LOCATION ORTON SDEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Typic Haplustolls
TYPICAL PEDON: Orton loam - on a northeast-facing slope of 9 percent in native grass. When described the soil was dry below 12 inches. (Colors are for dry soil unless otherwise stated.)
A--0 to 3 inches; dark grayish brown (10YR 4/2) loam, very dark grayish brown (10YR 3/2) moist; weak medium granular structure; soft, very friable; neutral; clear smooth boundary. (3 to 5 inches thick)
Bw--3 to 11 inches; dark grayish brown (10YR 4/2) fine sandy loam, very dark grayish brown (10YR 3/2) moist; weak coarse prismatic structure; slightly hard, friable; slightly alkaline; abrupt wavy boundary. (7 to 15 inches thick)
Bk1--11 to 16 inches; brown (10YR 5/3) fine sandy loam, dark brown (10YR 4/3) moist; weak coarse prismatic structure; slightly hard, friable; many fine accumulations of carbonate; strong effervescence; moderately alkaline; clear wavy boundary.
Bk2--16 to 24 inches; brown (10YR 5/3) sandy loam, dark brown (10YR 4/3) moist; massive, soft, very friable; common fine accumulations of carbonate; strong effervescence; moderately alkaline; gradual wavy boundary. (Combined Bk horizon is 5 to 20 inches thick.)
2C--24 to 60 inches; pale brown (10YR 6/3) and grayish brown (10YR 5/2) gravelly sand, dark brown (10YR 4/3) and dark grayish brown (10YR 4/2) moist; single grain; loose; slight effervescence; moderately alkaline.
TYPE LOCATION: Hughes County, South Dakota; about 15 miles south and 6 miles west of Harrold; 1,440 feet west and 330 feet south of the NE corner of sec. 29, T. 110 N., R. 75 W.
RANGE IN CHARACTERISTICS: The depth to free carbonates ranges from 10 to 20 inches. The depth to loose sand and gravel typically is about 24 to 28 inches and ranges from 20 to 40 inches. The mollic epipedon ranges from 7 to 15 inches in thickness and typically extends through the Bw horizon.
The A horizon has hue of 10YR, value of 4 or 5 and 2 or 3 moist, and chroma of 2 moist. It typically is loam, but includes silt loam and fine sandy loam. It has weak thick platy or fine or medium granular structure. It is slightly acid or neutral.
The Bw horizon has hue of 10YR or 2.5Y, value of 4 or 5 and 2 or 3 moist, and chroma of 2 or 3. It is a loam or fine sandy loam averaging less than 18 percent clay. It is neutral or slightly alkaline.
The Bk horizon has hue of 10YR or 2.5Y, value of 5 or 6 and 4 or 5 moist, and chroma of 2 or 3. It is fine sandy loam, sandy loam, loam, or gravelly sandy loam. It has common to many fine and medium accumulations of carbonate. It is slightly or moderately alkaline. It contains as much 15 percent gravel by volume in the lower part.
The C horizon, if present, has hue of 10YR or 2.5Y, value of 5 to 7 and 4 to 6 moist, and chroma of 2 to 4. It is fine sandy loam, sandy loam, loam or gravelly sandy loam. It contains as much as 20 percent gravel by volume. It is slightly or moderately alkaline.
The 2C horizon is multi-colored loose medium or coarse sand and gravel containing carbonates. It is sand or loamy sand containing 20 to 60 percent gravel by volume. It is slightly or moderately alkaline.
COMPETING SERIES: These are the Anselmo and Caval series. The Anselmo soils do not have 2C horizons of sand and gravel. Caval soils are leached of carbonates throughout.
GEOGRAPHIC SETTING: Orton soils are on nearly level to moderately steep terraces or terrace remnants that cap ridges, crests, and upper slopes on undulating or rolling terrain. Surfaces are plane or convex with slope gradients ranging from 0 to 25 percent. The soils formed in loamy alluvium or outwash sediments overlying sand and gravel. Mean annual temperature ranges from 45 to 50 degrees F, and mean annual precipitation ranges from 17 to 24 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Betts, Canning, Glenham, Java, Lowry, Oahe, Ree, and Sully soils. Betts, Glenham, and Java soils have a fine-loamy control section and formed in glacial till on uplands. Canning and Ree soils have fine-loamy argillic horizons and are on similar topographic positions. Lowry and Sully soils are on similar topographic positions and have a coarse-silty control section. Oahe soils are on smoother landscapes and are fine-loamy over sandy skeletal.
DRAINAGE AND PERMEABILITY: Well drained. Runoff is low on level areas to high on steep slopes. Permeability is moderate or moderately rapid in the solum and rapid in the sand and gravel substratum.
USE AND VEGETATION: Mostly in native range. Principal species are little bluestem, western wheatgrass, prairie sandreed, needleandthread, sideoats grama, threadleaf sedge, blue grama, and forbs. Small grain, sorghum, and alfalfa are the principal cultivated crops.
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, 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 11 inches (A and Bw horizons).