LOCATION BRONELL COEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Ustic Haplocalcids
TYPICAL PEDON: Bronell very gravelly loam - on a 35 percent convex north-facing slope in an area of chained pinyon and juniper. (Colors are for dry soil unless otherwise noted.)
A--0 to 6 inches; grayish brown (10YR 5/2) very gravelly loam, dark grayish brown (10YR 4/2) moist; moderate coarse granular structure; soft, very friable, slightly sticky, and nonplastic; 45 percent pebbles, 5 percent cobbles; strongly effervescent; moderately alkaline; abrupt smooth boundary. (3 to 7 inches thick)
Bk1--6 to 11 inches; light brownish gray (10YR 6/2) very gravelly sandy clay loam, grayish brown (10YR 5/2) moist; weak medium subangular blocky structure; slightly hard, friable, sticky, and slightly plastic; 45 percent pebbles; 5 percent cobbles; violently effervescent; moderately alkaline; clear smooth boundary (3 to 12 inches)
Bk2--11 to 20 inches; pinkish gray (7.5YR 7/2) extremely gravelly sandy clay loam, brown (7.5YR 5/2) moist; massive; hard, friable, sticky, and slightly plastic; 55 percent pebbles, 5 percent cobbles; violently effervescent; many fine irregularly shaped soft masses of secondary calcium carbonate; moderately alkaline; clear wavy boundary. (0 to 30 inches thick)
Bk3--20 to 40 inches; pinkish gray (7.5YR 6/2) very gravelly sandy clay loam, brown (7.5YR 5/2) moist; massive; hard, friable, sticky, and slightly plastic; 50 percent pebbles; violently effervescent; finely divided secondary calcium carbonate disseminated throughout and coating rock fragments; moderately alkaline; gradual wavy boundary. (0 to 15 inches thick)
Bk4--40 to 60 inches; pinkish gray (7.5YR 6/2) extremely gravelly sandy loam, brown (7.5YR 5/2) moist; massive; hard, friable, sticky, and slightly plastic; 60 percent pebbles; violently effervescent; many large somewhat rounded soft masses of secondary calcium carbonate; moderately alkaline. (10 to 45 inches thick)
TYPE LOCATION: Fremont County, Colorado; about 1 mile from U.S. Highway 50 in roadcut along Kerr Gulch Road; 1,600 feet south and 500 feet west of the northeast corner of Sec. 24, T. 48 N., R. 10 E. U.S.G.S. Howard quad.; Lat. 38 degrees, 23 minutes, 58 seconds N., and Long. 105 degrees, 48 minutes, 03 seconds W.
RANGE IN CHARACTERISTICS: Mean annual soil temperature ranges from 43 to 47 degrees F., and mean summer soil temperature ranges from 59 to 65 degrees F. The depth to secondary calcium carbonate is 6 to 15 inches. The moisture control section is dry in most years in some part; more than one-half the time the soil temperature at a depth of 20 inches is above 41 degrees F. However, in most years it is moist in some part for 60 or more consecutive days in early spring, summer, and early fall. It is also dry for less than 60 cumulative days during the first 90 days following the winter solstice. About equal amounts of precipitation are received each month while the soil temperature is greater than 41 degrees F. Rock fragment content of the particle-size control section ranges from 30 to 65 percent pebbles, 0 to 20 percent cobbles, and 0 to 15 percent stones.
The A horizon has hue of 2.5Y through 7.5YR, value of 5 or 6 dry, 3 through 5 moist, and chroma of 2 through 4. It is slightly alkaline or moderately alkaline.
The Bk horizons have hue of 2.5Y through 7.5YR, value of 6 through 8 dry, 5 through 7 moist, and chroma of 2 through 4. It generally has a calcium carbonate equivalent content greater than 20 percent, but ranges from 15 to 40 percent. The fine earth fraction is sandy clay loam or sandy loam, but thin strata of loam also are present in some pedons. Clay content ranges from 18 to 27 percent in the particle-size control section, silt from 10 to 40 percent, and total sand content is 45 to 65 percent. Sand is mainly fine or coarser sand.
COMPETING SERIES: These are the Barkelew (CO), Brownsto (WY), Browtine (WY), and Bruja (WY) series. Barkelew soils have 27 to 35 percent clay in the particle-size control section and have a cambic horizon. Brownsto soils in most years receive a greater proportion of total precipitation when the soil temperature is less than 41 degrees F. Bruja soils have a paralithic contact at 20 to 40 inches.
GEOGRAPHIC SETTING: Bronell soils are on terraces, mountainsides, ridges and toe slopes and foot slopes. Slopes range from 2 to 60 percent. The soils formed in alluvium. Strata are of variable thickness and texture, and include weakly cemented conglomerate with fragments of volcanic rocks. Elevation ranges from 6,500 to 8,400 feet. The mean annual temperature ranges from 41 to 45 degrees F., and the mean annual precipitation ranges from 11 to 16 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Kerhayden and Mussel soils. Kerhayden and Mussel soils average less than 35 percent by volume rock fragments in the family particle-size control section and lack a calcic horizon.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; moderately rapid permeability.
USE AND VEGETATION: These soils are used for livestock grazing and noncommercial woodland. Firewood is harvested from these areas. Pinyon and juniper have been chained off many areas to improve grass production. Principal vegetation in unchained areas is an open-to-moderately dense stand of pinyon and Rocky Mountain juniper and an understory of blue grama, western wheatgrass, mountain muhly, little bluestem, mountain mahogany, and other forbs and shrubs.
DISTRIBUTION AND EXTENT: Foothills of "east slope", southern Rocky Mountains of central and south-central Colorado. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Fremont County (Fremont County Area), Colorado, 1988.
REMARKS: This revision updates the classification from a Borollic Calciorthids to be compatible to the 1994 Amendments to Soil Taxonomy. Diagnostic horizons and features recognized in this soil include an ochric epipedon from 0 to 6 inches; and a calcic horizon from 6 to 60 inches; over 35 percent rock fragments in the texture control section. It has an ustic aridic moisture regime and a frigid temperature regime. Last updated by the state 8/95.
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.