LOCATION SAWDUST SDEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, calcareous, frigid Typic Ustorthents
TYPICAL PEDON: Sawdust channery loam - on a south-facing slope of 34 percent under sparse pine and native grass at 5460 feet elevation. When described, the soil was dry throughout. (Colors are for dry soil unless otherwise noted).
A--0 to 4 inches; dark grayish brown (10YR 4/2) channery loam, very dark brown (10YR 2/2) moist; weak fine granular structure; soft, very friable; 30 percent coarse fragments; strong effervescence; slightly alkaline; gradual wavy boundary. (2 to 10 inches thick)
AC--4 to 8 inches; pale brown (10YR 6/3) very channery loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; soft, friable; 50 percent coarse fragments; strong effervescence; moderately alkaline; gradual wavy boundary. (0 to 8 inches thick)
C1--8 to 15 inches; light yellowish brown (10YR 6/4) very channery loam, dark yellowish brown (10YR 4/4) moist; massive; soft, friable; 60 percent coarse fragments; many partially weathered limestone pebbles; strong effervescence; moderately alkaline; gradual wavy boundary.
C2--15 to 26 inches; very pale brown (10YR 7/4) extremely channery loam, light yellowish brown (10YR 6/4) moist; massive; soft, friable; 70 percent coarse fragments; strong effervescence; moderately alkaline; gradual wavy boundary.
C3--26 to 60 inches; yellow (10YR 7/6) extremely channery sandy loam, brownish yellow (10YR 6/6) moist; massive; soft, friable; 85 percent coarse fragments; strong effervescence; moderately alkaline.
TYPE LOCATION: Custer County, South Dakota; about 9 miles west and 5 miles south of Custer; 2600 feet north and 1900 feet east of southwest corner sec. 20, T. 4 S., R. 3 E.
RANGE IN CHARACTERISTICS: The Sawdust soils typically have carbonates to the surface but some pedons are leached to a depth of 4 inches. The depth to bedrock is more than 40 inches. Rock fragments which are dominantly pebbles and channers range from 5 to 45 percent by volume in the upper 10 inches. They range from 35 to 90 percent by volume in the control section and are dominantly channers and flagstones. Some pedons have a thin O horizon.
The A horizon has 7.5YR or 10YR hue, value of 3 to 6 dry and 2 to 4 moist, and chroma of 1 to 3. It typically is gravelly loam, gravelly silt loam or channery loam, but is loam or silt loam, channery silt loam, very channery loam, very gravelly loam or very gravelly silt loam in some pedons. It is neutral or slightly alkaline. When the A horizon is thicker than 6 inches, the lower part has value of 5 or 6 dry and 4 moist.
The AC horizon has 5 YR, 7.5YR, or 10YR hue; value of 5 to 7 dry and 4 or 5 moist; and chroma of 2 to 5. It is loam or silt loam and contains up to 50 percent coarse fragments of rock. It is slightly or moderately alkaline.
The C horizon has 2.5YR through 10YR hue, value of 5 to 8 dry and 4 to 7 moist, and chroma of 3 to 6. It is sandy loam, silt loam, silty clay loam, loam or clay loam and contains 35 to 90 percent coarse fragments. It is slightly or moderately alkaline.
COMPETING SERIES: These are the Pathead series that have bedrock at depths of 20 to 40 inches.
GEOGRAPHIC SETTING: The Sawdust soils are on moderately sloping to very steep mountain side slopes at elevations of 3600 to 6200 feet. Slope gradients range from 6 to 80 percent. These soils formed in colluvial or residuum weathered from calcareous limestone or 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 Gurney, Hopdraw, Paunsaugunt and Vanocker soils. The Gurney soils have bedrock at depths between 20 and 40 inches and have an argillic horizon and are in open areas. The Hopdraw soils contain more sand and are on similar landscapes. The Paunsaugunt soils are shallow to bedrock and are on higher convex areas in the landscape. The Vanocker soils have an argillic horizon and are on similar landscapes with a more dense cover of trees.
DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderate. Runoff is medium or high.
USE AND VEGETATION: Used mainly for grazing, timber production, wildlife and recreation. Native vegetation is sparse stand of ponderosa pine with an understory of little bluestem, big bluestem, needlegrass, sideoats grama, junegrass, western wheatgrass, stiff sunflower, prairie clover, juniper, snowberry, rose and sedges.
DISTRIBUTION AND EXTENT: Mountainous areas of the Black Hills in South Dakota and Wyoming especially on the sedimentary formations. The series is of moderate extent.
MLRA OFFICE RESPONSIBLE: Bismarck, North Dakota
SERIES ESTABLISHED: Custer County, South Dakota, 1985.