly effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (Combined Bw horizons 0 to 7 inches thick)
Bky--9 to 18 inches; olive gray (5Y 5/2) clay, olive gray (5Y 4/2) moist; massive; very hard, firm, very sticky and very plastic; common fine roots; common fine crystals of gypsum; few fine masses of lime; disseminated lime; 5 percent hard shale fragments and 15 percent soft shale fragments; strongly effervescent; moderately alkaline (pH 8.4); gradual wavy boundary. (6 to 10 inches thick)
Cr--18 to 60 inches; olive gray (5Y 5/2) semiconsolidated shale that crushes to a clay texture, olive gray (5Y 4/2) moist; common fine and few medium roots that are in the vertical and horizontal bedding planes; common medium gypsum crystals.
TYPE LOCATION: Big Horn County, Montana; 725 feet south and 75 feet east of W 1/4 corner sec. 1, T.8 S. R. 33 E.
RANGE IN CHARACTERISTICS:
Soil temperature - 42 to 47 degrees F.
Moisture control section - between 4 and 12 inches.
Depth to Cr horizon - 10 to 20 inches.
A horizon - Hue: 2.5Y or 5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 1 or 2
Texture: clay or silty clay
Clay content: 45 to 60 percent
EC: 0 to 4 mmhos/cm
Reaction: pH 7.4 to 8.4
Bw1 horizon - Hue: 2.5Y or 5Y
Value: 4, 5, or 6 dry; 4 or 5 moist
Chroma: 1 or 2
Texture: clay or silty clay
Clay content: 45 to 60 percent
EC: 0 to 4 mmhos/cm
Reaction: pH 7.4 to 8.4
Bw2 or Bk horizon - Hue: 2.5Y or 5Y
Value: 4, 5, or 6 dry; 4 or 5 moist
Chroma: 1 or 2
Texture: clay or silty clay
Clay content: 50 to 60 percent
Rock fragments: 0 to 20 percent shale fragments--0 to 5 percent hard shale, 0 to 15 percent soft shale
EC: 2 to 4 mmhos/cm
Calcium carbonate equivalent: 2 to 12 percent
Reaction: pH 7.4 to 8.4
Bky horizon - Hue: 10YR, 2.5Y or 5Y
Value: 4, 5, or 6 dry; 4 or 5 moist
Chroma: 1 or 2
Texture: clay or silty clay
Clay content: 50 to 60 percent
Rock fragments: 5 to 30 percent shale fragments--0 to 5 percent hard shale, 5 to 25 percent soft shale
EC: 2 to 4 mmhos/cm
Calcium carbonate equivalent: 5 to 15 percent
Gypsum: 1 to 3 percent
Reaction: pH 7.4 to 8.4
COMPETING SERIES:
Ruko (UT) - less than 50 percent clay in the control section.
Wayden (ND) - less than 50 percent clay in the control section.
GEOGRAPHIC SETTING:
Landform - sedimentary plains, hills, and escarpments.
Elevation - 2,500 to 5,600 feet.
Slope- 4 to 70 percent.
Parent material - residuum weathered from semiconsolidated shale mainly of Cretaceous or Tertiary Age.
Climate - cool with long, cold winters; moist springs; warm summers.
Mean annual precipitation - 13 to 19 inches; most of which falls in the spring and early summer.
Mean annual air temperature - 40 to 45 degrees F.
Frost-free period - 90 to 130 days.
DRAINAGE AND PERMEABILITY: Well drained. Very slow permeability. Runoff is high or very high depending on slope.
USE AND VEGETATION: Norbert soils are used mainly for range. Some small areas are used for dryland crops. Potential native vegetation is western wheatgrass, bluebunch wheatgrass, green needlegrass, blue grama, shrubs, and forbs.
DISTRIBUTION AND EXTENT: Norbert soils are extensive in eastern Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Big Horn County (Big Horn Area), Montana; 1970.
REMARKS: Soil interpretation record: MT0276.
Diagnostic horizons and features recognized in this pedon are: ochric epipedon - the zone from the surface of the soil to a depth of 7 inches (after mixing) (A, Bw1 and Bw2 horizons); paralithic contact - at a depth of 18 inches (Cr horizon); particle-size control section - the zone from 10 to 18 inches (By horizon). Norbert soils have a frigid temperature regime and an ustic moisture regime.