LOCATION SHEEP CREEK UT+IDEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Calcic Argixerolls
TYPICAL PEDON: Sheep Creek cobbly loam--rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 7 inches; brown (10YR 5/3) cobbly loam, dark brown (10YR 3/3) moist; weak medium granular structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine, few medium and large roots; few very fine discontinuous pores; neutral (pH 7.0); clear smooth boundary. (6 to 12 inches thick)
Bt--7 to 15 inches; brown (7.5YR 5/3) very cobbly clay loam, dark brown (7.5YR 3/3) moist; moderate medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; many very fine and fine and few medium and large roots; few very fine discontinuous pores; common faint clay films on faces of peds and lining pores; neutral (pH 7.1); clear smooth boundary. (6 to 18 inches thick)
Bk--15 to 28 inches; brown (10YR 5/3) very cobbly loam, brown (7.5YR 4/3) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine discontinuous pores; strongly effervescent; secondary carbonates are noncemented and massive; slightly alkaline (pH 7.4); gradual irregular boundary. (8 to 17 inches thick)
R--28 inches; fractured limestone; with fine-earth soil material like the Bk horizon and carbonate accumulation lining fractures.
TYPE LOCATION: Cache County, Utah; about 6 miles south-southwest of Avon in Threemile Canyon; approximately 1,200 feet north and 400 feet west of the southeast corner of section 5, T. 8 N., R. 1 E.; USGS James Peak 7.5 minute topographic quadrangle; 41 degrees 27 minutes 21 seconds north latitude and 111 degrees 51 minutes 14 seconds west longitude, NAD27.
RANGE IN CHARACTERISTICS:
Soil moisture - The soils are moist for 55 to 65 percent of the time and are dry in all parts of the moisture control section (about 8 to 24 inches) for 60 to 75 consecutive days in the summer and autumn; Xeric moisture regime that borders on aridic.
Mean annual soil temperature - 38 to 45 degrees F.
Mean summer soil temperature - 60 to 65 degrees F.
Mollic epipedon thickness - 7 to 20 inches.
Depth to base of argillic horizon - 13 to 23 inches.
Depth to secondary carbonates - 13 to 23 inches.
Depth to bedrock - 22 to 40 inches to a lithic contact.
Particle-size control section - Clay content: 20 to 35 percent;
Rock fragments: 35 to 70 percent, mainly cobbles and rounded gravel. Lithology of fragments are limestone and calcareous sandstone.
A horizon
Hue: 5YR through 10YR.
Value: 3 through 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Texture: cobbly loam, gravelly sandy loam, gravelly loam, or very cobbly loam.
Rock fragments: 15 to 50 percent.
Structure: Weak to moderate, fine to coarse granular.
Reaction: Neutral or slightly alkaline.
Effervescence: Noneffervescent or slightly effervescent.
Organic matter content: 3 to 5 percent.
Bt horizon
Hue: 5YR through 10YR.
Value: 3 through 6 dry, 3 or 4 moist; moist value of 4 occurs at depths below 10 inches.
Chroma: 2 through 4, dry or moist; chroma of 4 occurs at depths below 10 inches.
Texture: Very cobbly clay loam, very cobbly loam, very cobbly sandy clay loam, very cobbly silt loam, very cobbly silty clay loam, very gravelly clay loam, or extremely cobbly silty clay loam.
Structure: Weak or moderate, medium to fine subangular blocky.
Reaction: Neutral through moderately alkaline.
Effervescence: Noneffervescent to slightly effervescent.
Other features: Few to many faint clay films on faces peds and lining pores.
Bk horizon
Hue: 5YR through 10YR.
Value: 5 through 7 dry, 4 or 5 moist.
Chroma: 2 through 6, dry or moist.
Texture: Very cobbly loam, very cobbly clay loam, very cobbly fine sandy loam, extremely gravelly loam, extremely gravelly sandy loam, or extremely cobbly loam.
Structure: Weak medium to fine subangular blocky or is massive.
Reaction: Slightly through moderately alkaline.
Effervescence: Slightly effervescent or strongly effervescent.
Calcium carbonate equivalent: 5 to 30 percent.
COMPETING SERIES: These are the Amelar, Broad, Custco, Drage, Rawnjay, Remount, Scalfar, Searla, Small (T), and Swampydraw (T) series.
Amelar, Custco, Drage, Rawnjay, Remount, Scalfar, Searla, and Swampydraw soils are very deep. Broad soils have calcic horizons and generally have secondary carbonates that are deeper than 23 inches from the soil surface. Small soils have calcic horizons and have rock fragments that are rhyolite.
GEOGRAPHIC SETTING: Sheep Creek soils are on hills and mountains. They typically occur on south, west, or east-facing backslope positions. These soils formed in colluvium and residuum derived from calcareous sandstone, limestone, or quartzite. Slopes are 5 to 70 percent. Elevations range from 5,500 to 7,450 feet. The climate is moist subhumid with cold, moist winters and warm, dry summers. The mean annual precipitation is 13 to 24 inches, the mean annual temperature is 39 to 44 degrees F., the mean summer temperature is 60 to 65 degrees F., and the frost-free period is 70 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Agassiz, Bickmore, Datwyler, and Smarts soils. Agassiz soils have bedrock at depths of 10 to 20 inches. Bickmore soils have mean summer temperatures of less than 59 degrees F. Smarts soils have mollic epipedons more than 20 inches thick.
DRAINAGE AND PERMEABILITY: Well drained; medium or high surface runoff; moderate permeability (moderately high saturated hydraulic conductivity).
USE AND VEGETATION: Sheep Creek soils are used as rangeland and watershed. The native vegetation is bluebunch wheatgrass and tall native bluegrass, Sandberg's bluegrass, yarrow, mulesear dock, big sagebrush, antelope bitterbrush, and yellowbrush.
DISTRIBUTION AND EXTENT: Northern Utah and southeastern Idaho. These soils are moderately extensive. The series concept and main acreage is in MLRA 47, while other acreage occurs in MLRA 28A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona.
SERIES ESTABLISHED: Cache County, Utah, 1972.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 7 inches (A horizon).
Argillic horizon - The zone from 7 to 15 inches (Bt horizon).
Identifiable secondary carbonates - The zone from 15 to 28 inches (Bk horizon).
Lithic contact - The boundary at 28 inches to underlying hard, unweathered bedrock (R layer).
Particle-size control section - The zone from 7 to 15 inches (Bt horizon).
Future study should be done about criteria to separate this series from the Broad series, to determine whether Sheep Creek soils commonly have calcic horizons, and to confirm the cation exchange activity class.