LOCATION NOBE MTEstablished Series
TAXONOMIC CLASS: Fine, smectitic, calcareous, frigid Torrertic Ustorthents
TYPICAL PEDON: Nobe silty clay, grassland (colors are for dry soil unless otherwise noted).
E--0 to 1 inch; light brownish gray (2.5Y 6/2) loam, dark grayish brown (2.5Y 4/2) moist; vesicular crust in upper part and weak very thin platy structure in lower part; slightly hard, friable, slightly sticky and nonplastic; common fine and very fine and few medium roots; common fine and very fine pores; neutral (pH 7.2); abrupt wavy boundary. (1 to 2 inches thick)
Bw--1 to 4 inches; grayish brown (2.5Y 5/2) silty clay, dark grayish brown (2.5Y 4/2) moist; strong fine and medium columnar structure parting to moderate fine and very fine subangular blocky; hard, firm, sticky and very plastic; common very fine and few medium roots; common fine and very fine pores; slightly alkaline (pH 7.6); clear wavy boundary. (0 to 3 inches thick)
By--4 to 9 inches; grayish brown (2.5Y 5/2) silty clay, dark grayish brown (2.5Y 4/2) moist; strong very fine subangular blocky structure; hard, friable, sticky and very plastic; common fine and very fine roots; common fine and very fine pores; many fine threads and masses of gypsum; slightly effervescent; strongly alkaline (pH 8.8); gradual wavy boundary. (0 to 12 inches thick)
Byz1--9 to 25 inches; grayish brown (2.5Y 5/2) silty clay, dark grayish brown (2.5Y 4/2) moist; granular structure (flocculation caused by soluble salts); hard, friable, sticky and plastic; few fine and very fine roots; common fine and very fine pores; many threads and masses of gypsum and other soluble salts; strongly effervescent; strongly alkaline (pH 9.0); diffuse smooth boundary. (8 to 20 inches thick)
Byz2--25 to 66 inches; light brownish gray (2.5Y 6/2) stratified silty clay loam and silty clay, dark grayish brown (2.5Y 4/2) moist; massive; hard, firm, sticky and plastic; few fine and very fine roots; common very fine pores; common threads and masses of gypsum and other salts; soil is moist in this horizon; slightly effervescent; strongly alkaline (pH 9.0).
TYPE LOCATION: Cascade County, Montana; 50 feet east and 200 feet south of NW corner of sec. 22, T. 22 N., R. 1 W.
RANGE IN CHARACTERISTICS:
Soil temperature - 42 to 47 degrees F.
Moisture control section - between 4 to 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 F.
Depth to Byz horizon - 4 to 16 inches.
Depth to saturated zone - 24 to 42 inches for 1 to 4 months in the spring. The soil is moist below 42 inches when not saturated or frozen.
E horizon - Hue: 10YR, 2.5Y, or 5Y
Value: 5, 6, or 7 dry; 3, 4, or 5 moist
Chroma: 2 or 3
Texture: loam, clay loam, silty clay loam, silty clay, or clay
Clay content: 20 to 50 percent
EC: 4 to 8 mmhos/cm
SAR: 0 to 13
Calcium carbonate equivalent: 1 to 5 percent
Reaction: pH 6.6 to 8.4
Bw, Bt horizons - Hue: 10YR, 2.5Y, or 5Y
Value: 5, 6, or 7 dry; 4, 5, or 6 moist
Chroma: 2 or 3
Texture: clay, silty clay, or silty clay loam
Clay content: 27 to 50 percent
EC: 4 to 8 mmhos/cm
SAR: 0 to 30
Calcium carbonate equivalent: 1 to 5 percent
Reaction: pH 6.6 to 8.4
This horizon in some areas is recognized as having characteristics of an argillic or cambic horizon but does not meet the minimum requirements of thickness for either one.
By, Byz1 horizons - Hue: 10YR, 2.5Y, or 5Y
Value: 5, 6, or 7 dry; 4, 5, or 6 moist
Chroma: 2 or 3
Texture: clay, silty clay, or silty clay loam
Clay content: 35 to 60 percent
EC: 16 to 30 mmhos/cm
Gypsum: 1 to 6 percent
SAR: 13 to 40 percent
Calcium carbonate equivalent: 1 to 5 percent
Reaction: pH 7.9 to 10.0
Byz2 horizon - Hue: 10YR, 2.5Y, or 5Y
Value: 5, 6, or 7 dry; 4, 5, or 6 moist
Chroma: 2 or 3
Textures: clay, silty clay, or silty clay loam that is stratified with loam, clay loam, and silt loam
Clay content: 35 to 60 percent
EC: 16 to 30 mmhos/cm
Gypsum: 1 to 6
SAR: 13 to 70
Calcium carbonate equivalent: 1 to 5 percent
Reaction: pH 7.9 to 10.0
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Landform - alluvial fans; stream terraces; floodplains, drainageways.
Elevation - 2,000 to 4,500 feet.
Slope- 0 to 15 percent.
Parent material - clayey alluvium derived locally from sedimentary bedrock and glaciofluvial deposits.
Climate - cool with long, cold winters; moist springs; warm summers.
Mean annual precipitation - 10 to 19 inches, more than 70 percent of which falls in spring and early summer.
Mean annual air temperature - 40 to 45 degrees F.
Frost-free period - 100 to 135 days.
DRAINAGE AND PERMEABILITY: Moderately well drained; very slow permeability. Soil is saturated within 60 inches during the spring.
USE AND VEGETATION: Nobe soils are used mainly for grassland but a few small areas are cultivated along with other soils. Potential native vegetation is inland saltgrass, alkali grass, western wheatgrass, and greasewood.
DISTRIBUTION AND EXTENT: Nobe series are of moderate extent and widely distributed throughout Montana and adjacent areas of North Dakota and South Dakota.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Big Horn County (Big Horn Area), Montana; 1970.
REMARKS: Soil interpretation record: MT0014, MT0472. Diagnostic horizons and features recognized in this pedon are:
a.vesicular surface crust of 1/2-inch thick (E horizon); an ochric epipedon from the soil surface to 7 inches (mixed)(E, Bw, By horizons); a horizon of gypsum accumulation from 4 to 9 inches (By horizon); accumulation of gypsum and other salts from 9 to 60 inches (Byz1, Byz2 horizons); a particle-size control section from 10 to 40 inches (Byz1, Byz2 horizons). Nobe soils have a frigid temperature regime and an ustic moisture regime that borders on aridic.
Series will be reclassified to the proposed Torrertic subgroup when it is approved.