LOCATION FIRSTGAP UTEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, active, mesic Leptic Haplogypsids
TYPICAL PEDON: Firstgap loam, on northeast-facing, convex, 12 percent slope in shadscale rangeland at an elevation of 5,075 feet. (Colors are for dry soil unless otherwise noted.)
The surface is covered by 25 percent subrounded and subangular gravel.
A1--0 to 2 inches; very pale brown (10YR 7/4) loam, brown (10YR 4/3) moist; weak thick platy structure parting to weak very fine subangular blocky; slightly hard, very friable, nonsticky and nonplastic; few very fine, fine and medium roots; common very fine, few fine vesicular pores; 10 percent gravel; slightly effervescent (11 percent calcium carbonate equivalent), carbonates are disseminated; moderately alkaline (pH 8.2); abrupt smooth boundary. (2 to 4 inches thick)
A2--2 to 5 inches; very pale brown (10YR 7/4) loam, yellowish brown (10YR 5/4) moist; weak coarse subangular blocky structure parting to moderate very fine subangular blocky; slightly hard, friable, slightly sticky and slightly plastic; common very fine, few fine roots; common very fine, few fine tubular pores; slightly effervescent (19 percent calcium carbonate equivalent), carbonates are disseminated; moderately alkaline (pH 8.3); abrupt wavy boundary. (3 to 5 inches thick)
By1--5 to 14 inches; pale yellow (2.5Y 8/4) gypsiferous loam, light yellowish brown (2.5Y 6/4) moist; weak fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and nonplastic; few very fine and fine roots; many very fine and medium, common fine tubular pores; many fine soft powdery gypsum veins and masses (60 percent calcium sulfate); slightly effervescent (8 percent calcium carbonate equivalent), carbonates are disseminated; moderately alkaline (pH 8.0); clear smooth boundary. (9 to 13 inches thick)
By2--14 to 20 inches; pale yellow (2.5Y 7/4) gypsiferous clay loam, light olive brown (2.5Y 5/4) moist; weak fine and medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; few very fine and fine roots; common very fine, few fine tubular pores; many fine gypsum crystals and veins (35 percent calcium sulfate); slightly effervescent (9 percent calcium carbonate equivalent), carbonates are disseminated; moderately alkaline (pH 8.0); clear smooth boundary. (6 to 21 inches thick)
By3--20 to 25 inches; pale yellow (2.5Y 7/3) gypsiferous clay loam, light yellowish brown (2.5Y 6/4) moist; moderate very fine and fine subangular blocky structure; hard, firm, moderately sticky and moderately plastic; few very fine and fine roots; common very fine, few fine tubular pores; few fine gypsum crystals and many fine soft powdery veins (29 percent calcium sulfate); slightly effervescent (10 percent calcium carbonate equivalent), carbonates are disseminated; moderately alkaline (pH 8.1); clear wavy boundary. (5 to 21 inches thick)
By4--25 to 32 inches; pale yellow (2.5Y 7/5) channery clay loam, light olive brown (2.5Y 5/4) moist; moderate very fine and fine angular blocky structure; very hard, firm, moderately sticky and moderately plastic; few very fine roots; few very fine and fine tubular pores; 20 percent channers; few fine gypsum crystals and common fine gypsum veins; very slightly effervescent (10 percent calcium carbonate equivalent), carbonates are disseminated; moderately alkaline (pH 8.4); gradual wavy boundary. (0 to 17 inches thick)
Cy--32 to 48 inches; pale yellow (2.5Y 7/4) clay loam, light olive brown (2.5Y 5/4) moist; moderate very fine and fine angular blocky geogenic structure; very hard, firm, moderately sticky and moderately plastic; few very fine and fine tubular pores; 10 percent channers; few coarse geogenic gypsum crystals; very slightly effervescent (6 percent calcium carbonate equivalent), carbonates are disseminated; strongly alkaline (pH 9.0); gradual wavy boundary. (0 to 16 inches thick)
Cr--48 inches; fractured shale
TYPE LOCATION: Uintah County, Utah; about 1.5 miles west of the Ashley Oil Field; located about 500 feet west and 1,750 feet south of the northeast corner of sec. 21, T.5S., R.22E.; SLBM; Rasmussen Hollow, Utah USGS quad; lat. 40 degrees 22 minutes 17 seconds N. and long. 109 degrees 26 minutes 31 seconds W., NAD 27
RANGE IN CHARACTERISTICS:
Soil moisture: The soil moisture control section is affected by precipitation that falls evenly throughout the year with a slight increase in the late summer and early fall. Typic aridic moisture regime.
Mean annual soil temperature: 47 to 49 degrees F.
Surface rock fragments: 0 to 25 percent gravel
Depth to paralithic contact: 40 to 60 inches to shale or siltstone
Depth to gypsic horizon: 5 to 7 inches
Depth to gypsiferous material: 5 to 7 inches
Particle-size control section: 27 to 35 percent clay, 0 to 15 percent rock fragments, 20 to 30 percent gypsum, 1 to 10 percent calcium carbonate equivalent
A horizon:
Hue: 2.5Y or 10YR
Clay: 10 to 27 percent
Rock fragments: 0 to 15 percent
Calcium carbonate equivalent: 10 to 20 percent
EC (mmhos/cm): 2 to 8
Gypsum: 1 to 3 percent
Reaction: moderately alkaline or strongly alkaline
By horizon:
Hue: 2.5Y or 10YR
Value: 6 to 8 dry
Chroma: 3 or 4 moist
Clay: 27 to 35 percent
Rock fragments: 0 to 20 percent
Calcium carbonate equivalent: 1 to 10 percent
EC (mmhos/cm): 2 to 8
Gypsum: The upper part ranges from 40 to 60 percent and the lower part ranges from 10 to 40 percent.
Cy horizon:
Clay: 27 to 35
Rock fragments: 0 to 15 percent
Calcium carbonate equivalent: 1 to 10 percent
Reaction: moderately alkaline or strongly alkaline
EC (mmhos/cm): 2 to 8
Gypsum: 10 to 15 percent
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Parent material: slope alluvium and colluvium over residuum derived from shale and siltstone
Landform: hills and structural benches
Slopes: 2 to 20 percent
Elevation: 5,000 to 5,300 feet
Mean annual air temperature: 45 to 47 degrees F.
Mean annual precipitation: 5 to 8 inches
Frost-free period: 110 to 125 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Greybull and Hanksville series.
Greybull and Hanksville soils occur on hillslopes and are moderately deep.
DRAINAGE AND PERMEABILITY: Well drained, medium or high runoff, moderately slow permeability.
USE AND VEGETATION: These soils are principally used for rangeland, wildlife habitat and recreation. Potential native vegetation consists of shadscale, Indian ricegrass, galleta, globe mallow and bud sagebrush. This soil has been correlated to a Desert Loam (Shadscale) - 034XY106UT range site in Utah.
DISTRIBUTION AND EXTENT: Northeastern 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 comes from a geographic location in the survey area.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Particle-size control section: The zone from 10 to 40 inches. (By1, By2, By3, By4, and Cy horizons)
Ochric epipedon: The zone from 0 to 5 inches. (A1 and A2 horizons)
Gypsic horizon: The zone from 5 to 32 inches. (By1, By2, By3 and By4 horizons)
Paralithic contact: The contact with weathered shale bedrock at 48 inches. (Cr 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.
ADDITIONAL DATA: Electrical conductivity (mmhos/cm) and percent gypsum were determined by the Soil, Plant and Water Laboratory at Utah State University. Calcium carbonate equivalent was determined by field calcimeter.