LOCATION EDWIN SDEstablished Series
TAXONOMIC CLASS: Coarse-silty, mixed, superactive, mesic Entic Haplustolls
TYPICAL PEDON: Edwin silt loam - on a plane slope of less than 1 percent in a cultivated field. When described the soil was dry throughout. (Colors are for dry soil unless otherwise stated.)
Ap--0 to 9 inches; dark grayish brown (2.5Y 4/2) silt loam, very dark grayish brown (2.5Y 3/2) moist; weak medium subangular blocky structure parting to moderate fine granular; soft, very friable; slightly plastic; common fine roots throughout; mildly alkaline; abrupt smooth boundary. (7 to 10 inches thick)
Bk--9 to 27 inches; light yellowish brown (2.5Y 6/4) silt loam, light olive brown (2.5Y 5/4) moist; weak medium and coarse prismatic structure parting to moderate medium and coarse subangular blocky; very hard, friable; slightly plastic; common fine roots throughout; strong effervescence; moderately alkaline; clear wavy boundary. (5 to 27 inches thick)
Cyz1--27 to 37 inches; pale yellow (2.5Y 7/3) silt loam, light olive brown (2.5Y 5/3) moist; massive; hard, friable; few fine roots in cracks; many fine plate like nests of gypsum; common fine threads of salt; slight effervescence; moderately alkaline; clear smooth boundary.
Cyz2--37 to 60 inches; pale yellow (2.5Y 7/3) silt loam varved with very thin layers of very fine sand to clay; light olive brown (2.5Y 5/3) moist; many medium and coarse distinct light gray (2.5Y 7/0) relic mottles; hard, friable; 1 to 2 mm thick varves; few fine plate like nests of gypsum; few fine threads of salt; common fine and medium prominent dark brown (7.5YR 4/4), yellowish brown (10YR 5/6), and brownish yellow (10YR 6/6) iron stains; common fine cylindrical iron concretions; slight effervescence; moderately alkaline.
TYPE LOCATION: Hyde County, South Dakota; about 12 miles north of Highmore; 275 feet south and 1700 feet east of the northwest corner of section 18, T. 114 N., R. 71 W.
RANGE IN CHARACTERISTICS: The thickness of the mollic epipedon ranges from 7 to 10 inches. Depth to free carbonates ranges from 7 to 10 inches but are at or near the surface in some pedons. Depth to varved material is 20 to 40 inches.
The Ap horizon has hue of 10YR or 2.5Y, value of 3 to 5 and 2 or 3 moist, and chroma of 2 or less. It is silt loam or loam with 10 to 18 percent clay. It is neutral to moderately alkaline. Some pedons have an AC horizon.
The Bk horizon has hue of 2.5Y, value of 5 to 7 and 4 to 6 moist, and chroma of 2 to 4. It is silt loam or loam with less than 15 percent fine or coarser sand and less than 18 percent clay. It is mildly alkaline or moderately alkaline.
The Cyz horizon has hue of 2.5Y, value of 6 or 7 and 5 or 6 moist, and chroma of 2 to 4. It is silt loam or loam varved with very thin strata of very fine sand to clay in the lower part. It has few ot many nests of salt and gypsum. It is mildly alkaline to strongly alkaline.
COMPETING SERIES: There are no other soils in this family.
GEOGRAPHIC SETTING: Edwin soils are on glacial lake plains. Slopes are convex and range from 0 to 15 percent. Edwin soils formed on shoulders in calcareous glaciolacustrine sediments of silt sized particles but with varves of very fine sand to clay sized particles. Mean annual air temperature is 45 to 48 degrees F, and mean annual precipitation is 17 to 19 inches. Growing season is about 130 to 150 days; average growing precipitation is 13 to 15 inches; and growing degree days are about 2800 to 3200.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bend, Java, and Tetonka soils. The Bend soils have a cambic horizon and are on back slopes. Java soils are fine-loamy and are on nearby landscapes. The poorly drained Tetonka soils are in basins.
DRAINAGE AND PERMEABILITY: Well drained. Surface runoff is low to high depending on slope. Permeability is slow.
USE AND VEGETATION: Most areas cropped to small grains and alfalfa. Some areas are in native range of sideoats grama, little bluestem, blue grama, big bluestem, needleandthread, western wheatgrass, green needlegrass, sedges, and forbs.
DISTRIBUTION AND EXTENT: East central South Dakota. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Hyde County, South Dakota, 1992.
REMARKS: Diagnostic horizons and features recognized in this pedon are: mollic epipedon - the zone from the surface to a depth of 9 inches (Ap horizon); calcic horizon - the zone of carbonate accumulation from about 9 inches to 27 inches (Bk horizon).