LOCATION GREYBACK WY+ID UTEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Ustic Haplocryolls
TYPICAL PEDON: Greyback gravelly loam, grassland. (Colors are for dry soil unless otherwise stated.)
A--0 to 7 inches; grayish brown (10YR 5/2) gravelly loam, very dark grayish brown (10YR 3/2) moist; weak fine subangular blocky structure that parts to moderate fine granular; slightly hard, very friable; 15 percent gravel; moderately alkaline (pH 8.0); gradual wavy boundary. (0 to 24 inches thick)
Bw--7 to 18 inches; brown (10YR 5/3) gravelly loam, dark brown (10YR 4/3) moist; moderate fine subangular blocky structure; slightly hard, very friable; 25 percent gravel; slightly effervescent; moderately alkaline (pH 8.0); gradual wavy boundary. (0 to 24 inches thick)
Bk--18 to 60 inches; light yellowish brown (10YR 6/4) very gravelly sandy loam grading to very gravelly loamy sand or sand in the lower part, brown (10YR 5/3) moist; massive; slightly hard, very friable; 50 percent gravel; visible secondary calcium carbonate occurring as concretions and as coatings on pebbles; violently effervescent; moderately alkaline (pH 8.2);
TYPE LOCATION: Lincoln County, Wyoming; approximately 420 feet east and 390 feet south of the center of sec. 11, T.35N., R.119W.
RANGE IN CHARACTERISTICS: The mollic epipedon is 7 to 15 inches thick and depth to calcareous material is 5 to 16 inches. Depth to the skeletal material is 0 to 26 inches. The mollic epipedon has .7 to about 3 percent organic carbon which decreases uniformly with increasing depth. The control section averages loam or sandy loam and usually becomes coarser with increasing depth. It averages less than 18 percent clay. The control section has 35 to 80 percent rock fragments, mainly gravel and cobbles. Mean annual soil temperature is 32 to 46 degrees F.
The A horizon has hue of 2.5Y through 7.5YR, value of 4 or 5 dry, 2 or 3 moist, and chroma of 1 through 3. It is usually granular but has subangular blocky structure in some pedons. This horizon is soft or slightly hard and is neutral to moderately alkaline.
The Bw horizon has hue of 2.5Y through 7.5YR, value of 5 or 6 dry, 4 or 5 moist, and chroma of 2 through 4. It is typically subangular blocky but has weak prismatic structure in some pedons. This horizon is neutral to moderately alkaline.
The Bk or C horizon has hue of 2.5Y through 7.5YR, value of 5 through 7 dry 4 or 5 moist and chroma of 3 or 4. It contains about 3 to 14 percent calcium carbonate equivalent. This horizon is moderately or strongly alkaline.
COMPETING SERIES: These are the Antrobus, Grafen, Handran, Maurice, Middlehill, Midelight, Parachute, Sebud, Supervisor, Surdal, Teemat(T), Thornburgh, Tiban, and Tineman series. Antrobus, Farlow, and Tiban soils have more than 18 percent clay in the particle size control section. Grafen soils have a paralithic contact at 20 to 40 inches. Middlehill, Parachute, Supervisor and Surdal soils have a lithic contact at depths of 20 to 40 inches. Midlight soils have a lithic contact at 40 to 60 inches. Maurice, Sebud, Sup, Thornburgh, and Tineman soils are noncalcareous throughout. Handran and Teemat soils lack cambic horizons.
GEOGRAPHIC SETTING: The Greyback soils are on alluvial fans and high terraces. Slopes usually range from 0 to 12 percent. Elevation ranges from 5800 to 9500 feet. These soils formed in thick, very gravelly, calcareous alluvial parent material within a depth of 40 inches. At the type location the average annual precipitation is 18 inches with nearly equal amounts of precipitation occurring during each month. The mean annual temperature is 39 degrees F., the mean summer temperature is 58 degrees F. The frost-free season is less than 60 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Hobacker and Osmund series. Hobacker soils have mollic epipedons more than 16 inches thick. Osmund soils lack the coarse textured materials above depth of 40 inches.
DRAINAGE AND PERMEABILITY: Somewhat excessively to excessively drained; slow runoff; rapid permeability.
USE AND VEGETATION: These soils are used as native pastureland, as irrigated hay meadow, and in places are used for tilled crops. Native vegetation is bluegrass, sagebrush, and cactus.
DISTRIBUTION AND EXTENT: High mountain valleys of Colorado and Wyoming. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Star Valley Area, Idaho and Wyoming, 1971.
REMARKS: Diagnostic horizons and features recognized in this pedon are: Mollic epipedon--0 to 7 inches (A horizon)
Cambic horizon--7 to 18 inches (Bw horizon)
Horizon of secondary carbonate accumulation--18 to 60 inches
Cryic temperature regime
Ustic moisture regime