LOCATION BIGPACK UTEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, calcareous, frigid Aridic Ustorthents
TYPICAL PEDON: Bigpack silt loam, on a southwest facing, convex, 4 percent slope in winterfat/sagebrush/western wheatgrass rangeland at an elevation of 6,560 feet. (Colors are for dry soil unless otherwise noted.)
A--0 to 4 inches; brown (10YR 5/3) silt loam, very dark gray brown (10YR 3/2) moist; weak medium subangular blocky structure parting to weak granular; soft, friable, slightly sticky and slightly plastic; many very fine and fine, few medium roots; common very fine tubular pores; strongly effervescent (12 percent calcium carbonate equivalent), carbonates are disseminated; moderately alkaline (pH 8.4); abrupt smooth boundary. (2 to 4 inches thick)
C1--4 to 32 inches; pale brown (10YR 5/3) loam, brown (10YR 4/3) moist; moderate medium and coarse subangular blocky structure; soft, friable, slightly sticky and slightly plastic; common very fine and fine, few medium roots; common very fine, few medium tubular pores; strongly effervescent (13 percent calcium carbonate equivalent), carbonates are disseminated; strongly alkaline (pH 8.6); discontinuous smooth boundary.
C2--32 to 50 inches; pale brown (10YR 5/3) loam, brown (10YR 4/3) moist; massive; soft, friable, slightly sticky and slightly plastic; common very fine and fine roots; common very fine, few medium pores; strongly effervescent (14 percent calcium carbonate equivalent), carbonates are disseminated; moderately alkaline (pH 8.4); gradual smooth boundary.
C3--50 to 60 inches; light yellowish brown (10YR 6/3) clay loam, brown (10YR 4/3) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few very fine and fine roots; few very fine and fine tubular pores; strongly effervescent (13 percent calcium carbonate equivalent), carbonates are disseminated; moderately alkaline (pH 8.4).
TYPE LOCATION: Uintah County, Utah; about 21 miles south of Bonanza; located about 1,200 feet north and 1,100 feet east of the southwest corner of sec. 35, T. 12 S., R. 24 E., SLBM; Burnt Timber Canyon USGS quad; lat. 39 degrees 43 minutes 38 seconds N. and long. 109 degrees 12 minutes 7 seconds W., NAD 27
RANGE IN CHARACTERISTICS:
Soil moisture: The soil moisture control section is affected by precipitation that falls evenly through the year with a slight increase in late summer and early fall. Ustic moisture regime bordering on aridic.
Mean annual soil temperature: 44 to 47 degrees F.
Particle-size control section: 18 to 35 percent clay
A horizon:
Value: 5 to 7 dry, 3 or 4 moist
Chroma: 2 to 4 dry or moist
Texture: loam or silt loam
Calcium carbonate equivalent: 5 to 15 percent
C horizon:
Value: 5 to 7 dry, 4 to 6 moist
Chroma: 2 or 4 dry or moist
Texture: loam or clay loam
Calcium carbonate equivalent: 5 to 15 percent
Gypsum: 0 to 2 percent
Reaction: moderately alkaline or strongly alkaline
COMPETING SERIES: Current competitors are the Benz, Delridge, Hillon, and Patent series. A competitor prior to the Eighth Edition, 1998 Keys to Soil Taxonomy is the Mussel series.
Benz, Hillon, Mussel, and Patent: have soil moisture control sections affected by peak periods of precipitation in the spring and early summer
Benz: have C horizons that are strongly alkaline, have ESP greater than 15, and EC greater than 8 mmhos/cm
Hillon and Mussel: have accumulations of secondary calcium carbonate.
Patent: have thin strata of contrasting textures
GEOGRAPHIC SETTING:
Parent material: alluvium derived from sedimentary and metamorphic rocks
Landform: alluvial flats
Slopes: 1 to 8 percent
Elevation: 6,500 to 7,300 feet
Mean annual air temperature: 42 to 45 degrees F.
Mean annual precipitation: 12 to 16 inches
Frost-free period: 90 to 110 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Gompers, Pathead, Towave, and Whetrock series.
Gompers, Pathead, Towave, and Whetrock soils occur on higher hillslope positions and have more than 35 percent rock fragments in the particle-size control section.
Gompers soils are shallow to bedrock.
Whetrock soils have mollic epipedons.
DRAINAGE AND PERMEABILITY: Well drained, medium runoff, moderately slow permeability.
USE AND VEGETATION: The major uses are range and wildlife habitat, and as irrigated cropland in some localities. Potential native vegetation consists of western wheatgrass, basin big sagebrush, bluebunch wheatgrass, winterfat, and fourwing saltbush. This soil has been correlated to Upland Loam (Basin Big Sagebrush) - 034XY306UT and Upland Silt Loam (Four-wing Saltbush-Winterfat) - 034XY329UT range sites in Utah.
DISTRIBUTION AND EXTENT: Northeast Utah. LRR D, MLRA 34. This series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Uintah County, Uintah Area Soil Survey, Utah. 1998. The name is taken from a nearby geographic name.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Particle-size control section: The zone from 10 to 40 inches. (C1 and C2 horizons)
Ochric epipedon: The zone from 0 to 4 inches. (A horizon)
Taxonomic version: Eighth Edition, 1998.
The cation exchange activity class was inferred from laboratory data from similar soils in the Uintah Area Soil Survey.