LOCATION PIERRE SD+MT NEEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Aridic Leptic Haplusterts
TYPICAL PEDON: Pierre clay - on a convex slope of 7 percent in native grass. (Colors are for dry soil unless otherwise stated)
A--0 to 2 inches; grayish brown (2.5Y 5/2) clay, dark grayish brown (2.5Y 4/2) moist; moderate fine subangular blocky structure parting to weak very fine granular; hard, firm, sticky and plastic; 1 percent pebbles; slight effervescence; moderately alkaline; clear smooth boundary. (2 to 7 inches thick)
ABss--2 to 7 inches; light brownish gray (2.5Y 6/2) clay, dark grayish brown (2.5Y 4/2) moist; weak medium blocky structure; very hard, very firm, very sticky and very plastic; common distinct non-intersecting slickensides; 1 percent pebbles; strong effervescence; moderately alkaline; clear wavy boundary. (0 to 6 inches thick)
Bss--7 to 20 inches; light brownish gray (2.5Y 6/2) clay, dark grayish brown (2.5Y 5/2) moist; moderate medium and coarse prismatic structure; extremely hard, very firm, very sticky and very plastic; common distinct intersecting slickensides; few fine accumulations of iron; 1 percent pebbles; strong effervescence; moderately alkaline; gradual wavy boundary.
Bssy--20 to 27 inches; light brownish gray (2.5Y 6/2) clay, dark grayish brown (2.5Y 4/2) moist; moderate coarse prismatic structure; extremely hard, very firm, very sticky and very plastic; common distinct intersecting slickensides; few fine nests of iron and common fine accumulations of gypsum; 1 percent pebbles; strong effervescence; moderately alkaline; gradual wavy boundary. (Combined Bss horizons 5 to 20 inches thick)
Cr1--27 to 40 inches; light brownish gray (2.5Y 6/2) soft shale bedrock, dark grayish brown (2.5Y 4/2) moist; common distinct strong brown (7.5YR 5/6) and yellowish brown (10YR 5/6) iron stains; many fine accumulations of gypsum and carbonate; 1 percent pebbles; strong effervescence; slightly alkaline; gradual wavy boundary.
Cr2--40 to 60 inches; light olive gray (5Y 6/2) soft shale bedrock, olive dark gray (5Y 4/1) moist; common distinct strong brown (7.5YR 5/6) iron stains; 1 percent pebbles; slightly alkaline.
TYPE LOCATION: Haakon County, South Dakota; about 9 miles north and 1 mile east of Philip; 560 feet north and 1300 feet east of the southwest corner of sec. 30, T. 3 N., R. 21 E.
RANGE IN CHARACTERISTICS: The soil contains carbonates at or within 6 inches of the surface. The depth to soft shale bedrock ranges from 20 to 40 inches but commonly is at depths of 25 to 35 inches. The horizon above the shale has 0 to 60 percent, by volume soft shale fragments. The control section is 50 to 60 percent clay. When the soil is dry, cracks 1/2 inch to 2 inches wide and several feet long extend downward through the solum. The soil does not have a mollic epipedon, but the upper 10 inches of the solum has an average organic carbon content between 0.6 and 1.7 percent. The soil has a SAR of 1 to 7.
The A horizon has hue of 10YR to 5Y, value of 4 to 6 and 3 to 5 moist, and chroma of 1 to 3. It typically is clay but is silty clay in some pedons. It ranges from slightly acid to moderately alkaline. When the soil is dry it has a light gray (2.5Y 7/2) smooth, porous, platy surface crust ranging from 1/4 to 1 inch in thickness. Where the horizon has mollic colors, it is too thin to be a mollic epipedon. Some pedons do not have an AB horizon.
The Bss horizons have hue of 2.5Y or 5Y, value of 5 or 6 and 4 or 5 moist, and chroma of 1 to 3. They are extremely hard or very hard when dry and extremely firm to firm when moist. They range from neutral to moderately alkaline.
Bk and C horizons are present in some pedons.
The Cr horizon is soft shale bedrock and ranges from slightly acid to moderately alkaline. Bedding planes are evident in the partially weathered shale in some pedons. Gypsum and other salts are concentrated in very thin seams within the shale in some pedons.
COMPETING SERIES: There are no competing series in the same family.
GEOGRAPHIC SETTING: Pierre soils are on nearly level to steep uplands. Slope gradient typically is 3 to 15 percent, but ranges from 0 to 30 percent. The soils formed in residuum weathered from clay shale. Gilgai microrelief is in most areas. Mean annual air temperature is 44 to 53 degrees F, and mean annual precipitation ranges from 12 to 16 inches. Growing season is 125 to 140 days; average growing season precipitation is 10 to 13 inches; and growing degree days are 2600 to 3100. Elevation is 1300 to 3600 feet.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Hisle, Kyle, Lismas, Samsil and Swanboy soils. Hisle soils are in micro-lows and have a natric horizon. Kyle and Swanboy soils have more than 60 percent clay in the series control section; do not have shale bedrock within a depth of 40 inches; and are on the footslopes, toeslopes, and fans below the Pierre soils. Lismas and Samsil soils are on steeper landscapes and have shale bedrock within a depth of 20 inches.
DRAINAGE AND PERMEABILITY: Well drained. Runoff is low on nearly level areas and medium to very high on the more sloping areas. Permeability is very slow, except after dry periods when the initial intake may be rapid due to cracks.
USE AND VEGETATION: Used primarily as rangeland. Native grasses are mainly western wheatgrass, green needlegrass, sideoats grama, blue grama, buffalograss, and forbs.
DISTRIBUTION AND EXTENT: Western South Dakota and northwest Nebraska. This series is of large extent.
MLRA OFFICE RESPONSIBLE: Bismarck, North Dakota
SERIES ESTABLISHED: Belle Fourche Area, South Dakota, 1907.
REMARKS: Diagnostic horizons and features recognized in this pedon are: ochric epipedon - the zone from the surface of the soil to a depth of 7 inches (A and ABss horizons); cambic horizon - the zone from 7 to 27 inches (Bss and Bssy horizons).
ADDITIONAL DATA: NSSL data 85PO015-85PO021 and 85PO022-85PO027.