LOCATION BROKENHORN WYEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Ustic Calcigypsids
TYPICAL PEDON: Brokenhorn clay loam--rangeland. (Colors are for dry soil unless otherwise stated.)
A--0 to 1 inch; light brownish gray (10YR 6/2) clay loam, dark grayish brown (10YR 4/2) moist; moderate fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; many fine roots; strongly effervescent, carbonates disseminated; moderately alkaline (pH 8.0); clear smooth boundary. (1 to 4 inches thick)
Bw--1 to 4 inches; light brownish gray (10YR 6/2) clay loam, dark grayish brown (10YR 4/2) moist; moderate coarse prismatic structure parting to moderate medium subangular blocky; hard, firm, slightly sticky and slightly plastic; many fine roots; strongly effervescent, carbonates disseminated; moderately alkaline (pH 8.2); clear smooth boundary. (0 to 7 inches thick)
Bk1--4 to 10 inches; brown (10YR 5/3) clay loam, dark brown (10YR 4/3) moist; weak medium prismatic structure parting to weak fine subangular blocky; hard, firm, slightly sticky and slightly plastic; common fine roots; violently effervescent, carbonates disseminated and as common fine cylindrical soft masses in root channels, 18 percent calcium carbonate equivalent; moderately alkaline (pH 8.2); diffuse wavy boundary.
Bk2--10 to 26 inches; light brownish gray (10YR 6/2) clay loam, dark grayish brown (10YR 4/2) moist; massive; hard, friable, sticky and plastic; common fine roots; violently effervescent, carbonates disseminated and as common fine cylindrical soft masses in root channels, 27 percent calcium carbonate equivalent; moderately alkaline (pH 8.2); diffuse wavy boundary.
Bk3--26 to 32 inches; grayish brown (2.5YR 5/2) clay, dark grayish brown (2.5Y 4/2) moist; massive; very hard, very
firm, sticky and plastic; few fine roots; violently effervescent, carbonates disseminated and as common fine cylindrical soft masses in root channels, 28 percent calcium carbonate equivalent; strongly alkaline (pH 8.6); diffuse wavy boundary. (Combined thickness of the Bk horizon is 12 to 34 inches)
By--32 to 60 inches; grayish brown (2.5Y 5/2) clay, dark grayish brown (2.5Y 4/2) moist; weak thin platy shale rock structure; hard, firm, sticky and plastic; violently effervescent, carbonates disseminated, 20 percent calcium carbonate equivalent; common fine seams and filaments of gypsum, 10 percent gypsum; moderately alkaline (pH 8.4).
TYPE LOCATION: Natrona County, Wyoming; about 5.5 miles ESE of the Willow Creek School; 400 feet west and 1,500 feet north of the SE corner of sec. 15, T. 40 N., R. 82 W.
RANGE IN CHARACTERISTICS: Depth to continuous accumulation of carbonates is 1 to 8 inches. Depth to continuous accumulation of gypsum is 20 to 38 inches. The particle size control section is clay loam or clay with 35 to 50 percent clay. The weighted average organic carbon content in the upper soil to a depth of 40 cm ranges from 1 to 2 percent. The mean annual soil temperature is 50 to 52 degrees F.
The A horizon has value of 5 or 6 dry, 4 or 5 moist and chroma of 2 or 3. EC is less than 2 mmhos.
The Bw horizon has value of 5 or 6 dry, 4 or 5 moist and chroma of 2 or 3.
The Bk horizon has hue of 10YR or 2.5Y, value of 5 or 6 dry, 4 or 5 moist and chroma of 2 or 3. Calcium carbonate equivalent ranges from 15 to 37 percent. EC ranges from 2 to 4 mmhos. It is moderately alkaline or strongly alkaline.
The By horizon has hue of 10YR or 2.5Y, value of 5 through 7 dry, 4 or 5 moist, and chroma of 1 through 3. Calcium carbonate equivalent ranges from 10 to 25 percent. Gypsum ranges from 5 to 15 percent. EC ranges from 4 to 8 mmhos. It is moderately alkaline or strongly alkaline.
COMPETING SERIES: The Hyshot series. Hyshot soils are moderately deep.
GEOGRAPHIC SETTING: Brokenhorn soils are on gently rolling uplands. They formed in local alluvium and residuum derived from gypsiferous shale. Slopes range from 2 to 12 percent. Elevation is 5,000 to 5,800 feet. The mean annual precipitation is 10 to 14 inches, and the mean annual temperature is 46 to 51 degrees F. The frost-free season is 110 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cavegulch and the competing Hyshot soils. Cavegulch soils do not have a calcic horizon and are fine-silty.
DRAINAGE AND PERMEABILITY: Well drained; medium or rapid runoff; slow permeability.
USE AND VEGETATION: These soils are used for livestock grazing and wildlife habitat. Vegetation is mainly green needlegrass, western wheatgrass, and big sagebrush.
DISTRIBUTION AND EXTENT: Central Wyoming. The series is of limited extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Natrona County, Wyoming; 1985.