LOCATION WALKE SDEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Glossic Natrustolls
TYPICAL PEDON: Walke silt loam - on a plane slope of less than 1 percent in native grass. (Colors are for dry soil unless otherwise stated.)
A1--0 to 3 inches; dark gray (10YR 4/1) silt loam, very dark gray (10YR 3/1) moist; weak medium granular structure; soft, very friable; neutral; clear smooth boundary.
A2--3 to 7 inches; dark gray (10YR 4/1) silt loam, very dark gray (10YR 3/1) moist; weak medium and fine subangular blocky structure parting to weak medium granular; soft, very friable; neutral; clear smooth boundary. (Combined A horizons is 5 to 10 inches thick.)
B/E--7 to 9 inches; dark grayish brown (10YR 4/2) silty clay loam (B), very dark grayish brown (10YR 3/2) moist and patchy gray (10YR 6/1) silt loam coatings on vertical faces of peds; moderate medium blocky structure; hard, firm, sticky and slightly plastic; neutral; clear smooth boundary. (2 to 4 inches thick)
Btn--9 to 15 inches; dark grayish brown (10YR 4/2) silty clay loam, very dark grayish brown (10YR 3/2) moist; moderate coarse prismatic structure parting to strong medium subangular blocky; hard, firm, sticky and plastic; few thin clay films on faces of peds; slightly alkaline; clear smooth boundary. (5 to 12 inches thick)
Bk1--15 to 26 inches; light yellowish brown (2.5Y 6/3) silty clay loam, olive brown (2.5Y 4/3) moist; weak coarse prismatic structure parting to weak medium subangular blocky; hard, firm, slightly sticky and slightly plastic; few accumulations of carbonate; strong effervescence; moderately alkaline; abrupt smooth boundary. (5 to 14 inches thick)
2Bk2--26 to 45 inches; light brownish gray (2.5Y 6/2) clay loam, grayish brown (2.5Y 5/2) moist; weak coarse subangular blocky structure; very hard, firm, sticky and plastic; common accumulations of carbonate; strong effervescence; moderately alkaline; abrupt smooth boundary. (0 to 25 inches thick)
2By--45 to 60 inches; gray (5Y 5/1) clay loam, very dark gray (5Y 3/1) moist; weak medium and coarse subangular blocky structure; very hard, firm, sticky and plastic; many fine shale fragments; common fine nests of gypsum; strong effervescence; slightly alkaline. (0 to 25 inches thick)
TYPE LOCATION: Sully County, South Dakota; about 6 miles south and 5 miles east of Onida; 542 feet west and 1,564 feet north of the southeast corner of sec. 3, T. 113 N., R. 76 W.
RANGE IN CHARACTERISTICS: Depth to carbonate typically is about 15 inches, but ranges from 12 to 24 inches. Depth to underlying glacial till ranges from 20 to 40 inches. The natric horizon contains an estimated SAR or ESP of 10 to 20.
The A horizon has value of 4 or 5, and 2 or 3 moist, and chroma of 1 or 2. Some pedons have an E horizon.
The B/E horizon has value of 5 or 6 and 3 or 4 moist, and chroma of 1 or 2. It is neutral to moderately alkaline.
The Btn horizon has hue of 10YR or 2.5Y, value of 4 or 5 and 3 or 4 moist, and chroma of 2 or 3. It is silty clay loam or silty clay having a clay content of 35 to 50 percent and less than 15 percent sand coarser than very fine sand. It is neutral to moderately alkaline. Some pedons have a Btk horizon.
The Bk horizon has hue of 10YR or 2.5Y, value of 5 or 6, and 4 or 5 moist, and chroma of 2 to 4. It is silty clay or silty clay loam and neutral to moderately alkaline.
The 2Bk and 2By horizons have hue of 10YR, 2.5Y, or 5Y hue, value of 5 to 7 and 3 to 6 moist, and chroma of 1 to 4. They commonly are clay loam, but are clay in some pedons. They have few to many fine to coarse accumulations of carbonate and are slightly or moderately alkaline. Gypsum and other salts are below horizons of maximum carbonate accumulations. Shale chips range from few to many in the glacial till. Some pedons have a 2C horizon.
COMPETING SERIES: These are the Demky and Stickney soils. Demky soils contain more than 5 percent fine sand or coarser. Stickney soils contain more than 15 percent fine sand or coarser in the solum and have a thicker mollic epipedon.
GEOGRAPHIC SETTING: Walke soils are nearly level on uplands. Slope gradients range from 0 to 3 percent. These soils formed in silty mantles overlying clay loam glacial till. Mean annual temperature ranges from 45 to 49 degrees F, and mean annual precipitation ranges from 15 to 22 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Agar, DeGrey, Eakin, Highmore, Onita, and Raber soils. DeGrey soils have columnar structure in the Bt horizon and are in micro-depressions. Agar, Eakin, Highmore, and Raber soils do not have a natric horizon and are on higher nearby landscapes. Onita soils do not have a natric horizon and are in swales.
DRAINAGE AND PERMEABILITY: Moderately well drained or well drained. Runoff is low. Permeability is moderately slow or slow.
USE AND VEGETATION: Native range and cropland. Crops are mostly alfalfa, corn, and small grain. Native vegetation consists mainly of green needlegrass, western wheatgrass, sideoats grama, blue grama, sedges and forbs.
DISTRIBUTION AND EXTENT: Central and south central South Dakota.
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 15 inches (A1, A2, B/A & Btn horizons); argillic (Natric) horizon - the zone from a depth of about 7 to 15 inches (B/A & Btn horizons)