LOCATION ELTSAC MT+WYEstablished Series
TAXONOMIC CLASS: Very-fine, smectitic, frigid Leptic Udic Haplusterts
TYPICAL PEDON: Eltsac clay - cultivated. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 6 inches; grayish brown (2.5Y 5/2) clay, dark grayish brown (2.5Y 4/2) moist; strong fine granular structure; very hard, friable, moderately sticky and very plastic; common fine and very fine roots; common very fine pores; slightly effervescent; slightly alkaline (pH 7.6); abrupt wavy boundary.
Bw--6 to 14 inches; grayish brown (2.5Y 5/2) clay, dark grayish brown (2.5Y 4/2) moist; moderate fine and medium subangular blocky structure; extremely hard, firm, moderately sticky and very plastic; common intersecting slickensides; common fine and very fine roots; common very fine pores; slightly effervescent; moderately alkaline (pH 8.4); clear wavy boundary. (6 to 12 inches thick)
Bky--14 to 26 inches; grayish brown (2.5Y 5/2) clay, dark grayish brown (2.5Y 4/2) moist; moderate fine and medium subangular blocky structure; extremely hard, firm, moderately sticky and very plastic; common intersecting slickensides; common very fine and fine roots; common very fine pores; common nests and seams of gypsum and few masses of segregated lime; slightly effervescent; moderately alkaline (pH 8.4); gradual wavy boundary. (10 to 20 inches thick)
Cr--26 to 60 inches; light brownish gray (2.5Y 6/2) semiconsolidated shale; moderately alkaline (pH 8.4).
TYPE LOCATION: Cascade County, Montana; 1,900 feet west and 600 feet south of the northeast corner section 17, T.20N., R.7E.
RANGE IN CHARACTERISTICS:
Soil temperature: 42 to 47 degrees F.
Depth to paralithic contact: 20 to 40 inches.
Cracks range from 1 to 3 inches in width and extend to depths greater than 20 inches during the dry, late summer months
A horizon - Hue: 5Y or 2.5Y
Value: 4 to 6 dry; 3 to 5 moist
Chroma: 1 or 2
Clay content: 50 to 60 percent
EC: less than 2mmhox/cm
Reaction: pH 7.4 to 8.4
Bw and Bky horizons - Hue: 5Y or 2.5Y
Value: 4 or 5 dry
Chroma: 2 or 3
Clay content: 60 to 80 percent
EC: less than 4 mmhos/cm
CaCO3: 5 to 15 percent in the Bky horizon
Reaction: 6.6 to 8.4
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Landform- sedimentary uplands.
Elevation - 3,000 to 5,000 feet.
Slope - 0 to 70 percent.
Parent material - semiconsolidated shale.
Climate - is cool, moist-semiarid, with long, cold, dry winters and warm moist springs and summers.
Mean annual precipitation - 15 to 19 inches, more than 70 percent of which falls in spring and early summer.
Mean annual temperature - 40 to 45 degrees F., mean January temperature is 18 to 25 degrees F. and mean July temperature is 65 to 70 degrees F.
Frost-free period - 110 to 125 days.
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Well-drained; very slow permeability.
USE AND VEGETATION: Eltsac soils are used mainly as rangeland and for dryland crops. Potential native vegetation is mainly western wheatgrass, bluebunch wheatgrass and green needlegrass.
DISTRIBUTION AND EXTENT: Eltsac series are extensive throughout Montana. MLRA 46, 53A, and 58A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Big Horn County (Big Horn Area), Montana, 1970.
REMARKS: Diagnostic horizons and features recognized in this pedon are: an ochric epipedon from the soil surface to 6 inches (Ap horizon); a cambic horizon from 6 to 14 inches (Bw horizon).