LOCATION MIDDLE UTEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, active, mesic Calcic Haploxerolls
TYPICAL PEDON: Middle cobbly silt loam--rangeland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 3 inches; grayish brown (10YR 5/2) cobbly silt loam, very dark grayish brown (10YR 3/2) moist; weak fine and medium granular structure; soft, friable, slightly sticky and slightly plastic, many fine roots; common very fine pores; slightly alkaline (pH 7.8); clear smooth boundary. (2 to 10 inches thick)
A2--3 to 7 inches; brown (10YR 5/3) cobbly silt loam, dark brown (10YR 3/3) moist; weak fine and medium granular structure; soft, friable, slightly plastic; many fine roots; common very fine pores; slightly alkaline (pH 7.8); clear smooth boundary. (6 to 13 inches thick)
Bw1--7 to 12 inches; brown (10YR 5/3) cobbly silt loam, dark brown (10YR 3/3) moist; weak fine and medium subangular blocky structure; soft, friable, slightly sticky and slightly plastic; common fine roots; many fine pores; few faint clay films lining pores and on faces of peds; moderately alkaline (pH 8.0); gradual wavy boundary. (0 to 6 inches thick)
Bw2--12 to 19 inches; brown (10YR 5/3) very cobbly silt loam, brown (10YR 4/3) moist; weak fine and medium subangular blocky structure; soft, firm, slightly sticky and slightly plastic; few fine roots; many fine pores; few faint clay films on faces of peds and lining pores; slightly calcareous; moderately alkaline (pH 8.0); gradual wavy boundary. (0 to 7 inches thick)
Bk--19 to 28 inches; very pale brown (10YR 7/3) very cobbly loam, yellowish brown (10YR 5/4) moist; massive; soft, friable, slightly sticky and slightly plastic; few fine roots; many very fine pores; strongly calcareous; moderately alkaline (pH 8.2); clear wavy boundary. (4 to 9 inches thick)
R--28 to 32 inches; fractured limestone.
TYPE LOCATION: Box Elder County, Utah, about 4 miles southwest of Portage in Rough Canyon, about 2,400 feet east and 1,200 feet north of the SW corner of section 16, T.14N., R.4W.
RANGE IN CHARACTERISTICS: Thickness of the mollic epipedon is generally 9 to 15 inches and ranges from 8 to 20 inches. The layer of carbonate accumulation is at some depth between 16 and 28 inches. The series control section averages very gravelly loam and contains more than 35 percent rock fragments. Rock fragments range from 20 to 50 percent by volume of the A horizon and from 35 to 80 percent of the B and C horizons. The mean annual soil temperature is estimated to be 49 or 50 degrees F. and the mean summer temperature to range from 65 to 73 degrees F.
The A horizons have value of 2 or 3 moist, 4 or 5 dry, and chroma of 2 or 3. It has weak to moderate, very fine to medium granular structure. This horizon is neutral to moderately alkaline and is noncalcareous.
The Bw horizons have hue of 10YR or 7.5YR, value of 3 through 5 moist and 4 through 7 dry, and chroma of 2 through 4. It is very gravelly loam, cobbly loam or very cobbly heavy silt loam. The B horizon has weak to moderate fine and medium subangular blocky structure. It is slightly to moderately alkaline, and noncalcareous to moderately calcareous.
The Bk horizon has hue of 10YR or 7.5YR, value of 4 through 6 moist, and 5 through 7 dry, and chroma of 2 through 4. It is very cobbly light loam or heavy loam. The matrix of the Bk horizon is moderately or strongly calcareous, and has some lime enrichment in the upper part. It ranges from 4 to 40 percent carbonates.
COMPETING SERIES: There are currently no other series in this family.
GEOGRAPHIC SETTING: Middle soils are on mountains. They typically occur on shoulder and backslope positions. These soils formed in residuum and colluvium derived from sandstone, limestone, and some quartzite. Slopes are 10 to 70 percent. Elevations range from 5,000 to 7,000 feet. The climate is dry subhumid. The mean annual temperature is 46 to 47 degrees F., the mean summer temperature is 68 to 69 degrees F., and the mean annual precipitation is 15 to 19 inches. The frost-free period is 80 to 120 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Broad, Picayune, and Richmond soils. Broad soils have argillic horizons that contain less than 35 percent rock fragments and have frigid temperatures. Picayune soils have frigid temperatures and are more than 40 inches deep to bedrock. Richmond soils lack mollic epipedons and have a lithic contact within 20 inches of the surface.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; moderate permeability.
USE AND VEGETATION: This soil is used for rangeland. The native vegetation is bluebunch wheatgrass, cheatgrass, big sagebrush, bitterbrush and annual weeds.
DISTRIBUTION AND EXTENT: Northern Utah. These soils are moderately extensive. MLRAs 28A and 47.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona.
SERIES ESTABLISHED: Northern Utah SCD, Utah, 1941.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 12 inches (A1, A2, and Bw1 horizons).
Cambic horizon - The zone from 12 to 19 inches (Bw2 horizon).
Identifiable secondary carbonates - The zone from 19 to 28 inches (Bk horizon).
Lithic contact - The boundary at 28 inches to underlying bedrock (R layer).
Particle-size control section - The zone from 10 to 28 inches (Bw2 and Bk horizons and part of the Bw1 horizon).
The active cation exchange activity class was added to the taxonomic classification in December 2002 based on soil property data. The remainder of this document has not been completely updated.