LOCATION BULLION UTEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Xerertic Natrargids
TYPICAL PEDON: Bullion silt loam--on a 2 percent slope--rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 4 inches; light brown (7.5YR 6/4) silt loam, brown (7.5YR 4/4) moist; weak thick platy structure parting to weak thin platy; slightly hard, friable, slightly sticky and slightly plastic; few fine and very fine roots; few medium, many fine and very fine pores; strong effervescence (11 percent calcium carbonate equivalent); carbonates are disseminated; strongly alkaline (pH 9.0); abrupt smooth boundary. (2 to 5 inches thick)
BAn--4 to 6 inches; light brown (7.5YR 6/4) silt loam, strong brown (7.5YR 4/6) moist; weak thick platy structure parting to weak fine subangular blocky; hard, friable, moderately sticky and slightly plastic; few fine and very fine roots; common fine and very fine pores; strong effervescence (14 percent calcium carbonate equivalent); carbonates are disseminated; very strongly alkaline (pH 9.2); abrupt wavy boundary. (0 to 4 inches thick)
Btn--6 to 14 inches; light reddish brown (5YR 6/4) silty clay loam, reddish brown (5YR 4/4) moist; strong coarse and medium prismatic structure parting to moderate fine and very fine subangular blocky; very hard, firm, moderately sticky and moderately plastic; few medium, common fine and very fine roots; few fine and very fine pores; strong effervescence (4 percent calcium carbonate equivalent); carbonates are disseminated; slightly saline; very strongly alkaline (pH 9.4); clear wavy boundary. (7 to 13 inches thick)
Bky--14 to 24 inches; light reddish brown (5YR 6/4) silty clay loam, yellowish red (5YR 4/6) moist; moderate coarse and medium prismatic structure parting to moderate medium subangular blocky; very hard, firm, moderately sticky and moderately plastic; few medium, common fine and very fine roots; few fine and very fine pores; violent effervescence (27 percent calcium carbonate equivalent), carbonates are disseminated; few fine soft gypsum crystals (trace gypsum); strongly saline; very strongly alkaline (pH 9.2); gradual wavy boundary. (6 to 13 inches thick)
Cky1--24 to 38 inches; light reddish brown (5YR 6/4) clay loam, yellowish red (5YR 5/6) moist; moderate medium subangular blocky structure parting to moderate fine subangular blocky; very hard, firm, moderately sticky and moderately plastic; few fine and very fine roots; few fine and very fine pores; violent effervescence (26 percent calcium carbonate equivalent); carbonates are disseminated; many medium and fine soft gypsum crystals (4.4 percent gypsum); strongly saline; very strongly alkaline (pH 9.2); clear wavy boundary. (6 to 15 inches thick)
Cky2--38 to 52 inches; light reddish brown (5YR 6/4) silty clay loam, yellowish red (5YR 5/6) moist; moderate medium subangular blocky structure parting to moderate fine subangular blocky; very hard, firm, moderately sticky and moderately plastic; few fine and very fine roots; few fine and very fine pores; violent effervescence (38 percent calcium carbonate equivalent), carbonates are disseminated; many medium and fine soft gypsum crystals (0.9 percent gypsum); strongly saline; very strongly alkaline (pH 9.1); gradual wavy boundary. (9 to 15 inches thick)
Cky3--52 to 60 inches; light reddish brown (5YR 6/4) silty clay loam, yellowish red (5YR 5/6) moist; moderate medium subangular blocky structure parting to moderate fine subangular blocky; very hard, firm, moderately sticky and moderately plastic; few fine and very fine roots; few fine and very fine pores; many medium and fine soft gypsum crystals (0.2 percent gypsum); moderately saline; violent effervescence (37 percent calcium carbonate equivalent); carbonates are disseminated; very strongly alkaline (pH 9.l).
TYPE LOCATION: Iron County, Utah; about 4 miles northwest of Paragonah on Slough Bench in Parowan Valley; 900 feet north and 1,560 feet east of the southwest corner of section 13, T. 33 S., R. 9 W.; USGS Paragonah 7.5 minute topographic quadrangle; approximately 37 degrees 55 minutes 44 seconds north latitude and 112 degrees 49 minutes 27 seconds west longitude, NAD27.
RANGE IN CHARACTERISTICS:
Soil moisture - These soils are dry for 50 to 60 percent of the time that the soil temperature at a depth of 20 inches is above 41 degrees F. They are usually dry in some part of the moisture control section for 60 to 75 days out of the 120 days following the summer solstice. The moisture regime is aridic bordering on xeric.
Mean annual soil temperature - 47 to 52 degrees F.
Mean summer soil temperature - 66 to 72 degrees F.
Ochric epipedon thickness - 3 to 6 inches.
Particle-size control section - Clay content: 35 to 50 percent.
A horizon - Hue: 7.5YR or 5YR.
Reaction: Moderately alkaline or strongly alkaline.
Salinity (EC): 0 to 4 mmhos/cm.
Sodicity (SAR): 5 to 20.
Calcium carbonate equivalent: 5 to 15 percent.
Btn horizon - Hue: 5YR or 7.5YR.
Value: 5 or 6 dry.
Chroma: 3 through 6, dry or moist.
Texture: Silty clay loam or silty clay.
Reaction: Strongly alkaline or very strongly alkaline (up to pH 11.0)
Salinity (EC): 4 to 8 mmhos/cm.
Sodicity (SAR): 25 to 40.
Calcium carbonate equivalent: 5 to 20 percent.
Bky and Cky horizons - Hue: 5YR or 7.5YR.
Value: 6 or 7 dry, 3 through 5 moist.
Chroma: 2 through 6, dry or moist.
Texture: Dominantly clay loam or silty clay loam, but may be loam or very fine sandy loam.
Reaction: Strongly alkaline or very strongly alkaline (up to pH 11.0).
Salinity (EC): 8 to 32 mmhos/cm.
Sodicity (SAR): 25 to 55.
Calcium carbonate equivalent: 15 to 40 percent.
Gypsum content: 2 to 20 percent.
Btb horizon (when present) - Hue: 5YR or 7.5YR.
Value: 3 through 5 moist.
Chroma: 3 through 6, dry or moist.
Texture: Sandy clay loam, clay loam, or silty clay loam.
Reaction: Strongly alkaline or very strongly alkaline (up to pH 11.0).
Salinity (EC): 16 to 25 mmhos/cm.
Sodicity (SAR): 25 to 30.
Calcium carbonate equivalent: 10 to 20 percent.
COMPETING SERIES: These are the Final and Updike series.
Final soils have endosaturation within 1 to 2.5 feet of the soil surface in late spring. Updike soils do not have horizons with identifiable secondary carbonates and gypsum.
GEOGRAPHIC SETTING: Bullion soils are on alluvial flats and on toeslope positions of alluvial fans. These soils formed in alluvium derived dominantly from sedimentary, basic igneous, and intermediate igneous rocks. Slopes are 0 to 5 percent. Elevations range from 5,000 to 6,000 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 Harding, Magna, and Woodrow soils. Harding soils have hue of 10YR and have a calcic horizon. They are intermixed with the Bullion soils. Magna soils have an aquic moisture regime, mollic epipedons and calcic horizons, and occur in depressions below Bullion soils. Woodrow soils have an irregular decrease in organic carbon with depth, do not have a natric horizon and are fine-silty. They occur in broad drainageways on alluvial plains.
DRAINAGE AND PERMEABILITY: Well drained; very high surface runoff; very slow permeability.
USE AND VEGETATION: Bullion soils are used principally for rangeland. A few areas west of Cedar City are being used for urban development. The native vegetation is black greasewood, shadscale, bottlebrush squirreltail, perfoliated peppergrass, kochia, and halogeton.
DISTRIBUTION AND EXTENT: Southwestern Utah. These soils are moderately extensive. MLRA 28A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona.
SERIES ESTABLISHED: Iron County (Beryl-Enterprise Area), Utah, 1942.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 4 inches (A horizon).
Natric horizon - The zone from 6 to 14 inches (Btn horizon).
Identifiable secondary carbonates - The zone from 14 to 60 inches (Bky, Cky1, Cky2, and Cky3 horizons).
Vertic feature - The zone from the soil surface to 40 inches with linear extensibility of 6 cm or more.
Particle-size control section - The zone from 6 to 14 inches (Btn horizon).
This revision of November 2003 updates the taxonomic class from Fine, smectitic, mesic Vertic Natrargids based on the ninth edition of the Keys to Soil Taxonomy, 2003. The classification was previously changed in 1994 from Fine, montmorillonitic, mesic Xerollic Natrargids to Vertic Natrargids.
ADDITIONAL DATA: Two pedons sampled as Bullion in Davis County, Utah have characterization data from the Riverside, CA Soil Survey Laboratory as soil survey sample numbers S73UT-011-001 (pedon # 73C0080) and S73UT-011-002 (pedon # 73C0081).