LOCATION KADOKA SD+NE WYEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Aridic Argiustolls
TYPICAL PEDON: Kadoka silt loam - on a convex slope of 5 percent in native grass. When described, the soil was dry throughout. (Colors are for dry soil unless otherwise stated.)
A--0 to 4 inches; grayish brown (10YR 5/2) silt loam, very dark grayish brown (10YR 3/2) moist; weak medium subangular blocky structure parting to moderate fine granular; soft, friable; neutral; clear wavy boundary. (3 to 7 inches thick)
Bt1--4 to 8 inches; grayish brown (10YR 5/2) silty clay loam, very dark grayish brown (10YR 3/2) moist; weak fine and medium prismatic structure parting to moderate fine and medium subangular blocky; slightly hard, friable; thin shiny coatings on faces of peds; neutral; clear wavy boundary.
Bt2--8 to 14 inches, brown (10YR 5/3) silty clay loam, brown (10YR 4/3) moist; weak medium prismatic structure parting to moderate medium and fine blocky; hard, firm; shiny coatings on faces of peds; slightly alkaline; clear wavy boundary. (Combined Bt horizon is 6 to 13 inches thick)
Bw--14 to 22 inches; pale brown (10YR 6/3) silt loam, brown (10YR 5/3) moist; weak medium and coarse prismatic structure parting to weak medium subangular blocky; slightly hard, friable; slightly alkaline; gradual irregular boundary. (0 to 8 inches thick)
Bk--22 to 34 inches; pinkish white (7.5YR 8/2) and pinkish gray (7.5YR 7/2) silt loam, pale brown (10YR 6/3) moist; weak fine and medium subangular blocky structure; soft, friable; fragments of siltstone make up 15 percent by volume; rock structure evident; common fine accumulations of carbonate; strong effervescence; moderately alkaline; gradual irregular boundary. (5 to 18 inches thick)
Cr--34 to 45 inches; pinkish white (7.5YR 8/2) bedded siltstone, light brown (7.5YR 6/3) moist; massive; strong effervescence; few fine accumulations of carbonate on surfaces of fragments of rock.
TYPE LOCATION: Jackson County, South Dakota; about 4 miles north and 2 1/2 miles east of Long Valley, 2115 feet east and 150 feet south of the northwest corner of sec. 22, T. 41 N., R. 35 W.
RANGE IN CHARACTERISTICS: Depth to bedrock typically is 20 to 30 inches, but ranges to 40 inches. Thickness of the mollic epipedon ranges from 7 to 16 inches and extends into the Bt horizon. Depth to carbonates ranges from 10 to 28 inches. Glass shards are throughout and average 10 to 35 percent of the volume. CEC ranges from 125 meq./100g of clay in the upper part of the solum to over 550 meq/100g of clay in the bedrock. The 15-bar clay-water ratio exceeds 1.
The A horizon has hue of 10YR, value of 4 or 5 and 2 or 3 moist, and chroma of 2. It is silt loam or loam. It is neutral or slightly alkaline.
The Bt and Bw horizon has hue of 7.5YR or 10YR, value of 4 to 6 and 3 to 5 moist, and chroma of 2 to 4. They typically are silty clay loam or silt loam averaging between 25 and 35 percent clay, but some pedons are loam. Reaction is neutral to moderately alkaline. Few to common fragments of siltstone of 1 to 10 mm are in the lower Bt and Bw horizons of most pedons. Some pedons have BC horizons.
The Bk horizon typically has hue of 7.5YR or 10YR, value of 6 to 8 and 5 to 7 moist, and chroma of 2 to 4. It is silt loam or loam. Fragments of siltstone make up 5 to 40 percent by volume and are coated with carbonates in some pedons. It is slightly alkaline to strongly alkaline. Some pedons have C horizons.
The Cr horizon is siltstone bedrock. It is soft and easily dug with a spade. It fractures into plates and fragments 1/4 to 3 inches thick. It is slightly alkaline or moderately alkaline.
COMPETING SERIES: These are the Alliance, Beauvais, Cale, Keith, Mace, Norka, and Vale series in the same family and the Agar, Duroc, Huggins, Keota, Kube, Rosebud, Savo, and Shena series. The Alliance, Beauvais, Cale, Keith, Norka, and Vale series do not have bedrock within a depth of 40 inches. Mace soils are moderately deep over Ogallala material. Agar soils are dry for a shorter period. Duroc soils have mollic epipedons greater than 20 inches thick. The Huggins, Kube, and Savo soils are fine textured. Rosebud soils are fine-loamy. The Keota soils do not have a mollic epipedon or argillic horizon. Shena soils have bedrock at depths less than 17 inches.
GEOGRAPHIC SETTING: Kadoka soils are nearly level to moderately steep on uplands with convex to smooth surfaces having slope gradients of 0 to 15 percent. The soils formed in silty residuum weathered mainly from siltstone or very fine grained sandstone. Mean annual temperature ranges from 45 to 49 degrees F; mean annual precipitation ranges from 12 to 18 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Duroc, Huggins, Keith, Keota, Kube, and Shena soils and the Epping, Goshen, Wanblee, and Wortman soils. Duroc and Goshen have a mollic epipedon thicker than 20 inches and are in swales. Epping and Keota soils are on the more convex steeper parts of the landscape. Epping soils have siltstone at depths less than 20 inches. Huggins, Keith, Kube, and Shena soils are in similar landscapes. Wanblee and Wortman soils are on nearly level nearby landscapes and have a natric horizon.
DRAINAGE AND PERMEABILITY: Well drained. Surface runoff is slow on 0 to 2 percent slopes and medium on 2 to 15 percent slopes. Permeability is moderate in the soil above the bedrock.
USE AND VEGETATION: Major use is as rangeland. Cultivated areas are cropped to small grain and alfalfa. Western wheatgrass, blue grama, green needlegrass, needleandthread, big bluestem, and sideoats grama are the main grasses.
DISTRIBUTION AND EXTENT: The series is of large extent. Southwestern South Dakota and southeastern Wyoming.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Washabaugh County, South Dakota, 6/70.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the zone from the surface of the soil to a depth of about 8 inches. (A & Bt1 horizons)
Argillic horizon - the zone from about 4 to 14 inches (Bt1, Bt2 horizons)