LOCATION GRUMMIT SD+MT WYEstablished Series
TAXONOMIC CLASS: Clayey, smectitic, acid, mesic, shallow Aridic Ustorthents
TYPICAL PEDON: Grummit clay - on a convex slope of 5 percent in native grass. When described, the soil was moist to bedded shale. (Colors are for dry soil unless otherwise stated)
A--0 to 3 inches; light brownish gray (10YR 6/2) clay, dark grayish brown (10YR 4/2) moist; moderate fine granular structure; loose, friable; many fine roots; many very fine fragments of shale; very strongly acid; clear smooth boundary. (2 to 6 inches thick)
C1--3 to 7 inches; grayish brown (10YR 5/2) clay, dark grayish brown (10YR 4/2) moist; weak coarse subangular blocky structure; hard, friable; many fine roots; 25 percent very fine fragments of shale; extremely acid; gradual wavy boundary.
C2--7 to 17 inches; grayish brown (10YR 5/2) and gray (2.5Y 5/1) clay, dark grayish brown (10YR 4/2) and dark gray (2.5Y 4/1) moist; common distinct mottles of yellowish brown (l0YR 5/6); weak coarse subangular blocky structure; hard, friable; partially weathered fragments of shale make up 35 percent by volume; common roots; extremely acid; clear smooth boundary.
Cr--17 to 40 inches; gray (10YR 6/1) brittle platy shale, dark gray (10YR 4/1) moist; common medium distinct stains of yellowish brown (10YR 5/8); very hard; extremely acid.
TYPE LOCATION: Butte County, South Dakota; about 4 miles west and 2 miles north of Belle Fourche; 200 feet east and 1800 feet north of the southwest corner of sec. 30, T. 9 N., R. 2 E.
RANGE IN CHARACTERISTICS: Depth to shale ranges from 10 to 20 inches. Colors throughout the soil are inherited from the shale. The horizons overlying the bedded shales typically average 50 to 65 percent clay but ranges from 35 to 65 percent clay. The low clay percentage is due to sand-size shale fragments. Consistence ranges from loose to hard when dry but is friable when moist. The soil ranges from strongly acid to extremely acid.
The A horizon has hue of 10YR or 2.5Y, value of 5 or 6 and 3 or 4 moist, and chroma of 1 or 2 dry or moist. It typically is clay but is clay loam in some pedons. It has weathered fragments of shale that make up 5 to 35 percent by volume. The A horizon contains less than 1 percent more organic matter than the C.
The C horizon has hue of 10YR, 2.5Y, or 5Y; value of 5 or 6 and 3 or 4 moist; and chroma of 1 or 2. Weathered fragments of shale make up 20 to over 50 percent by volume of the C horizon.
The fissile shale is very hard and brittle and will not disperse in water or in sodium hexametaphosphate.
COMPETING SERIES: There are no other soils in the same family. Other competing soils are the Dupree, Lismas, and Samsil series. Dupree soils are more moist and have firm to extremely firm consistence. Lismas soils are more alkaline and have a firmer consistence. Samsil soils contain carbonates and are alkaline.
GEOGRAPHIC SETTING: Grummit soils are gently sloping to very steep on uplands. Slope gradients range from 2 to 60 percent. The soil formed in clayey residuum weathered from acid shales. Mean annual temperature ranges from 43 to 50 degrees F, and mean annual precipitation is about 12 to 18 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Broadhurst, Graner, and Demar soils. All of these associated soils are deeper to bedded shale. The Broadhurst and Demar soils are on adjacent, nearly level to gently sloping fans and terraces. In addition, Demar soils have argillic horizons. Graner soils are on nearby undulating to rolling uplands. Grummit soils are also associated with rock outcrop.
DRAINAGE AND PERMEABILITY: Well drained. Runoff is slow or medium. Permeability is moderate or moderately slow in the upper part and moderate in the underlying material.
USE AND VEGETATION: These soils are used primarily as native rangeland. Native vegetation typically is little bluestem, western wheatgrass, green needlegrass, blue grama, sideoats grama, and needleandthread. Short, limby, ponderosa pine is on some places.
DISTRIBUTION AND EXTENT: Western South Dakota and eastern Wyoming. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Butte County, South Dakota, 1970.
REMARKS: Diagnostic horizons and features recognized in this pedon are: ochric epipedon - the zone from the surface of the soil to a depth of 3 inches (A horizon).