LOCATION SHIRLEYBASIN WYEstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, frigid Ustic Paleargids
Typical Pedon: Shirleybasin loam on a 2 percent convex east-facing slope in native rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 3 inches; pale brown (10YR 6/3) loam, brown (10YR 4/3) moist; moderate very fine granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine roots; neutral (pH 6.8); abrupt wavy boundary. (1 to 5 inches thick)
Bt1--3 to 11 inches; yellowish brown (10YR 5/4) clay, dark yellowish brown (10YR 4/4) moist; moderate medium prismatic structure parting to moderate medium subangular blocky; hard, firm, sticky, and plastic; common very fine and few fine roots; few very fine pores; continuous thin clay films on faces of peds and as linings on pores; neutral (pH 7.2); clear wavy boundary. (8 to 25 inches thick)
Bt2--11 to 19 inches; olive yellow (2.5Y 6/6) clay, light olive brown (2.5Y 5/6) moist; weak coarse prismatic structure; very hard, very firm, sticky, and plastic; few very fine and fine roots; few very fine pores; many thin clay films on faces of peds; mildly alkaline (pH 7.4); gradual wavy boundary. (3 to 17 inches thick)
BC--19 to 34 inches; light yellowish brown (2.5Y 6/4) sandy loam, light olive brown (2.5Y 5/6) moist; massive; slightly hard, friable; few very fine roots; common fine distinct strong brown residual mottles; moderately alkaline (pH 8.2); abrupt wavy boundary. (8 to 27 inches thick)
BCk--34 to 60 inches; pale yellow (5Y 7/3) sandy clay loam, pale olive (5Y 6/3) moist; weak coarse prismatic structure; slightly hard, friable, slightly sticky and slightly plastic; common fine and medium distinct strong brown and reddish brown residual mottles; brown continuous thin coatings on faces of prisms; violently effervescent; carbonates are disseminated; strongly alkaline (pH 8.6).
TYPE LOCATION: Carbon County, Wyoming; 2.0 miles west of Measel Springs Reservoir; 2,300 feet south of the NE corner, Section 31, T28N, R79W.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 40 to 45 degrees F. Thickness of the solum is 16 to 35 inches. Depth to bedrock is 60 inches or more. A layer of secondary carbonates occurs at depth of 30 to 60 inches. The control section has 0 to 15 percent rock fragments. The control section averages more than 35 percent clay, while some individual subhorizons may have less than 35 percent clay.
The A horizon has hue of 7.5YR or 10YR, value of 4 through 6 dry, 3 through 5 moist and chroma of 2 through 4. It is loam, sandy clay loam and clay loam. Reaction is neutral and mildly alkaline.
The Bt horizon has hue of 7.5YR through 10YR, value of 4 through 6 dry, 3 through 5 moist and chroma of 3 through 6. It is clay, clay loam, sandy clay, or sandy clay loam. The horizon is dominantly 35 to 40 percent clay but ranges from 25 to 45 percent clay in some subhorizons. Reaction is neutral through moderately alkaline but dominantly neutral or mildly alkaline.
Where a Bt3 is present, hue is 10YR and 2.5Y, value is 5 or 6 dry, 4 or 5 moist, and chroma is 3 through 6. It is clay, sandy clay, sandy clay loam, and clay loam. Reaction is neutral through moderately alkaline but dominantly mildly or moderately alkaline.
The BC horizon has hue of 10YR through 5Y with 5YR or 7.5YR in some lower layers. Value is 5 through 8 dry, 4 through 7 moist. Chroma is 2 through 6. Texture is dominantly sandy loam to sandy clay but also includes loamy sand. It is dominantly 10 to 25 percent clay. This horizon commonly has 0 to 15 percent fine pebbles but may range from 15 to 50 percent fine pebbles in some thin layers. Structure may range from strong coarse prismatic to massive depending upon the degree of weathering in this highly variable thinly interbedded material. Reaction is dominantly neutral to moderately alkaline with some strongly and very strongly alkaline lower layers.
COMPETING SERIES: These are the Lahtida and Whiteriver series. Lahtida soils have a paralithic contact at a depth of 20 to 40 inches. Whiteriver soils have a 2B horizon composed of tuffaceous material.
GEOGRAPHIC SETTING: Shirleybasin soils are on broad pediment surfaces that have a flat or convex surface. The soil formed in a thin veneer of alluvium over residuum from the White River and Wind River formations. The slope gradient is commonly from 0 to 15 percent, but ranges to 30 percent. Elevation is 7,000 to 7,400 feet. Mean annual temperature ranges from 40 to 45 degrees F. and the mean annual precipitation ranges from 10 to 14 inches. The frost-free season is about 85 to 110 days depending upon aspect and air drainage.
GEOGRAPHICALLY ASSOCIATED SOILS: These are Bateson, Moyerson, Tisworth, and Whiteriver soils. Bateson soils average less than 35 percent clay in the control section. Moyerson soils ae shallow over sandstone. Tisworth soils have a layer of sodium accumulation. Whiteriver soils have an accumulation of calcium carbonate above 30 inches.
DRAINAGE AND PERMEABILITY: Well drained. Runoff is slow or medium. Permeability is slow.
USE AND VEGETATION: Rangeland and wildlife habitat are the primary use on these soils. Big sagebrush, bluebunch wheatgrass, western wheatgrass, mutton bluegrass, and needleandthread are the dominant species in the potential plant community.
DISTRIBUTION AND EXTENT: Shirleybasin soils are moderately extensive in south-central Wyoming.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Albany County (Albany County Area), Wyoming, 1991. The name is taken from the topographic feature of Shirleybasin where this series was proposed.
REMARKS: Diagnostic horizons and features recognized in this pedon are: Ochric epipedon - The zone from the surface of the soil to a depth of approximately 3 inches (A) horizon); Argillic horizon - The zone from approximately 3 inches to 19 inches (Bt1, Bt2 horizons); Borollic feature - meets organic carbon and soil temperature regime requirement for Borollic.