LOCATION FIRMAGE UTEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Xeric Haplocalcids
TYPICAL PEDON: Firmage very cobbly loam, rangeland. (Colors are for air-dry soil unless otherwise noted.)
A--0 to 8 inches; light brownish gray (10YR 6/2) very cobbly loam, dark grayish brown (10YR 4/2) moist; weak fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; few fine tubular pores; common fine, medium and few coarse roots; strongly calcareous; moderately alkaline (pH 8.4); clear wavy boundary. (7 to 11 inches thick)
Bk1--8 to 33 inches; very pale brown (10YR 8/2) cobbly loam, very pale brown (10YR 7/3) moist; massive; extremely hard, friable, slightly sticky; few fine tubular pores; few fine, medium and coarse roots; strongly calcareous; carbonates have discontinuous weak cementation; strongly alkaline (pH 8.6); gradual wavy boundary. (12 to 25 inches thick)
Bk2--33 to 60 inches; white (10YR 8/1) cobbly sandy loam, very pale brown (10YR 7/3) moist; massive; very hard, friable, slightly sticky; few fine tubular pores; few fine and medium roots; very strongly calcareous; carbonates have discontinuous weak cementation; strongly alkaline (pH 8.6).
TYPE LOCATION: Millard County, Utah; 5 miles east and 5 miles north of Antelope Point; 3/4 miles west of SE corner of sec. 22, T. 24 S., R. 8 W.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 47 to 54 degrees F., and the mean summer soil temperature at a depth of 20 inches is 63 to 65 degrees F. These soils are dry 45 to 75 percent of the time the soil temperature is above 41 degrees F.
Depth to the calcic horizon ranges from 7 to 16 inches, and this horizon is 27 to 60 inches thick. Rock fragments are mostly pebbles and cobbles and range from 15 to 35 percent by volume in the particle size control section. The particle-size control section has 18 to 27 percent clay and more than 15 percent sand coarser than very fine sand.
The A horizon has value of 5 or 6 dry, 3 or 4 moist, and chroma of 2 or 4. Textures are gravelly fine sandy loam, very cobbly loam, fine sandy loam, and loam.
Some pedons have Bw horizons with value of 6 or 7 dry, 4 or 5 moist, and chroma of 3 or 4. Texture is loam or clay loam. Reaction is moderately or strongly alkaline.
The Bk horizon has value of 7 or 8 dry, 5 through 7 moist, and chroma of 1 through 4. It is strongly calcareous or very strongly calcareous. Textures are a cobbly loam, cobbly sandy loam, gravelly loam, fine sandy loam, loam, clay loam, cobbly clay loam, stony loam and very cobbly sandy clay loam. Reaction is moderately to strongly alkaline.
Some pedons have C horizons with 15 to 55 percent rock fragments. Value of 7 or 8 dry, 6 or 7 moist, and chroma of 2 or 3. Reaction is moderate to strongly alkaline.
COMPETING SERIES: These are the Komo (T UT) and Taylorsflat (UT) series. Komo soils have hues dominantly of 2.5YR. Taylorsflat soils lack rock fragments in the particle-size control section. Also, the Taylorsflat soils have calcic horizons below a depth of 20 inches or more.
GEOGRAPHIC SETTING: Firmage soils are on alluvial fans and undulating to steep rolling hills at elevations of 4,900 to 6,600 feet. Slopes range from 2 to 30 percent. The soils formed in deep calcareous alluvium from limestone and conglomerate. The climate is dry subhumid. Mean annual air temperature is 45 to 52 degrees F., mean summer temperature is 64 to 66 degrees F., and the average annual precipitation is 10 to 14 inches. March, April, and May are the wettest months and June is the driest. Freeze-free period is 100 to 150 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Oakden, Mill Hollow, and Ushar soils. Oakden soils have a lithic contact to limestone bedrock within a depth of 20 inches. Mill Hollow soils lack rock fragments in the particle-size control section and have mollic epipedons. Ushar soils have cambic horizons and lack rock fragments in the particle-size control section.
DRAINAGE AND PERMEABILITY: Well-drained; medium to rapid runoff; moderate and moderately slow permeability.
USE AND VEGETATION: These soils are used as winter range for sheep and wildlife. Potential vegetation is bluebunch wheatgrass, Indian ricegrass and big sagebrush.
DISTRIBUTION AND EXTENT: North end of East Beaver Survey Area and south end of Millard County. MLRA D28A. These soils are inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Millard County, Utah, 1972.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from 0 to 8 inches (A horizon).
Calcic horizon - the zone from 8 to 60 inches (Bk1, Bk2 horizons).
Particle-size control section - the zone from 10 to 40 inches.