LOCATION WAKONDA SDEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Aeric Calciaquolls
TYPICAL PEDON: Wakonda silt loam, on a slightly convex, northeast-facing slope of 1 percent, in a cultivated field. When described the soil was moist to 32 inches and wet below. (Colors are for dry soil unless otherwise stated.)
Ap--0 to 9 inches; grayish brown (10YR 5/2) silt loam, very dark grayish brown (10YR 3/2) moist; weak fine and medium subangular blocky structure parting to weak fine granular; hard, friable, slightly sticky and slightly plastic; common fine and many very fine roots throughout; few very fine tubular pores; strongly effervescent; slightly alkaline; abrupt smooth boundary. (7 to 16 inches thick)
Bky1--9 to 18 inches; light brownish gray (2.5Y 6/2) silt loam, dark grayish brown (2.5Y 4/2) moist; few fine distinct dark yellowish brown (10YR 4/4) redoximorphic accumulations; weak medium subangular blocky structure; hard, very friable, slightly sticky and slightly plastic; few fine and common very fine roots throughout; common very fine tubular pores; common fine and few medium soft masses of gypsum; common fine and few medium soft masses of calcium carbonate; violently effervescent; moderately alkaline; clear wavy boundary.
Bky2--18 to 30 inches; light yellowish brown (2.5Y 6/3) silt loam, olive brown (2.5Y 4/3) moist; common fine prominent yellowish brown (10YR 5/6), few fine prominent strong brown (7.5YR 5/8) redoximorphic accumulations, and few fine distinct gray (2.5Y 5/1) redoximorphic depletions; weak medium subangular blocky structure; hard, very friable, slightly sticky and slightly plastic; few very fine roots throughout; few fine and common very fine tubular pores; common fine and few medium soft masses of gypsum; few fine soft iron-manganese concretions; many fine and few medium soft masses of calcium carbonate; violently effervescent; moderately alkaline; gradual wavy boundary.
Bky3--30 to 35 inches; pale yellow (2.5Y 7/3) silt loam, light olive brown (2.5Y 5/3) moist; many fine prominent yellowish brown (10YR 5/6), common fine prominent strong brown (7.5YR 5/8) redoximorphic accumulations, and common fine distinct gray (2.5Y 5/1) redoximorphic depletions; weak medium subangular blocky structure; hard, very friable, slightly sticky and slightly plastic; few very fine roots throughout; few fine and many very fine tubular pores; many fine and few medium soft masses of gypsum; few fine soft iron-manganese concretions; many fine and few medium soft masses of calcium carbonate; violently effervescent; moderately alkaline; clear smooth boundary. (Combined thickness of the Bky horizon is 16 to 32 inches.)
Cgy1--35 to 62 inches; light gray (5Y 7/2) silt loam, olive gray (5Y 5/2) moist; common fine and medium prominent yellowish brown (10YR 5/6), common fine and medium prominent strong brown (7.5YR 5/8) redoximorphic accumulations, and common fine distinct gray (2.5Y 5/1) redoximorphic depletions; massive; hard, friable, slightly sticky and slightly plastic; common very fine tubular pores; many fine and few medium nests of gypsum; common fine soft iron-manganese concretions; few fine calcium carbonate concretions; violently effervescent; moderately alkaline; abrupt smooth boundary.
2Cgy2--62 to 80 inches; pale yellow (2.5Y 7/3) loam, light olive brown (2.5Y 5/3) moist; many fine and medium prominent yellowish brown (10YR 5/6), common fine and medium prominent strong brown (7.5YR 5/8) redoximorphic accumulations, and common fine and medium distinct gray (2.5Y 5/1) redoximorphic depletions; massive; very hard, firm, slightly sticky and slightly plastic; common very fine tubular pores; common fine soft masses of gypsum; common fine and medium hard carbonate concretions; violently effervescent; moderately alkaline.
TYPE LOCATION: Clay County, South Dakota; about 4 miles north and 1/2 mile west of Vermillion; located about 148 feet south and 350 feet west of the northeast corner of sec. 27, T. 93 N., R. 52 W.; USGS Vermillion topographic quadrangle; lat. 42 degrees 51 minutes 05 seconds N. and long. 96 degrees 57 minutes 55 seconds W., NAD 83.
RANGE IN CHARACTERISTICS: The thickness of the solum ranges from 25 to 45 inches. The thickness of the mollic epipedon ranges from 7 to 16 inches. The soil typically contains calcium carbonate at the surface, but in places where native grass is the ground cover some pedons are leached to depths of 6 inches. Electrical conductivity of the saturation extract ranges from 1 to 4 mmhos/cm in the upper 6 inches, and 4 to 8 mmhos/cm below depths of 6 inches. The soil contains up to 5 percent by volume of pebbles.
The A horizon has hue of 10YR, value of 3 to 5 and 2 or 3 moist, and chroma of 1 or 2. It typically is silt loam, but is loam or silty clay loam in some pedons. It ranges from neutral to moderately alkaline.
The B horizon has hue of 10YR or 2.5Y, value of 5 to 7 and 3 to 5 moist, and chroma of 2 to 4. It typically has few or common distinct redoximorphic features in the lower part. It is silt loam or silty clay loam. It contains from about 16 to 35 percent calcium carbonate equivalent and is slightly alkaline or moderately alkaline. Secondary calcium carbonate occurs as few to many, fine or medium accumulations. Gypsum occurs as few or common nests and crystals in most pedons. Faint mottles are in the B horizon, but distinct or prominent redoximorphic features typically are below depths of 18 inches.
The C horizons have hue to 2.5Y or 5Y, value to 5 to 7 and 4 to 6 moist, and chroma of 1 to 4. Redoximorphic features range from few to many, fine or medium, distinct or prominent. The C horizons typically are silt loam or silty clay loam, but are sandy loam, loam, and clay loam below depths of 40 inches in some pedons. They are slightly or moderately alkaline. Some pedons do not have accumulations of gypsum.
COMPETING SERIES: This is the Firesteel series. Firesteel soils have sola terminated by siltstone at depths of 24 to 40 inches.
GEOGRAPHIC SETTING: Wakonda soils are on nearly level to gently undulating silty mantled glacial till plains. They are on slight convex rises on flats and on the convex to plain side slopes surrounding depressions. Slopes are short with gradients of less than 3 percent. The soil formed in silty sediments derived from loess or silty glacial drift. Mean annual air temperature ranges from 45 to 52 degrees F. Mean annual precipitation ranges from 20 to 26 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Chancellor, Egan, Moody, Nora, Tetonka, Trent, Viborg, Wentworth, Whitewood, and Worthing soils. All of these soils do not have a calcic horizon near the surface. In addition, Chancellor soils are fine textured and are in nearby swales. Egan, Moody, Nora, and Wentworth soils are well drained and are on nearby higher positions. Tetonka soils have E horizons and argillic horizons and are in depressions. Trent, Viborg, and Whitewood soils have thick mollic epipedons and are in swales and concave positions. Worthing soils are fine, have argillic horizons, and are in depressions.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained. Surface runoff is low. Permeability is moderate. Subsoil drainage is affected by the capillary rise of water from a seasonal water table at 1.5 to 2.5 feet which concentrates lime, gypsum, and other salts in the B horizons.
USE AND VEGETATION: Most areas are used to grow corn, soybeans, small grain, and alfalfa. Principal native grasses are big bluestem, indiangrass, little bluestem, needlegrasses, and sedges.
DISTRIBUTION AND EXTENT: Southeastern South Dakota. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Clay County, South Dakota, 1953.
REMARKS: Diagnostic horizons and features recognized in this pedon are: mollic epipedon - zone from the surface of the soil to a depth of 9 inches (Ap horizon); calcic horizon - the zone from a depth of about 9 to 35 inches (Bky1, Bky2, and Bky3 horizons).
The previous classification was fine-silty, mixed, mesic Aquic Calciustolls. The change in classification was based on an MLRA correlation.