LOCATION JAMES SDEstablished Series
TAXONOMIC CLASS: Fine, smectitic, calcareous, mesic Cumulic Vertic Endoaquolls
TYPICAL PEDON: James silty clay - on a slope of less than 1 percent in native grass. When described the soil was moist to 2 inches, dry from 2 to 20 inches and moist from 20 to 60 inches. (Colors are for moist soil unless otherwise stated.)
Az1--0 to 1 inch; black (N 2/0) silty clay, very dark gray (N 3/0) dry; weak fine granular structure; slightly hard, firm, sticky and plastic; common fine accumulations of salts; slight effervescence; slightly alkaline; clear smooth boundary.
Az2--1 to 10 inches; black (N 2/0) silty clay, very dark gray (N 3/0) dry; weak medium subangular blocky structure parting to weak fine subangular blocky; very hard, firm, sticky, and plastic; many fine and medium threads of salts; strong effervescence; moderately alkaline; clear smooth boundary. (Combined thickness of the A horizon is 8 to 20 inches.)
Bz--10 to 20 inches; black (N 2/0) silty clay, dark gray (N 3/0) dry; weak medium and coarse subangular blocky structure parting to moderate very fine and fine subangular blocky; very hard, very firm, sticky, and plastic; many fine threads of salts; strong effervescence; strongly alkaline; clear wavy boundary. (6 to 40 inches thick)
Azb--20 to 40 inches; black (N 2/0) silty clay, dark gray (N 4/0) dry; weak coarse subangular blocky structure parting to weak very fine and fine subangular blocky; very hard, very firm, sticky, and plastic; common fine and medium accumulations of gypsum and other salts; slight effervescence; moderately alkaline; gradual wavy boundary. (0 to 30 inches thick)
Akyb--40 to 54 inches; black (N 2/0) silty clay, dark gray (N 4/0) dry; massive; very hard, very firm, sticky, and plastic; few fine faint very dark grayish brown (2.5Y 3/2) Fe concentrations; many coarse accumulations of gypsum; few medium accumulations of carbonate; strong effervescence; moderately alkaline; gradual wavy boundary. (0 to 30 inches thick)
Cky--54 to 60 inches; very dark grayish brown (2.5Y 3/2) silty clay, dark grayish brown (2.5Y 4/2) dry; massive; very hard, very firm, sticky and plastic; few fine faint dark grayish brown (2.5Y 4/2) Fe concentrations; many coarse accumulations of gypsum; many coarse accumulations of carbonate; strong effervescence; moderately alkaline.
TYPE LOCATION: Hanson County, South Dakota; about 7 miles south and 2 miles west of Alexandria; 1100 feet west and 620 feet north of the southeast corner of sec. 18, T. 101 N., R. 58 W.
RANGE IN CHARACTERISTICS: Thickness of mollic epipedon ranges from 24 to over 60 inches. Redoximorphic features in many pedons are masked by the dark matrix colors. Free carbonate is at or within 10 inches of the surface. The particle size control section is silty clay loam, silty clay, or clay averaging between 35 and 60 percent clay, but some layers will exceed 60 percent clay. Buried horizons are common below depths of 20 inches but are at depths of less than 20 inches in some pedons. The electrical conductivity ranges from about 8 to 20 or more mmhos/cm in the upper part of the pedon. Visible accumulations of salts range from few to many and fine to medium in the solum.
The A horizon has hue of 10YR, 2.5Y, 5Y or is neutral, value of 2 or 3 and 3 or 4 dry, and chroma of 1 or less. It is silty clay loam, silty clay, or clay. It is slightly alkaline to strongly alkaline.
The Bz horizon has hue of 2.5Y or 5Y, or is neutral, value of 2 or 3 and 2 to 4 dry, and chroma of 2 or less. Some pedons have faint or distinct redoximorphic features. It is slightly alkaline to strongly alkaline. Some pedons have Bzy, Bkg, or BC horizons.
The Ab horizon has hue of 2.5Y or 5Y or neutral, value of 2 or 3 and 2 to 5 dry, and chroma of 2 or less. It typically is silty clay loam, silty clay, or clay, but some pedons have thin strata of coarser materials below depths of 40 inches. It is slightly alkaline to strongly alkaline. Some buried layers do not have carbonates.
The C horizon has hue of 2.5Y or 5Y or is neutral, value of 2 to 5 and 4 to 6 dry and chroma of 1 or 2. It is clay, silty clay or silty clay loam, but some pedons have thin layers of silty and loamy materials. It is slightly alkaline to strongly alkaline.
COMPETING SERIES: These are the Baltic, Holly Springs, Knoke, and Nishna series in the same family. The Baltic, Holly Springs, Knoke, and Nishna soils do not have salts in the solum. In addition, Baltic and Nishna soils typically do not have buried horizons. Holly Springs and Nishna soils typically do not have gypsum crystals within the series control section and Holly Springs soils contain less clay in the upper part of solum.
GEOGRAPHIC SETTING: The James soils are nearly level on plane to slightly concave floodplains. They are mainly on low flats that entrap water, at the base of foot slopes some distance from the present stream channel or in abandoned stream channels. Slope gradients are less than 1 percent. They formed in clayey alluvium. The mean annual temperature ranges from 45 to 52 degrees F, and the mean annual precipitation ranges from 18 to 26 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Clamo, Lamo, Salmo, and Wann soils. The Clamo and Lamo soils are on slightly higher areas. Clamo soils do not have carbonate in the upper part of the solum and contain less salts. Lamo soils are fine-silty and contain less salts. Salmo soils are fine-silty and are on similar landscapes. Wann soils are coarse-loamy and are on higher parts of the floodplain.
DRAINAGE AND PERMEABILITY: Poorly drained or very poorly drained. Surface runoff is very slow or ponded. Permeability is slow or very slow. The soils are subject to occasional or frequent flooding from stream overflow. A water table is near the surface during the spring and at depths of 4 to 5 feet in the fall.
USE AND VEGETATION: Used mainly for hay and pasture. Native grasses include prairie cordgrass, inland saltgrass, switchgrass, and western wheatgrass.
DISTRIBUTION AND EXTENT: Southeastern South Dakota. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Union County, South Dakota, 12/17/74.
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 54 inches. (Az1, Az2, Bz, Azb, Akyb horizons)