LOCATION ROBIDO UTEstablished Series
TAXONOMIC CLASS: Coarse-loamy, siliceous, superactive, mesic Cumulic Haplustolls
TYPICAL PEDON: Robido fine sandy loam -- rangeland. (Colors are for air-dry soil unless otherwise stated.)
A1--0 to 3 inches; brown (7.5YR 5/3) fine sandy loam, dark brown (7.5YR 3/2) moist; weak very fine and fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and fine, common medium roots; common very fine, few fine interstitial and tubular pores; moderately alkaline (pH 8.0); abrupt smooth boundary. (3 to 9 inches thick).
A2--3 to 8 inches; brown (7.5YR 5/3) loam, dark brown (7.5YR 3/2) moist; few fine distinct strong brown (7.5YR 5/8) redoximorphic concentrations; moderate very fine and fine subangular blocky structure; hard, friable, slightly sticky and slightly plastic; many very fine and fine, common medium and coarse roots; many very fine and fine, common medium, few coarse tubular pores; moderately alkaline (pH 8.0); abrupt smooth boundary. (0 to 9 inches thick).
C1--8 to 24 inches; brown (7.5YR 5/4) sandy loam, dark brown (7.5YR 3/3) moist; weak fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and nonplastic; common very fine, few fine, medium and coarse roots; common very fine, few fine interstitial and tubular pores; many medium distinct dark yellowish brown (10YR 4/6) redoximorphic concentrations; moderately alkaline (pH 7.9); abrupt wavy boundary. (7 to 16 inches thick).
C2--24 to 29 inches; brown (7.5YR 5/3) fine sandy loam, dark brown (7.5YR 3/2) moist; weak fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine, few fine, medium and coarse roots; many very fine, common fine tubular pores; many medium distinct yellowish brown (10YR 5/6) redoximorphic concentrations; moderately alkaline (pH 7.9); gradual wavy boundary. (0 to 17 inches thick).
2C3--29 to 39 inches; light brown (7.5YR 6/4) extremely cobbly sand, brown (7.5YR 4/3) moist; single grain; loose, nonsticky and nonplastic; many very fine and fine, common medium and coarse roots; common very fine interstitial pores; 20 percent gravel, 45 percent cobbles, 5 percent stones; common fine distinct brownish yellow (10YR 6/8) redoximorphic concentrations; slightly alkaline (pH 7.7); gradual smooth boundary. (6 to 16 inches thick).
2C4--39 to 51 inches; light brown (7.5YR 6/4) extremely cobbly sand, brown (7.5YR 4/3) moist; single grain; loose, nonsticky and nonplastic; few very fine and fine, common medium and coarse roots; common very fine and fine interstitial pores; 50 percent gravel, 20 percent cobbles, 5 percent stones; common fine distinct brownish yellow (10YR 6/8) redoximorphic concentrations; slightly alkaline (pH 7.7); gradual smooth boundary. (8 to 21 inches thick).
2C5--51 to 60 inches; light brown (7.5YR 6/3) extremely cobbly sand, brown (7.5YR 4/3) moist; single grain; loose, nonsticky and nonplastic; few very fine and fine, common medium and coarse roots; common very fine and fine interstitial pores; 30 percent gravel, 40 percent cobbles, 5 percent stones; few fine distinct brownish yellow (10YR 6/6) redoximorphic concentrations; slightly alkaline (pH 7.8).
TYPE LOCATION: Uintah County, Utah; 4 miles north of Fort Duchesne on the Fort Duchesne, Utah USGS quadrangle; 1,400 feet north, 700 feet west of the southeast corner of sec. 34 , T.1S., R.2E., USBM; 40 degrees, 20 minutes, 59 seconds north latitude and 109 degrees, 51 minutes, 41 seconds west longitude; NAD 027.
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 fall. The soil moisture regime is aridic bordering on ustic.
Mean annual soil temperature ranges from 47 to 51 degrees F.
Depth to endosaturation: 20 to 40 inches during the months of March through July. Meltwater is the source of occassional very long duration flooding.
Depth to lithologic discontinuity: 24 to 32 inches to sandy-skeletal materials.
Thickness of the mollic epipedon: 20 to 32 inches.
Particle-size control section (weighted average): 5 to 17 percent clay and 15 to 35 percent rounded rock fragments
A horizon:
Hue: 7.5 YR or 10YR
Value: 4 or 5 dry, 2 or 3 moist
C horizon:
Value: 4 or 5 dry, 3 or 4 moist
Chroma: 2 to 4 dry or moist
Texture: commonly fine sandy loam and sandy loam with strata of loam or loamy fine sand in some pedons
Calcium carbonate equivalent: 0 to 2 percent
Reaction: slightly alkaline or moderately alkaline
2C horizon:
Value: 5 to 7 dry, 3 to 6 moist
Chroma: 3 or 4 dry or moist
Texture: commonly extremely cobbly sand or extremely cobbly loamy sand with strata of extremely gravelly fine sandy loam or extremely gravelly loamy fine sand in some pedons
Rock fragments: rounded from quartzite and sandstone
Calcium carbonate equivalent: 0 to 2 percent
Reaction: slightly alkaline or moderately alkaline
COMPETING SERIES: There are no competing series in this family.
GEOGRAPHIC SETTING:
Parent material: alluvium derived from sedimentary and metamorphic rocks
Landform: flood plains
Slopes: 1 to 4 percent
Elevation: 4,700 to 6,400 feet
Mean annual precipitation: 7 to 12 inches
Mean annual air temperature: 45 to 49 degrees F.
Freeze-free period: 110 to 140 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Uver, Heapo, and Paradox soils. Uver soils are sandy-skeletal. Heapo soils are sandy-skeletal and have a cambic horizon. Paradox soils are fine-loamy and on alluvial flats.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; very low runoff; moderately rapid permeability.
USE AND VEGETATION: These soils are used principally for rangeland, woodland, wildlife habitat, and recreation. Potential vegetation consists of bluegrass, wheatgrass, coyote willow, basin big sagebrush, rubber rabbitbrush, and narrowleaf cottonwood. This soil has been correlated to the Semiwet Streambank (Narrowleaf Cottonwood) - 034XY019UT range site in Utah.
DISTRIBUTION AND EXTENT: Northeastern Utah. LRR D, MLRA 34. The 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 coined from the first Utah Trading Post, Fort Robidoux.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Particle-size control section: The zone from 10 to 40 inches. (C1, C2, 2C3, and 2C4 horizons)
Mollic epipedon: The zone from the surface to 29 inches. (A1, A2, C1, and C2 horizons)
Lithologic discontinuity: The contact with sandy-skeletal material (dominated by cobbles) at the upper boundary of the 2C3 horizon.
Endosaturation: The zone of saturation from 20 to 40 inches during the months of March through July.
The particle-size control section placement is not coarse-loamy over sandy or sandy skeletal because the coarse-loamy material contains more than 50 percent fine or coarser sand. The weighted average percent rock fragments for most pedons is 30 to 35 percent.
The SEC activity class was inferred from laboratory data from similar soils in the Uintah Area Soil Survey.
Taxonomic version: Eighth Edition, 1998.