LOCATION FAIRBURN SD+NEEstablished Series
TAXONOMIC CLASS: Loamy, mixed, superactive, calcareous, mesic, shallow Aridic Ustorthents
TYPICAL PEDON: Fairburn clay loam - on a convex, southeast-facing slope of 22 percent in range. When described the soil was dry throughout. (Colors are for dry soil unless otherwise stated)
A--0 to 4 inches; brown (10YR 5/3) clay loam, dark grayish brown (10YR 4/2) moist; weak very fine granular structure; soft, very friable, slightly sticky and slightly plastic; slight effervescence; moderately alkaline; clear smooth boundary. (3 to 5 inches)
AC--4 to 10 inches; grayish brown (10YR 5/2) clay loam, dark grayish brown (10YR 4/2) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; strong effervescence; moderately alkaline; clear wavy boundary. (0 to 8 inches)
C--10 to 15 inches; light brownish gray (2.5Y 6/2) clay loam, grayish brown (2.5Y 5/2) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; 10 percent very fine grain sandstone fragments by volume; strong effervescence; strongly alkaline; clear wavy boundary.
Cr--15 to 60 inches; light gray (2.5Y 7/2) weathered very fine-grained sandstone, light brownish gray (2.5Y 6/2) moist; strong effervescence.
TYPE LOCATION: Pennington County, South Dakota; about 7 miles southeast of Scenic; 2300 feet north and 900 feet east of the southwest corner of section 5, T. 4 S., R. 14 E.
RANGE IN CHARACTERISTICS: The control section contains 18 to 35 percent clay. The depth to bedrock ranges from 10 to 20 inches. The depth to carbonates ranges from 0 to 4 inches. The EC ranges from 0 to 2 mmhos/cm throughout.
The A horizon has hue of 10YR or 2.5Y, value of 4 to 7 and 3 to 6 moist, and chroma of 1 to 4. It is silty clay loam, clay loam, loam, or silt loam. Reaction is neutral to moderately alkaline. Some pedons have up to 30 percent by volume of rock fragments.
The AC horizon has hue of 10YR, 2.5Y or 5Y, value of 4 to 7 and 3 to 6 moist, and chroma of 2 to 4. It is silty clay loam, clay loam, loam or silt loam. Reaction is slightly alkaline or moderately alkaline.
Some pedons have Bw horizons less than 6 inches thick with properties similar to the AC horizon.
The C horizon has hue of 10YR, 2.5Y or 5Y, value of 4 to 8 and 3 to 7 moist, and chroma of 2 to 4. It is silty clay loam, clay loam, loam or silt loam. Fragments of siltstone or mudstone ranges from 0 to 15 percent by volume. Reaction ranges from slightly alkaline to strongly alkaline.
The Cr horizon has hue of 10YR, 2.5Y, or 5Y. Reaction is moderately alkaline or strongly alkaline. It is very fine-grained sandstone, siltstone, shale or mudstone.
COMPETING SERIES: These are the Dolcan, Menefee, Mittenbutte (T), Sipapu, Spearfish series. Dolcan soils occur at elevations above 6,200 feet and have precipitation that is distributed evenly throughout the year. Menefee soils have Bw horizons more than 6 inches thick. Mittenbutte soils contain less than 18 percent clay in the particle-size control section. Sipapu and Spearfish soils have hues of 7.5YR or redder below the A horizon. In addition, Sipapu soils have more than 15 percent pararock fragments in the particle-size control section.
GEOGRAPHIC SETTING: Fairburn soils are on gently sloping to very steep upland hills and ridges. Slopes generally are convex and range from 3 to 60 percent. The soil formed in residuum weathered from siltstone, very fine-grained sandstone, shale or mudstone. Mean annual air temperature ranges from 43 to 50 degrees F. Mean annual precipitation ranges from 12 to 18 inches, most of which occurs in the spring and early summer. Elevation ranges from 2,600 to 5,800 feet. Frost-free period ranges from 105 to 150 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Blackpipe, Metre, Norrest, Orella and Wortman soils. The Blackpipe, Metre, Norrest and Wortman soils have mudstone or shale at a depth below 20 inches and their particle-size control section contain more than 35 percent clay. In addition, the Blackpipe, Metre and Wortman soils have a mollic epipedon. They are on less sloping parts of the landscape below the Fairburn soils. Orella soils are on similar parts of the landscape as the Fairburn soils. Orella soils have a fine textured control section.
DRAINAGE AND PERMEABILITY: Well drained. Runoff is medium or high depending on slope. Permeability is moderate or moderately slow.
USE AND VEGETATION: Used primarily as rangeland. Native vegetation includes threadleaf sedge, needleleaf sedge, sideoats grama, blue grama, western wheatgrass, green needlegrass, yucca, and pricklypear.
DISTRIBUTION AND EXTENT: Southwestern South Dakota. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Pennington County, South Dakota, 1985.
REMARKS: Diagnostic horizons and features recognized in this pedon are: ochric epipedon - the zone from the surface of the soil to a depth of about 4 inches (A horizon).