LOCATION DELMONT SDEstablished Series
TAXONOMIC CLASS: Fine-loamy over sandy or sandy-skeletal, mixed, superactive, mesic Typic Haplustolls
TYPICAL PEDON: Delmont loam - on 1 percent, north-facing, plane slope in a cultivated field. When described the soil was moist throughout. (Colors are for dry soil unless otherwise stated.)
Ap--0 to 6 inches; dark gray (10YR 4/1) loam, black (l0YR 2/1) moist; weak medium subangular blocky structure parting to weak fine subangular blocky and very fine granular; soft, very friable; slightly alkaline; abrupt wavy boundary. (4 to 10 inches thick)
Bw1--6 to 9 inches; very dark gray (10YR 3/1) loam, black (10YR 2/1) moist; weak coarse prismatic structure parting to weak medium and fine subangular blocky; soft, very friable; few pebbles; slightly alkaline; clear smooth boundary.
Bw2--9 to 15 inches; dark grayish brown (10YR 4/2) loam, very dark grayish brown (10YR 3/2) moist; weak coarse prismatic structure parting to weak coarse and medium subangular blocky; soft, very friable; few pebbles; slightly alkaline; clear wavy boundary. (Combined thickness of the Bw horizons is 6 to 13 inches.)
2C1--15 to 24 inches; grayish brown (10YR 5/2) gravelly sand, dark grayish brown (10YR 4/2) moist; single grained; loose; 25 percent gravel; moderately alkaline; few large accumulations of calcium carbonate; gravel coated with calcium carbonate; strong effervescence; moderately alkaline; gradual wavy boundary.
2C2--24 to 60 inches; light brownish gray (10YR 6/2) gravelly sand, grayish brown (10YR 5/2) moist; single grained; loose; 30 percent gravel; strong effervescence; moderately alkaline.
TYPE LOCATION: Davison County, South Dakota; about 2 1/2 miles east and 3 miles north of Mount Vernon, 320 feet north and 95 feet east of southwest corner, sec. 31, T. 104 N., R. 61 W.
RANGE IN CHARACTERISTICS: The depth to calcium carbonate ranges from 14 to 20 inches, and corresponds to the depth of the underlying sand and gravel, which contains 20 to 45 percent gravel by volume. Thickness of the mollic epipedon ranges from 10 to 20 inches.
The A horizon has value of 3 or 4 and 2 or 3 moist, and chroma of 1 to 3. It typically is loam but is very fine sandy loam or silt loam in some pedons. It ranges from slightly acid to slightly alkaline.
The Bw horizon has value of 3 to 5 and 2 or 3 moist, and chroma of 1 to 3. It typically is loam but is sandy loam, fine sandy loam, sandy clay loam, or clay loam in some pedons. It ranges from slightly acid to slightly alkaline.
A BC or Bk horizon is in some pedons.
The 2C horizon has hue of 5YR to 5Y; value of 5 to 7, 4 to 6 moist; and chroma of 2 to 4. It is gravelly sand, gravelly loamy sand, very gravelly loamy sand, or very gravelly sand and the sand fraction is medium and coarse. Some pedons have horizons that do not have coarse fragments. Some pedons have thin layers of loamy material. It is slightly or moderately alkaline. The gravel typically is crusted and coated with calcium carbonate on the undersides, especially in the upper part.
COMPETING SERIES: These are the Oahe series. Oahe soils have sand and gravel substrata between 20 and 40 inches.
GEOGRAPHIC SETTING: Delmont soils are nearly level to moderately steep on broad outwash plains and terraces. Surfaces are convex and generally short and irregular. Slope gradients range from 0 to 25 percent. The soils formed in loamy alluvium overlying sand and gravel. The mean annual temperature ranges from 45 to 52 degrees F., and mean annual precipitation from 17 to 26 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Blendon, Dempster, Enet, Henkin, and Talmo soils. These soils are on similar landscapes. Blendon and Henkin soils do not have sand and gravel within depths of 40 inches and have a coarse-loamy control section. Dempster and Enet soils have sand and gravel between 20 and 40 inches. Talmo soils have sand and gravel substrata at depths of less than 14 inches.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained. Surface runoff is slow on 0 to 2 percent slopes and medium or rapid on the steeper slopes; permeability is moderately rapid or moderate in the solum and rapid in the underlying sand and gravel.
USE AND VEGETATION: Used for cropland and range. Oats, corn, alfalfa and grain sorghum are the principal crops. Native grasses include little bluestem, sideoats grama, blue grama, needleandthread, and sedges.
DISTRIBUTION AND EXTENT: In east-central and southeastern South Dakota. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Davison 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 15 inches (Ap, Bw1, Bw2 horizon).