LOCATION SHOTWELL UTEstablished Series
TAXONOMIC CLASS: Loamy, mixed, superactive, calcareous, mesic Lithic Xeric Torriorthents
TYPICAL PEDON: Shotwell very cobbly loam rangeland (Colors are for dry soils unless otherwise noted.)
A--0 to 3 inches; light brownish gray (10YR 6/2) very cobbly loam, dark grayish brown (10YR 4/2) moist; weak thin platy structure that parts to weak fine granules; slightly hard, friable, slightly sticky, slightly plastic; few fine roots; many fine and few medium tubular pores; moderately calcareous; moderately alkaline (pH 8.3); abrupt smooth boundary. (2 to 4 inches thick)
Bw--3 to 12 inches; pale brown (10YR 6/3) loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic; few fine, medium and coarse roots; few fine tubular pores; strongly calcareous; moderately alkaline (pH 8.3); gradual irregular boundary. (8 to 16 inches thick)
R--12 inches; igneous bedrock.
TYPE LOCATION: Beaver County, Utah; 5 miles north and 2 miles east of Antelope Springs; sec. 14, T.24S., R,7W.; lat. 38 degrees 43 minutes 35.84 seconds N. and long. 112 degrees 49 minutes 59.33 seconds W., NAD 83.
RANGE IN CHARACTERISTICS: Mean annual soil temperature is 50 to 51 degrees F., and the mean summer soil temperature at a depth of 20 inches is 65 to 67 degrees F. These soils are usually dry but are continually moist in some part of the moisture control section for more than 1/4 of the time the soil temperature is above 41 degrees F. The soil moisture regime is Aridic bordering on Xeric.
The soil ranges from 10 to 20 inches deep over glassy volcanic bedrock. Rock fragments are over 50 percent in the surface and less than 20 percent in the rest of the profile.
The A horizon has value of 5 or 6 dry, 3 or 4 moist, and chroma of 2 to 4. It has weak thin platy or weak fine granular structure. It is moderately alkaline or strongly alkaline.
The Bw or C horizons have value of 5 or 6 dry, 4 or 5 moist, and chroma of 3 or 4. It is moderately alkaline or strongly alkaline. The Bw when present doesn't meet the definition of a cambic.
COMPETING SERIES: These are the Beelem (NV) and Tessfive (NV) series. Beelem soils are 4 to 10 inches deep and have a mean annual soil temperature of 53 to 59 degrees F. Tessfive soils contain 20 to 35 percent rock fragments in the particle-size control section.
GEOGRAPHIC SETTING: The Shotwell soils are on mountain slopes and lava plains at elevations of 4,600 to 5,600 feet. Slope gradients are 2 to 30 percent. The soils formed in a mantle of soil material less than 20 inches deep over ignimbrite, obsidian, and other glassy volcanic rocks. The climate is semiarid. Mean annual temperature is 48 to 52 degrees F. The mean summer temperature is 66 to 68 degrees F. The average annual precipitation is 8 to 11 inches. March, April, and May are the wettest months and June the driest. Frost-free period is 105 to 150 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Hiko Peak and Fruitland soils. Hiko Peak soils are gravelly or very gravelly, lack a lithic contact within a depth of 40 inches, and have a calcic horizon. Fruitland soils lack a lithic contact within a depth of 40 inches.
DRAINAGE AND PERMEABILITY: Well drained; rapid runoff; moderate permeability to bedrock.
USE AND VEGETATION: Used mainly for winter range for sheep. Present vegetation is Indian ricegrass, squirreltail, bluebunch wheatgrass, scarlet globemallow, locoweed, big sagebrush, yellowbrush, and cheatgrass.
DISTRIBUTION AND EXTENT: Central and southwestern Utah. MLRA 28A. This series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Beaver County, Utah, 1965.
REMARKS: Diagnostic horizons and features that are recognized in this pedon are:
Ochric epipedon - the zone from the surface of the soil to 3 inches. (A horizon)
Lithic contact - bedrock contact at 12 inches. (R horizon)
The classification is based on the "Keys to Soil Taxonomy, Eighth Edition, 1998".