LOCATION POKER WYEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive Pachic Argicryolls
TYPICAL PEDON: Poker fine sandy loam-grassland. (Colors are for dry soil unless otherwise stated.)
A--0 to 10 inches; brown (7.5YR 5/3) fine sandy loam, dark brown (7.5YR 3/3) moist; strong fine crumb structure; soft, very friable; slightly acid (pH 6.4); gradual wavy boundary. (6 to 12 inches thick)
AB--10 to 16 inches; reddish brown (5YR 5/3) fine sandy loam, dark reddish brown (5YR 3/3) moist; weak coarse prismatic structure parting to moderate coarse and medium subangular blocky; slightly hard, very friable; few small krotovinas; slightly acid (pH 6.4); gradual wavy boundary. (0 to 6 inches thick)
Bt--16 to 26 inches; reddish brown (5YR 5/3) fine sandy loam, dark reddish brown (5YR 3/3) moist; moderate coarse prismatic structure parting to moderate medium subangular blocky; slightly hard, very friable; common faint clay films on faces of peds; slightly acid (pH 6.4); clear smooth boundary. (6 to 16 inches thick)
BC--26 to 30 inches; brown (7.5YR 5/3) fine sandy loam, brown (7.5YR 4/3) moist; weak medium subangular blocky structure; slightly hard, very friable; few thin clay films on some sand grains; slightly acid (pH 6.4); abrupt smooth boundary. (3 to 6 inches thick)
R--30 inches; sandstone.
TYPE LOCATION: Johnson County, Wyoming; NE1/4, NE1/4, Sec. 5, T. 24 N., R. 85 W.
RANGE IN CHARACTERISTICS: The mollic epipedon and the solum range from 16 to 40 inches thick, and depth to sandstone bedrock ranges from 20 to 40 inches. Organic carbon ranges from .8 to 3 percent in the mollic epipedon and decreases uniformly as depth increases. The soil is 80 to 100 percent base saturated. Coarse fragments range from 0 to 15 percent but are typically less than 10 percent. The mean annual soil temperature ranges from 32 to 46 degrees F., and the mean summer soil temperature ranges from 40 to 58 degrees F.
The A horizon has hue of 10YR through 5YR, value of 4 or 5 dry, 2 or 3 moist, and chroma of 2 or 3. It usually has crumb or granular structure but has subangular blocky or prismatic structure in its lower part in some pedons. This horizon is soft or slightly hard and slightly acid to mildly alkaline.
The Bt horizon has hue of 5YR or 2.5YR, value of 5 or 6 dry, 3 or 4 moist, and chroma of 2 through 4. Reaction ranges from slightly acid to mildly alkaline. This horizon usually has prismatic structure but has subangular blocky structure in some pedons. It is typically sandy loam but clay ranges from 8 to 18 percent, silt from 10 to 35 percent, and sand from 50 to 75 percent with more than 35 percent fine or coarser sand.
COMPETING SERIES: These are the Dreamscape and Sublette series. These soils lack bedrock above a depth of 40 inches.
GEOGRAPHIC SETTING: These soils are on upland hills and ridges where sandstone bedrock lies near the surface. Slopes range from 2 to 25 percent. Elevation is 8,000 to 9,500 feet. These soils formed in moderately coarse textured parent materials weathered residually from noncalcareous reddish brown sandstone. At the type location the average annual precipitation is 20 inches, approximately 14 inches of which fall during April through September. The average annual temperature is 36 degrees F. and the average summer temperature is 55 degrees F. The frost-free season is 60 to 65 days but frost may occur in any summer month.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Sawcreek and Passcreek soils. Sawcreek and Passcreek soils have mollic epipedons less than 16 inches thick. Also, Sawcreek soils lack argillic horizons.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; rapid permeability.
USE AND VEGETATION: These soils are used principally as native pastureland and for recreational purposes. Principal native vegetation is Idaho fescue, green needlegrass, and yarrow.
DISTRIBUTION AND EXTENT: Bighorn Mountain areas of north-central Wyoming. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Johnson County (Southern Johnson County Area), Wyoming; 1971.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon the zone from the soil surface to a depth of 26 inches (A, AB, and Bt horizons);
Argillic horizon - the zone from 16 to 30 inches (Bt and BC horizons).
Lithic contact- the upper boundary of the R horizon 30 inches below the soil surface.