LOCATION REDBIRD SDEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Pachic Argicryolls
TYPICAL PEDON: Redbird silt loam - on a north-facing slope of 2 percent under native grassland at an elevation of 6540 feet. When described, the soil was dry throughout. (Colors are for dry soil unless otherwise noted).
A1--0 to 3 inches; dark grayish brown (10YR 4/2) silt loam, very dark brown (10YR 2/2) moist; weak fine and medium granular structure; slightly hard, very friable; 5 percent by volume of fragments of rock; neutral; clear smooth boundary.
A2--3 to 7 inches; dark grayish brown (10YR 4/2) silt loam, very dark brown (10YR 2/2) moist; moderate fine and medium subangular blocky structure; slightly hard, friable; 10 percent by volume of fragments of rock; neutral; clear smooth boundary. (Combined A horizons is 4 to 10 inches thick.)
Bt1--7 to 12 inches; dark grayish brown (10YR 4/2) very cobbly silty clay loam, very dark grayish brown (10YR 3/2) moist; weak medium blocky structure; hard, firm; 50 percent by volume of fragments of rock; neutral; clear smooth boundary.
Bt2--12 to 20 inches; very dark grayish brown (10YR 3/2) extremely cobbly silty clay loam, very dark brown (10YR 2/2) moist; moderate medium blocky structure; very hard, firm; 60 percent by volume of fragments of rock; neutral; abrupt smooth boundary. (Combined Bt horizons is 10 to 16 inches thick.)
Bk--20 to 24 inches; grayish brown (10YR 5/2) extremely cobbly silty clay loam, very dark grayish brown (10YR 3/2) moist; weak coarse subangular blocky structure; slightly hard, friable; 75 percent by volume of fragments of rock; strong effervescence; slightly alkaline; gradual smooth boundary. (2 to 6 inches thick)
C--24 to 60 inches; pale brown (10YR 6/3) extremely cobbly loam, brown (10YR 4/3) moist; massive; slightly hard, friable; 80 percent by volume of fragments of rock; strong effervescence; slightly alkaline.
TYPE LOCATION: Pennington County, South Dakota; about 13 miles west and one mile south of Hill City; 2200 feet north and 2000 feet east of the southwest corner of sec. 36, T. 1 S., R. 2 E.
RANGE IN CHARACTERISTICS: The thickness of the mollic epipedon ranges from 16 to 32 inches. Depth to carbonates ranges from 14 to 26 inches. Coarse fragments are pebbles and cobbles and range from 0 to 15 percent by volume in the surface layer and from 25 to 75 percent by volume in the control section. Depth to consolidated bedrock is greater than 40 inches.
The A horizon has hue of 7.5YR or 10YR, value of 3 or 4 and 2 or 3 moist, and chroma of 1 or 2. It is silt loam or loam. It is slightly acid or neutral.
The Bt horizon has hue of 5YR, 7.5YR, or 10YR; value of 3 to 5 and 2 to 4 moist; and chroma of 2 or 3. It is silty clay loam or clay loam. It averages between 20 and 35 percent clay. It is neutral or slightly alkaline.
The Bk horizon has hue of 5YR, 7.5YR, or 10YR; value of 4 to 6 and 3 to 4 moist; and chroma of 2 to 4. It is silty clay loam or clay loam and it contains from 40 to 75 percent by volume of fragments of rock. It has dissemminated lime or accumulations of carbonate and is slightly or moderately alkaline.
The C horizon has hue of 2.5YR to 10YR, value of 5 to 7 and 4 to 6 moist, and chroma of 2 to 4. It is loam or clay loam and contains 40 to 80 percent by volume of fragments of rock. It is slightly or moderately alkaline.
COMPETING SERIES: These are the Bickmore, Bluebell, Panin, Parkay, Tusel, Woodcock, and Woodhurst series. The Bickmore, Bluebell, Panin, and Woodcock soils have bedrock at a depth of less than 40 inches. Bluebell, Panin, Parkay, Tusel, Woodcock, and Woodhurst do not have accumulations of carbonate below the argillic horizon. In addition, Woodcock soils contain nondispersible sand-size clay aggregates.
GEOGRAPHIC SETTING: Redbird soils are on nearly level to moderately sloping open bottomland parks in mountains at elevations of 6200 to 7200 feet. Slope gradients range from 0 to 10 percent. These soils formed in alluvium from limestone and calcareous sandstone. Mean annual temperature ranges from 37 to 45 degrees F. Mean annual precipitation ranges from 18 to 26 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Heath, Judy, Stovho, and Trebor soils. The Heath and Stovho soils do not have coarse fragments in the solum and are on higher parts of the landscape. The Judy and Trebor soils are moderately deep to bedrock. These soils are on the adjacent uplands. In addition, the Stovho and Trebor soils support a forest.
DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderate and runoff is low to medium.
USE AND VEGETATION: Used mainly for grazing, wildlife, and recreation. Native vegetation is bluegrass, wheatgrass, needlegrass, junegrass, oatgrass, forbs and shrubs.
DISTRIBUTION AND EXTENT: Mountaineous areas of the Black Hills in South Dakota and Wyoming. The Redbird soils are on the Limestone Plateau at higher elevations in the western part of the Black Hills. It is of small 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: mollic epipedon - from the surface to a depth of about 24 inches (A1, A2, Bt1, Bt2 and Bk horizons); argillic horizon - the zone from about 7 to 20 inches (Bt1 and Bt2 horizons).