LOCATION ATHELWOLD SD+MNEstablished Series
TAXONOMIC CLASS: Fine-silty over sandy or sandy-skeletal, mixed, superactive, frigid Pachic Hapludolls
TYPICAL PEDON: Athelwold silty clay loam - on a 1 percent slope in a cultivated field. (Colors are for dry soil unless otherwise stated.)
Ap--0 to 8 inches; very dark gray (10YR 3/1) silty clay loam, black (10YR 2/1) moist; weak fine granular structure; hard, very friable, slightly sticky and slightly plastic; few worm casts; common fine roots; medium acid; abrupt smooth boundary.
A--8 to 17 inches; very dark gray (10YR 3/1) silty clay loam, black (10YR 2/1) moist; weak and moderate fine and medium granular structure; hard, very friable, slightly sticky and slightly plastic; few worm casts; few fine roots; slightly acid; clear smooth boundary. (Combined thickness of the A horizons is 10 to 18 inches.)
Bw1--17 to 25 inches; grayish brown (2.5Y 5/2) silty clay loam, very dark grayish brown (2.5Y 3/2) moist; weak medium prismatic structure parting to moderate very fine and fine subangular blocky; hard, friable, slightly sticky and slightly plastic; few fine roots; neutral; gradual smooth boundary.
Bw2--25 to 30 inches; light brownish gray (2.5Y 6/2) silty clay loam, dark grayish brown (2.5Y 4/2) moist; few faint mottles of brownish yellow (10YR 6/6) and light gray (5Y 7/1) moist; weak medium prismatic structure parting to weak medium and fine subangular blocky; hard, friable, slightly sticky and slightly plastic; neutral; abrupt wavy boundary. (Combined Bw horizons is 6 to 16 inches thick.)
Bk--30 to 36 inches; light gray (5Y 7/2) silty clay loam, olive gray (5Y 5/2) moist; few fine distinct mottles of brownish yellow (10YR 6/6) moist; weak medium and coarse subangular blocky structure; hard, very friable; slightly sticky and slightly plastic; many fine and medium accumulations of carbonate; few fine carbonate concretions; strong effervescence; moderately alkaline; gradual wavy boundary. (3 to 10 inches thick)
2C--36 to 60 inches; multicolored sand and gravel; single grained; loose; slight effervescence; mildly alkaline.
TYPE LOCATION: Brookings County, South Dakota; about 4 1/2 miles south of Volga; 2600 feet south and 60 feet east from the northwest corner of sec. 12, T. 109 N., R. 51 W.
RANGE IN CHARACTERISTICS: Depth to carbonates ranges from 16 to 34 inches. Depth to sand and gravel typically is about 36 inches and ranges from 20 to 40 inches. The mollic epipedon is 16 to 28 inches thick and extends into the Bw horizon in many pedons. The control section contains 25 to 35 percent clay and less than 15 percent sand that is fine sand or coarser in the upper part.
The A horizon has hue of 10YR, value of 3 or 4 and 2 or 3 moist, and chroma of 1.5 or less in the upper part and 1 or 2 in the lower part. Typically, it is silty clay loam, but some pedons are silt loam. It ranges from neutral to medium acid.
The Bw horizon has hue of 10YR or 2.5Y, value of 4 to 7 and 3 to 5 moist, and chroma of 2 to 4. Typically, it is silty clay loam, but some pedons are silt loam. Most pedons have few faint mottles in the lower part. It is neutral or mildly alkaline.
The Bk horizon has hue of 2.5Y or 5Y, value of 6 to 8 and 5 or 6 moist, and chroma of 2 to 4. It is silt loam, silty clay loam, or sandy clay loam and has few to many faint or distinct mottles. It has common or many, fine or medium accumulations of carbonate and few to common fine carbonate concretions. It is mildly alkaline or moderately alkaline. Some pedons have C horizons that have color and texture of the Bk horizon.
The 2C horizon is calcareous, multicolored, stratified sand and gravel in hue of 10YR or 2.5Y. It contains 20 to 60 percent gravel by volume. It is mildly alkaline or moderately alkaline.
COMPETING SERIES: This is the Estelline series in the same family. Estelline soils lack mottles above a depth of 40 inches and are well drained.
GEOGRAPHIC SETTING: Athelwold soils are on flats and in slightly depressed drainageways on level or nearly level stream terraces and outwash plains. Surfaces are plane to slightly concave and slope gradients range from 0 to 2 percent. Athelwold soils formed in silty material overlying outwash sand and gravel. Mean annual temperature ranges from 38 to 45 degrees F, and the mean annual precipitation ranges from 18 to 24 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: This is the competing Estelline soils and the Trosky soils. Estelline soils are above the depressed drainageways. The poorly drained Trosky soils are on lower parts of the landscape below the Athelwold soils.
DRAINAGE AND PERMEABILITY: Moderately well drained; runoff is slow; permeability is moderate in the solum and rapid in the underlying sand and gravel. It has a temporary water table between depths of 2 1/2 and 5 feet in the spring of most years. Some areas are flooded for short periods by run in from adjacent slopes.
USE AND VEGETATION: Mostly cultivated. The main crops are corn, small grain, and alfalfa. Native vegetation is big bluestem, green needlegrass, western wheatgrass, sideoats grama, sedges, and forbs.
DISTRIBUTION AND EXTENT: Northeastern South Dakota and adjoining parts of Minnesota. It is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Brookings County, South Dakota, 1956.
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 25 inches (Ap, A, Bw1 horizons).