LOCATION CASTLEWOOD SDEstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Cumulic Vertic Endoaquolls
TYPICAL PEDON: Castlewood silty clay, on a slightly concave slopes of less than 1 percent in a cultivated field. When described the soil was moist throughout. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 8 inches; black (10YR 2/1) silty clay, very dark gray (10YR 3/1) dry; moderate fine and medium granular structure; slightly hard, friable, sticky and plastic; neutral; abrupt smooth boundary.
A--8 to 13 inches; black (5Y 2/1) silty clay, very dark gray (5Y 3/1) dry; moderate medium subangular blocky structure parting to moderate fine and medium granular; very hard, firm, sticky and plastic; neutral; clear smooth boundary. (Combined A horizon thickness is 8 to 22 inches.)
Bg1--13 to 25 inches; black (5Y 2/1) clay, very dark gray (5Y 3/1) dry; moderate medium and coarse prismatic structure parting to moderate medium subangular blocky; very hard, firm, sticky and plastic; neutral; clear smooth boundary.
Bg2--25 to 34 inches; black (5Y 2/1) clay, dark gray (5Y 4/1) dry; moderate medium and coarse prismatic structure parting to moderate medium subangular blocky; very hard, firm, sticky and plastic; mildly alkaline; clear wavy boundary.
Bg3--34 to 46 inches; very dark gray (5Y 3/1) clay, gray (5Y 5/1) dry; common fine prominent brown (7.5YR 4/2) mottles; moderate medium and coarse prismatic structure parting to moderate medium subangular blocky; very hard, firm, sticky and plastic; mildly alkaline; clear wavy boundary.
Bg4--46 to 55 inches; dark olive gray (5Y 3/2) clay loam, olive gray (5Y 5/2) dry; common fine and medium prominent dark yellowish brown (10YR 4/4) mottles; moderate coarse prismatic structure parting to moderate coarse subangular blocky; very hard, firm, slightly sticky and slightly plastic; few fine iron and manganese oxide accumulations; mildly alkaline; clear wavy boundary. (Combined B horizon thickness is 29 to 43 inches.)
Bkg--55 to 60 inches; olive gray (5Y 4/2) silty clay loam, light olive gray (5Y 6/2) dry; common fine and medium prominent dark yellowish brown (10YR 4/4) mottles; moderate coarse subangular blocky structure; hard, firm, slightly sticky and slightly plastic; common fine accumulations of calcium carbonate; few fine iron and manganese oxide accumulations; strong effervescence; mildly alkaline.
TYPE LOCATION: Deuel County, South Dakota; about 2 1/2 miles east and 1/2 mile south of Estelline; 2150 feet north and 750 feet west of the southeast corner of sec. 29, T. 113 N., R. 50 W.
RANGE IN CHARACTERISTICS: Thickness of the mollic epipedon ranges from 24 to over 60 inches. The depth to free calcium carbonate ranges from 15 to over 60 inches. The control section has from 35 to 50 percent clay. Total sand in the 10 to 40 inch particle-size control section ranges from 15 to 30 percent. It also has less than 15 percent fine sand or coarser. Buried horizons are present in some pedons.
The A horizon is neutral or has hue of 10YR to 5Y, value of 2 or 3 (3 or 4 dry), and chroma of 1 or less. It typically is silty clay, clay, or silty clay loam but is clay loam in some pedons. It is moderately acid or neutral.
The Bg or Bw horizon is neutral or has hue of 2.5Y or 5Y, value of 2 to 5 (3 to 6 dry), and chroma of 1 or 2. It is clay, silty clay, silty clay loam, or clay loam. It is neutral or mildly alkaline. Some pedons have a Bk horizon.
The Ab horizon, where present, has hue of 5Y, value of 2 or 3 (3 to 5 dry). It is silty clay, clay, or silty clay loam.
The Bkg horizon has hue of 2.5Y or 5Y, values of 4 to 6 (5 to 7 dry), and chroma of 1 to 3. It typically is silty clay loam, silty clay, clay, or clay loam but coarser strata are present in some pedons. Some pedons have sandy loam or gravelly sandy loam C horizons below depths of 40 inches. It is mildly or moderately alkaline. Some pedons have Cg horizons.
COMPETING SERIES: These are the Crooked Creek, Dovray, and Hutton series. Crooked Creek soils have redoximorphic within 30 inches and are drier in the soil moisture control section during the 120 days following the summer solstice. Hutton soils do not have a cambic horizon and are at a higher elevation and are drier in the soil moisture control section. Dovray soils have less than 15 percent sand in the 10 to 40 inch part of the control section.
GEOGRAPHIC SETTING: Castlewood soils are on flood plains. They receive floodwater from stream overflow or from adjacent uplands. Surfaces are plane to concave with slope gradients less than 1 percent. Castlewood soils formed in clayey alluvium. Mean annual temperature ranges from 45 to 47 degrees F. and mean annual precipitation ranges from 20 to 24 inches. Elevation is 950 to 1650 feet. Average growing season is 120 to 130 days; average growing season precipitation is 16 to 18 inches; and average growing degree days is 2500 to 2800.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Darnen, Divide, LaDelle, Lamoure, La Prairie, Lowe, Ludden, and Moritz soils. Ludden soils have carbonates throughout and are on similar positions. Darnen, Divide, LaDelle, Lamoure, La Prairie, Lowe, and Moritz soils contain less than 35 percent clay in the series control section. In addition, Darnen soils are better drained and are on footslopes and alluvial fans adjacent to the uplands. Divide soils have calcic horizons and are underlain by gravelly material at depths between 20 and 40 inches. LaDelle soils have a fine-silty series control section. La Prairie soils have a fine-loamy series control section. LaDelle and La Prairie soils are better drained and are closer to the stream channel. Lowe and Moritz soils have calcic horizons within a depth of 16 inches and are on higher parts of the floodplain.
DRAINAGE AND PERMEABILITY: Poorly drained. Runoff is very slow. Permeability is slow. Castlewood soils are subject to occasional or frequent flooding. Water table depth ranges from 0 to 2 feet, especially in the spring.
USE AND VEGETATION: Mostly cultivated. Corn, soybeans, small grains, alfalfa, and tame grass are the principal crops. Major native species are prairie cordgrass, reedgrasses, reed canarygrass, sand bluestem, sedges, and forbs.
DISTRIBUTION AND EXTENT: Northeastern South Dakota; possibly adjacent parts of North Dakota and Minnesota. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES PROPOSED: Deuel County, South Dakota 1988. The name is of a town in eastern Hamlin County.
REMARKS: Diagnostic horizons and features recognized in this pedon are: Mollic epipedon - the zone from the surface to a depth of about 55 inches (Ap, A, Bw1, Bw2, Bw3, Bw4 horizons). Aquic criteria - chroma of 2 or less and distinct or prominent mottles in the lower part of the mollic epipedon; Vertic criteria - a linear extensibility of more than 6 cm in the upper 100 cm.
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