LOCATION COBBLETOP WYTentative Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Oxyaquic Argiustolls
TYPICAL PEDON: Cobbletop fine sandy loam on a northeast facing slope of 1 percent in irrigated hayland at an elevation of 7,315 feet. (Colors are dry soil unless otherwise stated). When described on 7/3/2003, the soil was moist from 0 to 14 inches.
Ap--0 to 4 inches; very dark grayish brown (10YR 3/2) sandy loam, very dark brown (10YR 2/2) moist; weak fine granular structure; soft, very friable; nonsticky and nonplastic; many very fine and fine roots; many fine interstitial pores; 6 percent gravel; non-effervescent; neutral (pH 7.2); clear smooth boundary. (2 to 6 inches thick)
Bt--4 to 14 inches; dark brown (7.5YR 3/2) very gravelly sandy clay loam, very dark brown (7.5YR 2.5/2) moist; moderate medium prismatic structure parting to moderate fine and medium subangular blocky; slightly hard, friable; slightly sticky and slightly plastic; common very fine and fine roots; common fine tubular pores; common discontinuous distinct very dark brown (10YR 2/2) clay films on faces of peds; 40 percent gravel and 10 percent cobbles; non-effervescent; common very fine and fine distinct strong brown (7.5YR 4/6) redox concentrations; neutral (pH 7.2); gradual smooth boundary. (4 to 16 inches thick)
Bk1--14 to 25 inches; reddish brown (5YR 4/4) extremely cobbly sandy loam, dark reddish brown (5YR 3/4) moist; single grain; loose, loose; few very fine and fine roots; few fine interstitial pores; 25 percent gravel, 35 percent cobbles, and 5 percent stones; carbonates are disseminated; slightly effervescent; slightly alkaline (pH 7.4); gradual smooth boundary. (6 to 26 inches thick)
Bk2--25 to 80 inches; reddish brown (5YR 5/3) extremely cobbly loamy sand, reddish brown (5YR 4/3) moist; single grain; loose, loose; few very fine and fine roots; few fine interstitial pores; 30 percent gravel, 40 percent cobbles, and 5 percent stones; carbonates are disseminated; slightly effervescent; slightly alkaline (pH 7.4).
TYPE LOCATION: Uinta County, Wyoming; about 1.5 miles northwest of Robertson; about 2200 feet east and 2400 feet north of the southwest corner of sec. 13, T. 14 N., R. 116 W. Robertson, USGS quadrangle lat. 41 degrees, 11 minutes, 32 seconds north, long. 110 degrees, 26 minutes, 29 seconds west NAD83.
RANGE IN CHARACTERISTICS:
Depth to the base of the argillic horizon: 8 to 20 inches
Mollic epipedon thickness: 7 to 15 inches
Depth to calcium carbonate: 22 to 60 inches
Depth to irrigation induced episaturation Top depth 0 to 14 inches, Bottom depth 14 to 36 inches
Soil temperature: 41 to 45 degrees F
Particle-size control section the Bt horizon
Soil moisture: The moisture control section is usually dry, but is moist in some parts for 30 to 50 cumulative days between May 10 and October 10. Ustic moisture regime bordering on aridic.
A horizon
Hue: 10YR, 7.5YR or 5YR
Value: 3 to 5 dry, 2 or 3 moist
Chroma: 1 to 3
Texture: sandy loam or fine sandy loam
Rock fragments: 0 to 6 percent0 to 6 percent gravel, 0 to 5 percent cobble
Reaction: 6.6 to 7.3 neutral
Electrical conductivity: 0 to 2 mmhos/cm
Bt horizon:
Hue: 10 YR, 7.5YR, or 5YR
Value: 3 to 5 dry, 2 to 4 moist
Chroma: 2 to 3
Redox concentrations: few to common distinct or prominent
Texture: very gravelly or very cobbly sandy clay loam or clay loam
Clay content: 20 to 35 percent
Rock fragments: 35 to 55 percent10 to 40 percent gravel, 10 to 30 percent cobble, 0 to 5 percent stones
Reaction: 7.4 to 7.8 slightly alkaline
Electrical conductivity: 0 to 2 mmhos/cm
Bk1 horizon
Hue: 7.5YR or 5YR
Value: 4 to 5 dry, 3 to 4 moist
Chroma: 3 to 4
Texture: very or extremely gravelly or very or extremely cobbly sandy loam or loamy sand
Rock fragments: 35 to 70 percent15 to 40 percent gravel, 20 to 40 percent cobble, 0 to 10 percent stones
Reaction: 7.4 to 7.8 slightly alkaline
Electrical conductivity: 0 to 2 mmhos/cm
Bk2 horizon
Hue: 7.5YR or 5YR
Value: 4 to 5 dry, 3 to 4 moist
Chroma: 3 to 4
Texture: extremely gravelly or extremely cobbly loamy sand or sand
Rock fragments: 35 to 75 percent 30 to 55 percent gravel, 35 to 60 percent cobble, 0 to 10 percent stones
Reaction: 7.4 to 7.8 slightly alkaline
Electrical conductivity: 0 to 2 mmhos/cm
COMPETING SERIES: There are no other series currently recognized in this family.
These are the Bazoo and Fortsupply series.
Bazoo and Fortsupply soils have fine-loamy control sections.
Fortsupply soils have accumulations of secondary calcium carbonate at depths of 8 to 22 inches.
GEOGRAPHIC SETTING:
Landform: (strath) stream terraces
Parent material: alluvium
Elevation: 6,200 to 7,400 feet
Slope: 0 to 6 percent
Mean annual precipitation: 9 to 14 inches
Mean annual air temperature: 39 to 43 degrees F.
Frost-free period: 60 to 90 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Millburne, Robertson and Urie series. Millburne and Robertson soils occur on similar positions as Cobbletop but have fine-loamy control sections and calcic horizons with petronodes at depths greater than 10 inches. Urie soils have a calcic horizon with petronodes at depths greater than 10 inches.
DRAINAGE AND PERMEABILITY: moderately well or somewhat poorly drained due to flood irrigation. Permeability is moderate in the upper part and rapid in the lower part of the solum. Runoff is negligible to low.
USE AND VEGETATION: These soils are used principally as irrigated hayland and pasture. Principal vegetation includes garrison creeping foxtail, sedge, rush, big sage, Sandberg bluegrass and western wheatgrass.
DISTRIBUTION AND EXTENT: Present known distribution limited to the southwestern part of Wyoming. MLRA34A. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: The Soil Survey of Uinta County, Wyoming, 2004. Series name is coined.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon 0 to 10 inches (A, Bt)
Argillic horizon 4 to 14 inches (Bt)
Redoximorphic concentrations 4 to 20 inches (Bt, Bk1)
Episaturation 0 to 16 inches (A, Bt, Bk1)
Solum is recharged by carbonates due to irrigation