LOCATION BUNKWATER CO+UT WYEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Ustic Natrargids
TYPICAL PEDON: Bunkwater very fine sandy loam-rangeland. (Colors are for dry soil unless otherwise noted).
E--0 to 2 inches; pink (7.5 YR 7/4) very fine sandy loam, brown (7.5YR 4/4) moist; moderate fine platy structure parting to weak fine granules; slightly hard, very friable, nonsticky and nonplastic; moderately alkaline (pH 8.2); abrupt smooth boundary. (2 to 6 inches thick)
Btn--2 to 7 inches; reddish brown (5YR 5/4) clay loam, reddish brown (5YR 4/4) moist; moderate medium columnar structure parting to moderate medium subangular blocks; hard, friable, sticky and plastic; common distinct clay films on faces of peds; strongly alkaline (pH 8.5); clear smooth boundary. (3 to 7 inches thick)
Btkn--7 to 13 inches; light reddish brown (5YR 6/4) clay loam, reddish brown (5YR 4/4) moist; moderate fine subangular blocky structure; hard, friable, sticky and plastic; common distinct clay films on faces of peds; strongly effervescent, common medium calcium nodules; very strongly alkaline (pH 9.2); clear wavy boundary. (6 to 16 inches thick)
Bkn--13 to 33 inches; light reddish brown (5YR 6/4) clay loam, reddish brown (5YR 5/4) moist; weak medium subangular blocky structure; hard, friable, sticky and plastic; strongly effervescent, many fine calcium nodules; very strongly alkaline (pH 9.4); clear wavy boundary. (0 to 20 inches thick)
Bk1--33 to 42 inches; light brown (7.5YR 6/4) clay loam, brown (7.5YR 5/4) moist; massive; slightly hard, friable, sticky and plastic; violently effervescent, few fine calcium nodules; very strongly alkaline (pH 9.4); gradual wavy boundary. (0 to 20 inches thick)
Bk2--42 to 60 inches; light brown (7.5YR 6/4) silty clay loam, brown (7.5YR 5/4) moist; massive; slightly hard, friable, sticky and plastic; violently effervescent, few fine calcium nodules; strongly alkaline (pH 9.0).
TYPE LOCATION: Mesa County, Colorado, 2 miles north of Debeque, Colorado; 850 feet east and 200 feet south of the northwest corner, Sec. 15, T. 8 S., R. 97 W. U.S.G.S. Debeque Quad.; Lat. 39 degrees, 21 minutes, 56 seconds N., & Long. 108 degrees, 12 minutes, 41 seconds W.
RANGE IN CHARACTERISTICS: The mean annual soil temperature ranges from 47 to 54 degrees F., and the mean summer soil temperature ranges from 60 to 70 degrees F. The upper portion of the Bt is commonly noncalcareous, but some pedons may be calcareous to the surface. Coarse fragments range from 0 to 15 percent and are typically less than 5 percent.
An A horizon is present in some pedons.
The E horizon has hue of 10YR through 5YR, value of 5 through 7 dry, 4 through 6 moist and chroma of 2 through 4.
The Bt horizon has hue of 7.5YR through 2.5YR, value of 5 or 6 dry, 4 or 5 moist, and chroma of 3 through 6. Texture is clay loam, silty clay loam, or sandy clay loam with clay ranging from 20 to 35 percent. Fifteen to 35 percent of the sand is coarser than very fine sand. Structure is columnar parting to angular or subangular blocky. Reaction is from strongly alkaline in the upper portion to very strongly alkaline in the lower part.
The Bk horizon has hue of 10YR through 5YR. Reaction is strongly alkaline or very strongly alkaline. In some pedons below the particle-size control section or at 36 inches, sandy loams are common.
COMPETING SERIES: These are the Avar (CO), Firstview (CO), and Starlake (NM) series. Avar soils have a natric layer with more than 35 percent clay and the base of the natric horizon is less than or equal to 10 inches below the surface. In addition, they are underlain by buried horizons. Firstview soils have lithologic discontinuities of clay at 20 to 36 inches. Starlake soils have hues of 10YR and yellower in the Bt horizon.
GEOGRAPHIC SETTING: The Bunkwater soils are on dissected upland plateaus and structural benches. Slopes are 1 to 8 percent. These soils formed in aeolian deposits of mixed sources. At the type location the mean annual precipitation is 9 to 16 inches. The mean annual temperature is 45 to 54 degrees F., and the frost-free period is 90 to 150 days. Elevation is 5,000 to 6,000 feet.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Barx and Dominguez soils. Barx soils have a calcic horizon and lack a natric horizon. Dominguez soils have more than 35 percent clay and formed in clayey residuum.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderately slow permeability.
USE AND VEGETATION: These soils are used as native rangeland. The native vegetation is mainly big sagebrush, greasewood, galleta, western wheatgrass, bottlebrush squirreltail, shadscale and Douglas rabbitbrush.
DISTRIBUTION AND EXTENT: Bunkwater soils are of small extent with about 10,000 acres mapped, and occur in the lower Colorado River Plateau region of western Colorado and the northeastern part of Utah.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Mesa County (Douglas-Plateau Survey Area), Colorado, 1988.
REMARKS: Diagnostic horizons and features recognized in this pedon are: ochric epipedon: zone from 0 to 2 inches; natric horizon: zone from 2 to 13 inches; Ustic Aridic moisture regime. This revision updates the classification from an Ustollic Natrargid to an Ustic Natrargid. (1994 Amendments to Soil Taxonomy). Last updated by the state 3/95.
The superactive cation exchange activity class was added in 03/2003 to the taxonomic classification by the National Soil Survey Center on request of the Lakewood MLRA office, without review of the soil series property data. The remainder of this document has not been updated.