LOCATION UNAWEEP COEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, frigid Typic Haplustolls
TYPICAL PEDON: Unaweep fine sandy loam, on a north facing, alluvial fan, 5 percent slope in grassland at an elevation of 6780 feet. (Colors are for dry soil unless otherwise noted.)
A1--0 to 4 inches; grayish brown (10YR 5/2) fine sandy loam, very dark grayish brown (10YR 3/2) moist; moderate very fine granular structure; soft, very friable, nonsticky and nonplastic; noneffervescent; neutral (pH 7.0); many fine and very fine roots; clear wavy boundary. (3 to 6 inches thick)
A2--4 to 10 inches; brown (7.5YR 5/3) fine sandy loam, dark brown (7.5YR 3/3) moist; weak coarse subangular blocky structure parting to fine granular; slightly hard, very friable, nonsticky and nonplastic; approximately 5 percent sandstone gravels; noneffervescent; neutral (pH 7.2); common fine and coarse roots between peds; clear smooth boundary. (4 to 10 inches thick)
Bw--10 to 18 inches; reddish brown (5YR 5/3) fine sandy loam, reddish brown (5YR 4/3) moist; weak medium subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; 10 percent sandstone gravels; noneffervescent; neutral (pH 7.2); common fine and coarse roots between peds; gradual wavy boundary. (0 to 13 inches thick)
Bk--18 to 44 inches; reddish brown (5YR 5/4) fine sandy loam, reddish brown (5YR 4/3) moist; weak fine subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; few fine roots in cracks; few fine soft carbonate threads throughout; strongly effervescent; slightly alkaline (pH 7.6); 10 percent sandstone gravels; gradual smooth boundary. (15 to 40 inches)
C--44 to 60 inches; reddish brown (5YR 5/3) fine sandy loam, reddish brown (5YR 4/3) moist; massive; slightly hard, very friable, nonsticky and nonplastic; 10 percent sandstone gravels; strongly effervescent; moderately alkaline (pH 8.0).
TYPE LOCATION: Mesa County, Colorado; about 14 miles southwest of Whitewater, on a north facing, alluvial fan, 5 percent slope in rangeland at an elevation of 6780 feet; located about 1500 feet west and 2400 feet north of the southeast corner of section 20, T. 14 S., R. 100 W.; USGS Jacks Canyon topographic quadrangle; lat. 38 degrees 49 minutes 18 seconds N. and long. 108 degrees 35 minutes 40 seconds W., NAD 1927.
RANGE IN CHARACTERISTICS:
Soil moisture regime: Ustic
Soil temperature regime: Frigid
Mean annual soil temperature: 43 to 46 degrees F
Mean annual summer soil temperature: 66 to 68 degrees F
Particle-size control section: 8 to 18 percent clay
Depth to secondary calcium carbonate: 15 to 30 inches
Thickness of the mollic epipedon: 7 to 16 inches
A horizon:
Hue: 10YR to 5YR
Value: 4 or 5 dry and 2 or 3 moist
Chroma: 2 or 3
Reaction: Neutral or slightly alkaline
Bw horizon, if present:
Hue: 5YR or 2.5YR
Value: 5 or 6 dry and 4 or 5 moist
Chroma: 2 to 4
Reaction: Neutral or slightly alkaline
Bk horizon:
Hue: 7.5YR to 2.5YR
Value: 5 or 6 dry and 4 or 5 moist
Chroma: 2 to 4
Reaction: Slightly alkaline or moderately alkaline
C horizon:
Hue: 7.5YR to 2.5YR
Value: 5 or 6 dry and 4 or 5 moist
Chroma: 2 to 4
Reaction: Slightly alkaline or moderately alkaline
COMPETING SERIES: These are the Baggs (MT), Baxton (MT), Belain (MT), Bitterroot (MT), Chincap (WY), Hopley (MT), Mott (ND), Panguitch (UT), Relan (MT), Tally (MT), Vebar (ND), Victor (MT), and Weedzunit (MT) series. Baggs soils are non-calcareous throughout. Baxton and Hopley soils are deep and have bedrock between 40 and 60 inches. Bitterroot, Chincap, Vebar, Weedzunit, and Belain soils have bedrock between 20 and 40 inches. Panguitch soils have a calcic horizon. Mott and Victor soils have sandy or sandy skeletal substratums. Relan and Tally soils receive the major part of their precipitation during the summer.
GEOGRAPHIC SETTING: Unaweep soils.
Parent material: Alluvium derived from sandstone with minor amounts of igneous rocks.
Landform: Alluvial fans and valley floors.
Slopes: 0 to 20 percent
Elevation: 6000 to 7200 feet
Mean annual air temperature: 43 to 46 degrees F
Mean annual precipitation: 14 to 16 inches.
Wettest months: August and September.
Driest months: May, June, and July.
Frost-free period: 75 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Nelman and Loma series. Nelman soils lack a mollic epipedon, and Loma soils have and argillic horizon.
DRAINAGE AND PERMEABILITY: Well drained, slow runoff, moderately rapid permeability.
USE AND VEGETATION: These soils are used principally as native pastureland, although they are irrigated in areas where water is available. Native vegetation is sage and western wheatgrass.
DISTRIBUTION AND EXTENT: The western slopes of Colorado. LRR E, MLRA 48A. This series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Mesa County (Lower Colorado Area), Colorado 1970 The name is taken from a landmark in the area.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon: The zone from 0 to 10 inches. (The zone of organic matter accumulation and high base saturation from the soil surface to a depth of 10 inches.)
Cambic horizon: The zone from 10 to 18 inches. (A zone of alteration)
Taxonomy Version: Seventh Edition, 1996
ADDITIONAL DATA: The Unaweep series is being re-classified. Unaweep was formerly classified as an Aridic Haplustoll.