LOCATION DEMKY SDEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Glossic Natrustolls
TYPICAL PEDON: Demky loam - in a native grass on a plane slope of 2 percent. When described the soil was dry throughout. (Colors are for dry soil unless otherwise stated.)
A1--0 to 3 inches; dark gray (10YR 4/1) crushing to dark grayish brown (10YR 4/2) loam, very dark grayish brown (10YR 3/2) moist; weak thin platy structure; soft, friable; neutral; clear smooth boundary.
A2--3 to 6 inches; dark gray (10YR 4/1) loam, very dark grayish brown (10YR 3/2) moist; weak medium subangular blocky structure; soft, friable; neutral; clear smooth boundary. (Combined A horizons is 5 to 9 inches thick.)
B/E--6 to 8 inches; grayish brown (10YR 5/2) clay loam (B), very dark grayish brown (10YR 3/2) moist; thin nearly continuous coatings of gray (10YR 6/1) silt and very fine sand (E) on faces of peds; weak medium prismatic structure parting to moderate medium subangular blocky; slightly hard, friable; slightly sticky and slightly plastic; neutral; clear smooth boundary. (2 to 3 inches thick)
Btn--8 to 14 inches; grayish brown (2.5Y 5/2) clay loam, dark grayish brown (2.5Y 4/2) moist; moderate medium prismatic structure parting to strong medium blocky; very hard, firm, sticky and plastic; very dark grayish brown (10YR 3/2) coatings on vertical faces of peds; shiny coats on faces of peds; slightly alkaline; clear wavy boundary. (5 to 12 inches thick)
Bk1--14 to 22 inches; light brownish gray (2.5Y 6/2) clay loam, dark grayish brown (2.5Y 4/2) moist; weak coarse prismatic structure parting to moderate medium subangular blocky; hard, firm, sticky and plastic; common medium and coarse accumulations of carbonate; strong effervescence; moderately alkaline; gradual wavy boundary.
Bk2--22 to 36 inches; light brownish gray (2.5Y 6/2) clay loam, dark grayish brown (2.5Y 4/2) moist; weak coarse subangular blocky structure; hard, firm, sticky and plastic; common medium and fine accumulations of carbonate; strong effervescence; moderately alkaline; gradual wavy boundary. (Combined Bk horizons 13 to 28 inches thick.)
Cy--36 to 60 inches; light brownish gray (2.5Y 6/2) clay loam, grayish brown (2.5Y 5/2) moist; common fine mottles of light gray (2.5Y 7/1) and olive yellow (2.5Y 6/6) moist; hard, firm, sticky and plastic; few fine yellowish red (5YR 5/8) iron accumulations; few fine nests of gypsum; strong effervescence; moderately alkaline.
TYPE LOCATION: Sully County, South Dakota; about 3 miles south and 6 1/2 miles east of Onida; 1834 feet north and 488 feet west of the southeast corner of sec. 27, T. 114 N., R. 76 W.
RANGE IN CHARACTERISTICS: The depth to carbonates typically is about 14 inches but ranges from 12 to 22 inches. The thickness of mollic epipedon ranges from 7 to 16 inches and in some pedons extends into the Bt horizon. The natric horizon contains an estimates SAR or ESP of 10 to 20.
The A horizon has hue of 10YR, value of 4 or 5 and 2 or 3 moist, and chroma of 1 or 2. It is silt loam or loam and is slightly acid or neutral. Some pedons have thin E horizons which have hue of 10YR, value of 6 or 7, and chroma of 1 or 2 dry or moist.
The B/E horizon has colors of the E and Bt horizons. It typically is clay loam, but some pedons are silty clay loam or silt loam. It is slightly acid or neutral.
The Bt horizon has hue of 10YR, value of 4 or 5 and 3 or 4 moist, and chroma of 2 or 3. It is clay loam or clay averaging between 35 and 45 percent clay and more than 15 percent fine sand or coarser. It is slightly alkaline or moderately alkaline.
The Bk horizon has hue of 10YR or 2.5Y, value of 5 to 7 and 4 or 5 moist, and chroma of 2 to 4. It is clay loam or clay. It has few to many, fine or medium accumulations of carbonate. It is moderately alkaline or strongly alkaline. Some pedons have a Btk or Bkz horizons.
The C horizon has hue of 10YR or 2.5Y hue, value of 5 to 7 and 4 or 5 moist, and chroma of 2 to 4. It is loam or clay loam. Accumulations of gypsum and other salts are in most pedons. It is slightly alkaline or moderately alkaline.
COMPETING SERIES: These are the Stickney and Walke soils. Stickney soils have thicker mollic epipedons. Walke soils contain more silt and less sand in the solum.
GEOGRAPHIC SETTING: Demky soils typically are nearly level on uplands. Slope gradients range from 0 to 6 percent. Slopes are plane to concave. These soils formed in glacial till. The mean annual temperature ranges from 45 to 49 degrees F, and the mean annual precipitation ranges from 15 to 20 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cavo, Glenham, Jerauld, Oko, and Raber soils. The Cavo and Jerauld soils are on slightly lower flats and in lows of the microrelief. Cavo soils lack B/E horizons. The Jerauld soils have salts within 16 inches of the surface and do not have a B/E horizon. Glenham, Oko, and Raber soils do not have a natric horizon and are on the plane or convex slopes.
DRAINAGE AND PERMEABILITY: Moderately well drained. Runoff is medium or high. Permeability is slow.
USE AND VEGETATION: Both native grass and cultivated crops. The main crops are winter wheat, corn, oats, and alfalfa. Native vegetation mainly is western wheatgrass, green needlegrass, little bluestem, sideoats grama, blue grama, sedges, and forbs.
DISTRIBUTION AND EXTENT: Central and south-central South Dakota east of the Missouri River. It is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Hughes County, South Dakota, 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 8 inches (A, A2 & B/E horizons); Natric horizon - the zone from about 8 to 14 inches (Btn horizon).