LOCATION MACKEN SDEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Vertic Epiaquolls
TYPICAL PEDON: Macken silty clay loam in a flat closed basin in native grass. When described the soil was moist throughout. (Colors are for moist soil unless otherwise stated)
A--0 to 2 inches; very dark gray (10YR 3/1) silty clay loam, gray (10YR 5/1) dry; weak fine subangular blocky and moderate fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; few fine and very fine concretions (Fe & Mn oxides); neutral; clear smooth boundary. (2 to 4 inches thick)
Bw--2 to 8 inches; very dark gray (10YR 3/1) silty clay, dark gray (10YR 4/1) dry; weak medium prismatic structure parting to moderate medium and fine subangular blocky; hard, firm, sticky and plastic; few fine and very fine concretions (Fe & Mn oxides); neutral; gradual wavy boundary.
Bg--8 to 26 inches; very dark gray (5Y 3/1) silty clay, dark gray (5Y 4/1) dry; moderate medium and coarse prismatic structure parting to strong medium and fine blocky; very hard, firm, sticky and plastic; few fine and very fine concretions (Fe & Mn oxides); slightly alkaline; gradual smooth boundary. (Combined Bw and Bg horizons 10 to 46 inches thick)
Bkg1--26 to 39 inches; olive gray (5Y 4/2) silty clay, gray (5Y 5/1) dry; few fine distinct strong brown (7.5YR 5/8) redox concentrations; weak medium and fine subangular blocky structure; very hard, firm, sticky and plastic; few fine accumulations and striations of carbonate; strong effervescence; moderately alkaline; clear smooth boundary.
Bkg2--39 to 60 inches; light olive gray (5Y 6/2) silty clay loam, light gray (5Y 7/2) dry; massive; hard, friable, slightly sticky and slightly plastic; common medium and fine accumulations of carbonate; violent effervescence; moderately alkaline.
TYPE LOCATION: Sully County, South Dakota; about 7 miles south and 8 miles west of Onida; 1,260 feet west and 245 feet south of the northeast corner of Sec. 17, T. 113 N., R. 78 W.
RANGE IN CHARACTERISTICS: The depth to carbonate ranges from 12 to 40 inches. The thickness of the mollic epipedon ranges from 22 to 34 inches. The control section averages between 45 to 60 percent clay. When the soil is dry, cracks 1/2 to 2 inches wide and several feet long extend downward through the solum.
The A horizon has hue of 10YR or 2.5Y, value of 2 or 3 and 4 or 5 dry. It typically is silty clay loam but is silty clay or clay in some pedons. It is slightly acid or neutral.
The Bw and Bg horizons have hue of 10YR, 2.5Y, 5Y, or is neutral, value of 2 or 3 and 4 or 5 dry, and chroma of 0 or 1. It has weak or moderate, medium or coarse prismatic structure that parts to moderate or strong, fine or medium angular or subangular blocky. It is silty clay or clay and ranges from neutral to moderately alkaline.
The Bkg horizon has hue of 2.5Y or 5Y, value of 4 to 6 and 5 or 7 dry, and chroma of 1 to 3. It is silty clay, silty clay loam or clay. It is slightly alkaline or moderately alkaline. Most pedons contain few or common, fine or medium accumulations of carbonates. Buried horizons are below depths of 36 inches in some pedons. Some pedons have C horizons.
COMPETING SERIES: These are the Cosmos, Cove, Marna and Waldorf soils. Cosmos soils have 2Bk horizons of glacial till containing up to 5 percent rock fragments within depths of 40 inches. In addition, they formed in areas having mean annual precipitation of more than 26 inches. Cove soils do not have carbonates within a depth of 60 inches. Marna soils have a loam or clay loam glacial till 2Bk horizon within depths of 40 inches. Waldorf soils formed in areas having mean annual precipitation of more than 25 inches.
GEOGRAPHIC SETTING: Macken soils are in basins in the uplands. Micro relief is pronounced in some areas. Slopes are 0 to 1 percent. The soils formed in local clayey alluvium. Mean annual air temperature ranges from 45 to 48 degrees F., and mean annual precipitation ranges from 12 to 21 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Glenham, Highmore, Hoven, Raber and Onita soils. Glenham, Highmore and Raber are well drained on higher parts of the landscape. Hoven soils have natric horizons and are in similar landscapes. Onita soils are moderately well drained and are on footslopes.
DRAINAGE AND PERMEABILITY: Poorly or very poorly drained. Negligible surface runoff unless artificially drained. Macken soils are ponded from surface runoff from surrounding soils for 30 days or more in most years. Permeability is slow except after extended dry periods the initial intake is rapid due to cracks.
USE AND VEGETATION: Mostly native range and hayland. Western wheatgrass is the principal native species with some sedges and forbs in the wetter areas.
DISTRIBUTION AND EXTENT: Central South Dakota. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Hughes County, South Dakota, 12/70.
REMARKS: Diagnostic horizons and features recognized in this pedon are: mollic epipedon - the zone from the surface of the soil to a depth of 26 inches (A, Bw and Bg).