LOCATION ROMINELL MTEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Aridic Leptic Natrustalfs
TYPICAL PEDON: Rominell loam, rangeland. (Colors are for dry soil unless otherwise noted)
A--0 to 4 inches; grayish brown (2.5Y 5/2) loam, very dark grayish brown (2.5Y 3/2) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and slightly plastic; many fine roots throughout horizon; common fine tubular pores; noncalcareous; slightly alkaline (pH 7.8); clear smooth boundary. (0 to 4 inches thick)
E--4 to 9 inches; light brownish gray (2.5Y 6/2) fine sandy loam, dark grayish brown (2.5Y 4/2) moist; weak medium prismatic structure parting to weak medium subangular blocky; soft, very friable, nonsticky and nonplastic; many fine roots throughout horizon; many fine tubular pores; slightly effervescent; moderately alkaline (pH 8.4); abrupt smooth boundary. (3 to 5 inches thick)
Btn--9 to 15 inches; light brownish gray (2.5Y 6/2) clay loam, brown (2.5Y 4/3) moist; strong medium columnar structure parting to strong medium angular blocky, very hard, firm, sticky and plastic; many fine roots throughout horizon; many fine tubular pores; common faint clay films on faces of peds; many distinct light gray (2.5Y 7/2) skeletans on tops and sides of columns; strongly effervescent; very strongly alkaline (pH 9.6); clear wavy boundary. (5 to 15 inches thick)
Bnyz--15 to 25 inches; light olive brown (2.5Y 5/4) loam, dark brown (10YR 3/3) moist; moderate coarse prismatic structure parting to moderate medium subangular blocky; hard, friable, slightly sticky and slightly plastic; common fine roots throughout horizon; common to many fine tubular pores; few light gray (2.5Y 7/2) skeletans on vertical faces of peds; few fine gypsum crystals; violently effervescent; very strongly alkaline (pH 9.6); gradual wavy boundary. (4 to 13 inches thick)
Byz--25 to 55 inches; brown (10YR 5/3) clay loam, dark brown (10YR 3/3) moist; massive; hard, friable, sticky and slightly plastic; few to common fine roots throughout horizon; common fine tubular pores; few fine gypsum crystals; violently effervescent; very strongly alkaline (pH 9.2); gradual wavy boundary. (4 to 29 inches thick)
C-55 to 61 inches; light olive brown (2.5Y 5/4) loam, dark grayish brown (2.5Y 4/2) moist; massive; slightly hard, very friable, sticky and slightly plastic; few fine roots throughout horizon; common fine tubular pores; few hard rock fragments; violently effervescent; very strongly alkaline (pH 9.2).
TYPE LOCATION: McCone County, Montana; about 1,700 feet east and 1,700 feet south of the NW corner of sec. 19, T. 24 N., R.48 E.
RANGE IN CHARACTERISTICS:
Soil temperature - 40 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 41 degrees F. or higher.
A horizon - Hue: 10YR or 2.5Y
Value: 5 or 6 dry, 3 or 4 moist
Chroma: 2 or 3
Texture: very fine sandy loam, sandy loam, loam, fine sandy loam or clay loam
Clay content: 10 to 25 percent
Reaction: pH 6.6 to 8.4
E horizon - Hue: 10YR or 2.5Y
Value: 6 or 7 dry; 4 or 5 moist
Chroma: 1 or 2
Texture: very fine sandy loam, fine sandy loam, silt or clay loam
Clay content: 10 to 27 percent
Calcium carbonate equivalent: 0 to 5 percent
Reaction: pH 7.4 to 8.4
Btn horizon - Hue: 10YR or 2.5Y
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 2 or 3
Texture: clay loam, sandy clay loam or loam
Clay content: 20 to 35 percent
Primary structure: columnar or prismatic
EC: 2 to 8 mmhos/cm
SAR: 13 to 30
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 8.4 to 9.6
Bnyz horizon - Hue: 10YR, 2.5Y or 5Y
Value: 5 or 6 dry; 3, 4, or 5 moist
Chroma: 2, 3, or 4
Texture: sandy clay loam, clay loam sandy loam or loam
Clay content: 18 to 35 percent
Gypsum: 1 to 3 percent
SAR: 5 to 15
Calcium carbonate equivalent: 5 to 15 percent
EC: 2 to 8 mmhos/cm
Reaction: pH 7.9 to 9.6
Byz horizon - Hue: 10YR or 2.5Y
Value: 5 or 6 dry; 3, 4 or 5 moist
Chroma: 2 or 3
Texture: clay loam, loam, sandy loam or sandy clay loam
Clay content: 18 to 35
Gypsum: 1 to 3 percent
EC: 2 to 8 mmhos/cm
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.9 to 9.6
C horizon - Hue: 2.5Y
Value: 5, 6, or 7 dry; 4 or 5 moist
Chroma: 2, 3, or 4 Texture: fine sandy loam, loam, clay loam, silty clay loam or sandy clay loam
Clay content: 10 to 35 percent
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.9 to 9.6
COMPETING SERIES:
Toston (MT) - has a seasonal high water table at depths of 24 to 42 inches; has redox concentrations as shallow as 16 inches.
GEOGRAPHIC SETTING:
Landform - sedimentary plains; stream terraces; alluvial fans
Elevation - 1,800 to 4,100 feet
Slope- 0 to 15 percent
Parent material - alluvium
Climate - long, cold winters; moist springs; warm summers
Mean annual precipitation - 10 to 14 inches
Mean annual air temperature - 38 to 45 degrees F
Frost free period - 100 to 135 days
DRAINAGE AND PERMEABILITY: Well drained; slow permeability.
USE AND VEGETATION: Rominell soils are used mainly for rangeland; some small areas are used for dry cropland. Potential native vegetation is western and thickspike wheatgrass, green needlegrass, needleandthread, winterfat, and various perennial short grasses.
DISTRIBUTION AND EXTENT: Rominell soils are of moderate extent in central and eastern Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: McCone County, Montana, 1981.
REMARKS: Soil Interpretations Record: MT0425. Diagnostic horizons and features recognized in this pedon are: an ochric epipedon from the soil surface to 9 inches (A, E horizons); a natric horizon from 9 to 15 inches (Btn horizon); accumulations of gypsum and other salts from 15 to 55 inches (Bnyz, Byz horizons); a particle-size control section from 9 to 15 inches (Btn horizon).