LOCATION ARDNAS UTEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Xeric Haplocambids
TYPICAL PEDON: Ardnas loam--rangeland. (Colors are for dry soil unless otherwise noted). The soil surface is covered with 15 percent gravel.
A--0 to 4 inches; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; moderate thick platy structure parting to weak fine granular; soft, very friable, slightly sticky and slightly plastic; common fine and very fine roots; common fine and many very fine vesicular pores; moderately alkaline (pH 8.0); abrupt smooth boundary. (1 to 5 inches thick)
Bw--4 to 20 inches; yellowish brown (10YR 5/4) loam, brown (10YR 4/3) moist; moderate medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; few fine and many very fine roots; few fine and common very fine tubular pores; 5 percent gravel; moderately alkaline (pH 8.0); abrupt wavy boundary. (10 to 16 inches thick)
Bk--20 to 40 inches; yellowish brown (10YR 5/4) loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; few fine and many very fine roots; few very fine tubular pores; 10 percent gravel; slightly effervescent; secondary carbonates are disseminated in the matrix and segregated on bottoms of rock fragments; moderately alkaline (pH 8.4); gradual wavy boundary. (14 to 24 inches thick)
Ck--40 to 60 inches; yellowish brown (10YR 5/4) sandy loam, brown (10YR 4/3) moist; massive; soft, very friable, slightly sticky and slightly plastic; few fine and common very fine roots; few very fine tubular pores; 5 percent gravel; slightly effervescent; secondary carbonates are disseminated in the matrix and segregated on bottoms of rock fragments; moderately alkaline (pH 8.2).
TYPE LOCATION: Iron County, Utah; about 4.6 miles northeast of Modena; 240 feet south and 2,380 feet east of the northwest corner of section 16, T. 34 S., R. 18 W; USGS Heist 7.5 minute topographic quadrangle; 37 degrees 51 minutes 04 seconds north latitude and 113 degrees 52 minutes 08 seconds west longitude, NAD27.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually moist in winter and spring, dry mid-June through early October; aridic moisture regime that borders on xeric.
Mean annual soil temperature - 47 to 51 degrees F.
Depth to base of cambic horizon - 12 to 40 inches.
Solum thickness and depth to secondary carbonates - 12 to 40 inches.
Particle-size control section - Clay content: 18 to 27 percent; Rock fragments: 0 to 15 percent, mainly gravel. Lithology of fragments are igneous (volcanic) rocks such as andesite and rhyolite.
A horizon - Value: 4 through 6 dry, 3 or 4 moist.
Chroma: 3 or 4, dry or moist.
Bw horizon - Value: 5 or 6 dry, 4 or 5 moist.
Chroma: 3 or 4, dry or moist.
Texture: Loam or silt loam.
Calcium carbonate equivalent: 0 to 5 percent.
Bk horizon - Value: 5 or 6 dry, 4 or 5 moist.
Chroma: 3 or 4, dry or moist.
Texture: Loam or silt loam.
Calcium carbonate equivalent: 5 to 10 percent.
Ck horizons - Value: 5 through 7 dry, 4 or 5 moist.
Chroma: 3 or 4, dry or moist.
Texture: Loam, fine sandy loam, or sandy loam.
Clay content: 10 to 20 percent.
Calcium carbonate equivalent: 5 to 10 percent.
COMPETING SERIES: These are the Eastable, Ferdelford, Legler, North Powder, Oxman, and Pocan series.
Eastable soils do not have horizons with identifiable secondary carbonates. Ferdelford, North Powder, and Oxman soils are moderately deep to paralithic contacts. Legler soils have a solum that is 40 to 60 inches thick and have buried argillic horizons. Pocan soils are deep to lithic contacts.
GEOGRAPHIC SETTING: Ardnas soils are on fan remnants. They typically occur on toeslope positions. These soils formed in alluvium derived from andesite, rhyolite, and other basic and intermediate igneous rocks. Slopes are 0 to 2 percent. Elevations range from 5,000 to 5,400 feet. The mean annual precipitation is 8 to 10 inches, the mean annual temperature is 45 to 50 degrees F., and the frost-free period is 120 to 140 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Garbo, Sevy, and Wales soils. Garbo soils have durinodes and calcic horizons. Sevy soils have argillic and calcic horizons. Wales soils are stratified and do not have diagnostic subsurface horizons.
DRAINAGE AND PERMEABILITY: Well drained; low surface runoff; moderate permeability.
USE AND VEGETATION: Ardnas soils are used for livestock grazing and wildlife habitat. The present vegetation is mainly winterfat, bottlebrush squirreltail, Indian ricegrass, fourwing saltbush, low rabbitbrush, and galleta.
DISTRIBUTION AND EXTENT: Western Utah. These soils are not extensive with about 4,200 acres of the series mapped to date. MLRA 28A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona.
SERIES ESTABLISHED: Iron-Washington Area, Utah, 1997.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 4 inches (A horizon).
Cambic horizon - The zone from 4 to 20 inches (Bw horizon).
Identifiable secondary carbonates - The zone from 20 to 60 inches (Bk and Ck horizons).
Particle-size control section - The zone from 10 to 40 inches (Bk horizon and part of the Bw horizon).