LOCATION STOVHO SD+WYEstablished Series
TAXONOMIC CLASS: Fine, smectitic Inceptic Haplocryalfs
TYPICAL PEDON: Stovho silt loam - on nearly level slope of 1 percent under ponderosa pine forest at an elevation of 6840 feet. When described, the soil was moist throughout. (Colors are for dry soil unless otherwise stated.)
Oi--1 to 0 inch; slightly decomposed forest litter. (0 to 2 inches thick)
A--0 to 2 inches; dark gray (10YR 4/1) silt loam, black (10YR 2/1) moist; weak medium platy structure; soft, very friable; moderately acid; clear smooth boundary. (0 to 4 inches thick)
E--2 to 6 inches; light gray (10YR 7/2) silt loam, grayish brown (10YR 5/2) moist; weak fine and medium platy structure; soft, very friable; moderately acid; clear wavy boundary. (2 to 8 inches thick)
B/E--6 to 8 inches; pale brown (10YR 6/3) silty clay loam, brown (10YR 4/3) moist (Bt); light gray (10YR 7/2) silt loam, grayish brown (10YR 5/2) moist (E); weak medium prismatic structure parting to moderate fine and medium blocky; slightly hard, friable; slightly acid; abrupt wavy boundary. (0 to 15 inches thick)
Bt--8 to 17 inches; yellowish brown (10YR 5/4) silty clay, dark yellowish brown (10YR 4/4) moist; weak medium prismatic structure parting to strong medium blocky; hard, firm; slightly acid; clear wavy boundary. (8 to 25 inches thick)
Bk--17 to 30 inches; light yellowish brown (10YR 6/4) silty clay loam, yellowish brown (10YR 5/4) moist; weak coarse prismatic structure; hard, firm; 10 percent fragments of rock; strong effervescence; few fine accumulations of carbonate; slightly alkaline; gradual wavy boundary. (4 to 20 inches thick)
C--30 to 60 inches; yellow (10YR 7/6) channery silty clay loam, yellowish brown (10YR 5/6) moist; massive; slightly hard, friable; 25 percent fragments of rock; violent effervescence; moderately alkaline.
TYPE LOCATION: Pennington County, South Dakota; about 4 miles south and 12 miles west of Hill City; 1500 feet east and 2000 feet north of the southwest corner of sec. 18, T. 2 S., R. 3 E.
RANGE IN CHARACTERISTICS: Depth to carbonates ranges from 14 to 40 inches. Content of fragments of rock ranges from 0 to 25 percent by volume in the solum and 5 to 50 percent in the C horizon. Depth to consolidated bedrock typically is below 60 inches but ranges from 40 to 60 inches in some pedons.
The A horizon has hue of 10YR, value of 4 or 5 and 2 or 3 moist, and chroma of 1 or 2. It is silt loam or loam. It is moderately acid or slightly acid.
Some pedons have a O horizon up to 3 inches thick.
The E horizon has hue of 10YR or 7.5YR, value of 5 to 7 and 4 or 5 moist, and chroma of 2 or 3. It is silt loam, loam, or very fine sandy loam. It is moderately acid or slightly acid.
The B & E horizon has color of the E and Bt horizons.
The Bt horizon has hue of 10YR or 7.5YR, value of 5 to 7 and 4 or 5 moist, and chroma of 2 to 4. It is silty clay, silty clay loam, or clay and contains up to 25 percent cobbles and channers. It ranges from 35 to 60 percent clay with less than 15 percent fine sand or coarser. It ranges from moderately acid to neutral.
The Bk horizon has hue of 10YR or 7.5YR, value of 4 to 7 and 4 to 6 moist, and chroma of 2 to 4. It is silty clay loam or clay loam and contains up to 25 percent cobbles and channers. It has few to common accumulation of carbonate. It ranges from neutral to moderately alkaline.
Some pedons have a BC horizon. It is neutral to moderately alkaline.
The C horizon has hue of 2.5Y to 7.5YR, value of 6 to 8 and 5 to 7 moist, and chroma of 2 to 6. It is silty clay loam, clay loam or silt loam and contains up to 50 percent cobbles, channers, and flagstones. It is slightly alkaline or moderately alkaline.
COMPETING SERIES: These are the Bead, Chubbs, Cowdrey, Dell, Foxton, Gateway, Lail, McVickers, Mikesell, Muggins, Nokhum, Owlcan, and Wetterhorn series. Gateway soils have a paralithic contacts at depths less than 40 inches. Bead soils formed in noncalcareous bedrock, typically have redder hue and typically are more acid throughout. Chubbs, Foxton, and Wetterhorn soils have a lithic contact at depths less than 40 inches. Cowdrey and Dell soils have more fine sand or coarser. In addition, Cowdrey soils formed in glacial till. Lail soils have redder hue. McVickers, Mikesell, and Muggins do not have carbonates and contain more fine sand or coarser. In addition, McVickers soils formed residuum of extremely hard sandstone; Mikesell soils typically contain more coarse fragments in the solum; and Muggins soils have redder hue. Nokhum soils contain more fine sand or coarser. Owlcan soils contain more fine sand or coarser, do not have a B/E horizon and formed in alluvium.
GEOGRAPHIC SETTING: Stovho soils are nearly level to very steep on mountains at elevations of 6200 to 7200 feet. Slope gradients range from 0 to 50 percent. These soils formed in residuum weathered from limestone and calcareous sandstone. Mean annual temperature ranges from 37 to 45 degrees F, and mean annual precipitation ranges from 18 to 26 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Heath, Judy, Lail, Redbird, and Trebor soils. The Heath, Judy, and Redbird soils have a mollic epipedon and they are on adjacent open parks. The Lail soils have a redder hue and the Trebor soils are moderately deep to bedrock. These soils are on similar positions as the Stovho soil.
DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderately slow or slow. Runoff is low to very high.
USE AND VEGETATION: Used primarily for timber production, woodland grazing, wildlife habitat, and recreation. The dominant overstory is ponderosa pine with smaller amounts of spruce, aspen and birch. The dominant understory is sedges, bearded wheatgrass, oatgrass, bromegrass, common juniper, Oregon grape, arrowleaf balsamroot, bearberry, and iris.
DISTRIBUTION AND EXTENT: High elevations of the Black Hills in western South Dakota and eastern Wyoming. The series is of moderate extent.
MLRA OFFICE RESPONSIBLE: Bismarck, North Dakota
SERIES ESTABLISHED: Lawrence County, South Dakota, 1977.
REMARKS: Classification is being changed from a Mollic to a Typic Cryoboralf to better represent the soils of the Black Hills since a large acreage has been added in Custer-Pennington Counties, South Dakota. The type location is changed to Pennington County, South Dakota.
Diagnostic horizons and features recognized in this pedon are: ochric epipedon - the zone from the surface of the soil to a depth of about 6 inches (A, E horizons); argillic horizon - the zone from about 6 to 17 inches (B/E, Bt horizons).
ADDITIONAL DATA: NSSL data 76PO698-705.