LOCATION CLAMO SD+NEEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Cumulic Vertic Endoaquolls
TYPICAL PEDON: Clamo silty clay loam - on less than 1 percent slope in native grass. When described the soil was moist throughout. (Colors are for moist soil unless otherwise stated.)
A1--0 to 4 inches; black (2.5Y 2/1) silty clay loam, dark gray (2.5Y 4/1) dry; moderate fine granular structure; slightly hard, very friable, slightly sticky; neutral; clear smooth boundary.
A2--4 to 9 inches; very dark gray (5Y 3/1) silty clay loam, dark gray (5Y 4/1) dry; weak coarse prismatic structure parting to weak medium and moderate fine subangular blocky; slightly hard, friable, sticky, and plastic; slightly alkaline; clear smooth boundary. (Combined A horizon thickness is 6 to 14 inches.)
Bg--9 to 15 inches; very dark gray (5Y 3/1) silty clay loam, gray (5Y 5/1) dry; weak medium prismatic structure parting to moderate medium and fine subangular blocky; hard, friable, sticky, and plastic; few fine distinct olive (5Y 5/4) Fe concentrations, moist; slightly alkaline; clear smooth boundary. (4 to 17 inches thick)
Bkg1--15 to 24 inches; very dark grayish brown (2.5Y 3/2) silty clay, grayish brown (2.5Y 5/2) dry; weak medium prismatic structure parting to moderate medium and fine subangular blocky; hard, firm, sticky, and plastic; few fine distinct olive brown (2.5Y 4/4) Fe concentrations; many medium and coarse accumulations of carbonate; strong effervescence; moderately alkaline; clear wavy boundary.
Bkg2--24 to 38 inches; very dark gray (5Y 3/1) silty clay, dark gray (5Y 4/1) dry; weak coarse subangular blocky structure; very hard, firm, sticky, and plastic; many coarse accumulations of carbonate; few fine crystals of gypsum; strong effervescence; moderately alkaline; gradual wavy boundary. (Combined Bkg horizon is 15 to 35 inches thick.)
Cg1--38 to 42 inches; black (5Y 2/1) silty clay, dark gray (5Y 4/1) dry; weak coarse subangular blocky structure; very hard, firm, sticky, and plastic; moderately alkaline; gradual wavy boundary. (0 to l2 inches thick)
Cg2--42 to 60 inches; black (2.5Y 2/1) silty clay, dark gray (2.5Y 4/1) dry; massive; very hard, firm, sticky, and plastic; many medium and coarse nests of gypsum; moderately alkaline.
TYPE LOCATION: Davison County, South Dakota; about 7 miles north and 1 mile east of Mitchell; 2,155 feet south and 100 feet east of the northwest corner of sec. 11, T. 104 N., R. 60 W.
RANGE IN CHARACTERISTICS: The depth to carbonates ranges from 14 to 30 inches. Thickness of the mollic epipedon is 24 to 48 inches. The particle size control section is silty clay loam, silty clay, or clay averaging between 35 and 50 percent clay. Buried horizons are present in some pedons.
The A horizon is neutral or has hue of 10YR, 2.5Y, or 5Y; value of 2 or 3 and 3 or 4 dry; and chroma of 0 or 1. It typically is silty clay loam, silty clay, or clay but is silt loam or loam in some pedons where the upper 6 to 10 inches have been modified by recent deposition. It ranges from moderately acid to slightly alkaline.
The Bg horizon is neutral or has hue of 2.5Y or 5Y, value of 2 or 3 and 3 to 5 dry, and chroma of 0 to 2. It has few or common, faint or distinct redoximorphic features in most pedons. It ranges from slightly acid to slightly alkaline.
The Bk horizon is neutral or has hue of 2.5Y or 5Y, value of 2 to 5 and 4 to 7 dry, and chroma of 1 to 2. It has few or common faint or distinct redoximorphic features. It has common or many accumulations of carbonate and is slightly or moderately alkaline.
The C horizon is neutral or has hue of 2.5Y or 5Y, value of 2 to 5 and 4 to 7 dry, and chroma of 0 to 2. It has few or common, faint or distinct redoximorphic features in some pedons. The C horizon is silty clay loam, silty clay, clay, sandy clay loam, or clay loam but is stratified with thin layers of sand or silt in some pedons. It ranges from neutral to moderately alkaline. Some pedons have sand and gravel at depths below 40 inches.
COMPETING SERIES: These are the Chivato, Lura, Okoboji, Peotone, Shiloh, Woods Cross, Zoe, and Zook soils in the same family. The Chivato soils contain more clay, do not have carbonates, and formed in sediments derived from igneous rock. The Lura soils tend to contain more clay and are in a more moist climate. The Okoboji, Peotone, and Shiloh soils are in areas of higher rainfall. Woods Cross soils receive less rainfall and formed in sediments derived from igneous and metamorphic rocks. Zoe soils receive more rainfall and tend to contain more soluble salts and exchangeable sodium. Zook soils lack free carbonates to depths of 40 inches or more.
GEOGRAPHIC SETTING: The Clamo soils are nearly level on bottom lands and flood plains of the larger tributaries of the Missouri River. Old channels and oxbows dissect these areas. The Clamo soils formed in clayey alluvial sediments. Slopes range from 0 to 2 percent. The mean annual temperatures range from 45 to 52 degrees F, and the mean annual precipitation from 17 to 26 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the Baltic, Bon, Betts, Durrstein, James, Lamo, Luton, and Roxbury soils. Baltic soils are in depressions and contain free carbonates to the surface. Bon and Roxbury soils contain less clay and have loamy control sections and are on slightly higher landscapes than the Clamo soils. Betts soil have a fine-loamy control section and do not have an aquic moisture regime and are on steep adjacent uplands. Durrstein soils have a natric horizon and are on similar landscapes with microrelief. James, Lamo, and Luton soils are on similar landscapes as the Clamo soil. James soils have carbonates at or near the surface and contain more salts. Lamo soils have a fine-silty control section. Luton soils do not have free carbonates to depths of 36 inches or more and do not contain gypsum.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained, poorly drained or very poorly drained; subject to occasional or frequent flooding; water tables range from 2 feet above the surface to 3 feet below the surface. Surface runoff is slow or very slow. Permeability is slow.
USE AND VEGETATION: Principal crops are native hay, pasture, corn, and small grains. Spring farming operations are frequently delayed because of high water tables and flooding. Native grasses are switchgrass, prairie cordgrass, sedges, and Reed canarygrass.
DISTRIBUTION AND EXTENT: Central and eastern South Dakota and northeast Nebraska. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Pierce County, Nebraska, 1970.
REMARKS: Diagnostic horizons and features recognized in this pedon are: mollic epipedon - the zone from the surface of the soil to a depth of about 38 inches (A, A2, Bg, Bkg1, Bkg2 horizon).