LOCATION BENCLARE SD+IAEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Udertic Haplustolls
TYPICAL PEDON: Benclare silty clay loam - on a plane, north-facing slope of 1 percent in a cultivated field. When described the soil was moist throughout. (Colors are for dry soil unless otherwise stated.)
Ap--0 to 8 inches; dark gray (10YR 4/1) silty clay loam, black (10YR 2/1) moist; weak medium subangular blocky structure parting to moderate fine granular; hard, friable, slightly sticky and slightly plastic; common very fine roots throughout; common very fine vesicular pores; moderately acid; abrupt smooth boundary. (6 to 20 inches thick)
Bw1--8 to 15 inches; dark gray (10YR 4/1) silty clay, black (10YR 2/1) moist; weak medium and coarse prismatic structure parting to moderate fine subangular blocky; hard, firm, sticky and plastic; common very fine roots throughout; common very fine tubular pores; very few patchy pressure faces; few worm casts; slightly acid; gradual wavy boundary.
Bw2--15 to 24 inches; grayish brown (10YR 5/2) and dark gray (10YR 4/1) silty clay, very dark gray (10YR 3/1) and very dark grayish brown (10YR 3/2) moist; moderate medium prismatic structure parting to strong very fine and fine subangular blocky; hard, firm, sticky and plastic; common very fine roots throughout; common fine tubular pores; very few patchy pressure faces; few worm casts; slightly acid; gradual wavy boundary.
Bw3--24 to 31 inches; grayish brown (2.5Y 5/2) silty clay, very dark grayish brown (2.5Y 3/2) moist; moderate medium prismatic structure parting to strong fine and medium subangular blocky; very hard, very firm, sticky and plastic; common very fine tubular pores; very few discontinuous pressure faces; neutral; clear wavy boundary. (Combined thickness of the Bw horizon is 10 to 45 inches)
Bk1--31 to 42 inches; light brownish gray (2.5Y 6/2) silty clay, grayish brown (2.5Y 5/2) moist; few fine distinct very dark gray (5Y 3/1) moist mottles; weak medium and coarse prismatic structure parting to moderate fine and medium subangular blocky; very hard, very firm, sticky and plastic; common very fine tubular pores; 7.0 percent calcium carbonate equivalent; common fine and medium rounded soft masses of calcium carbonate; strongly effervescent; slightly alkaline; gradual wavy boundary.
Bk2--42 to 52 inches; pale olive (5Y 6/3) clay, olive (5Y 5/3) moist; common fine distinct dark gray (5Y 4/1) moist redox depletions and common fine prominent light olive brown (2.5Y 5/6) moist redox concentrations; moderate coarse subangular blocky structure parting to moderate medium subangular blocky; very hard, very firm, sticky and plastic; common very fine tubular pores; 15.0 percent calcium carbonate equivalent; very few discontinuous pressure faces; common medium rounded soft masses of carbonate; violently effervescent; moderately alkaline; gradual wavy boundary. (Combined thickness of the Bk horizon is 10 to 25 inches)
C--52 to 80 inches; pale yellow (5Y 7/3) clay, pale olive (5Y 6/3) moist; many fine and medium distinct gray (5Y 5/1) moist redox depletions; massive; very hard, very firm, sticky and plastic; common very fine tubular pores; 20.0 percent calcium carbonate equivalent; violently effervescent; moderately alkaline.
TYPE LOCATION: Minnehaha County, South Dakota; about 3 miles west and 1 mile south of Valley Springs; 110 feet north and 515 feet east of the southwest corner of sec. 6, T. 101 N., R. 47 W.; USGS Brandon, SD topographic quadrangle; lat. 43 degrees 34 minutes 24 seconds N. and long. 96 degrees 31 minutes 48 seconds W.
RANGE IN CHARACTERISTICS: Depth to calcium carbonate typically is 30 to 40 inches, but ranges from 24 to 60 inches or more. Thickness of the mollic epipedon typically is 20 to 30 inches but ranges from 20 to 50 inches and extends into the Bw horizon. The control section contains 35 to 50 percent clay.
The A horizon has hue of 10YR, value of 2 to 4 and 2 or 3 moist, and chroma of 1 or 2. It typically is silty clay loam, but some pedons are silty clay. It ranges from moderately acid to neutral.
The Bw horizon has hue of 10YR, 2.5Y, or 5Y; value of 3 to 5 and 2 to 4 moist; and chroma of 1 to 3. Hue of 5Y is only in the lower part. It is silty clay loam or silty clay. It is slightly acid or neutral. Few or common faint and distinct redox features in the lower part of some pedons.
The Bk horizon has hue of 10YR, 2.5Y, or 5Y; value of 5 to 7 and 4 to 6 moist; and chroma of 1 to 3. It is silty clay loam, clay, or silty clay. It is neutral to moderately alkaline. Some pedons have a BC horizon.
The C horizon has hue of 2.5Y or 5Y, value of 5 to 7 and 4 to 6 moist, and chroma of 1 to 3. It is silty clay loam, silty clay, or clay. It typically is slightly alkaline or moderately alkaline, but ranges from slightly acid to moderately alkaline. Faint and distinct redox features are few to many. Some pedons do not have accumulations of carbonate. Thin strata of coarser textures are below depths of 40 inches in some pedons.
COMPETING SERIES: These are the Corson, Rosehill, and Sutphen series. Corson soils have mollic epipedons less than 20 inches thick. Rosehill and Sutphen soils have soil temperatures at a depth of 20 inches that average more than 51 degrees F. Also, Rosehill soils have a paralithic contact at depths of 20 to 40 inches.
GEOGRAPHIC SETTING: The Benclare soils are on nearly level terraces. Surfaces are concave or plane, and slope gradients typically are 2 percent or less. The soil formed in clayey lacustrine materials. The mean annual temperature ranges from 45 to 49 degrees F. Mean annual precipitation ranges from 20 to 26 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Alcester, Chancellor, Clamo, Clarno, Corson, Crofton, Graceville, Luton, Moody, and Nora soils. The well drained Corson, Clarno, Crofton, Moody, and Nora soils are on adjacent uplands. Corson soils have a mollic epipedon less than 20 inches thick. The fine-silty Alcester soils are on fans and foot slopes, stream terraces, and flood plains. The somewhat poorly drained Chancellor soils are on toe slopes positions below the Benclare soils. The poorly drained Clamo and Luton soils are below Benclare soils on flood plains. The fine-silty Graceville soils are on terraces and adjacent uplands.
DRAINAGE AND PERMEABILITY: Moderately well drained or somewhat poorly drained. Surface runoff is slow or medium. Permeability is slow. Depth to water table ranges from 1.5 to 5 feet. Most areas are subject to overland flow.
USE AND VEGETATION: Mostly used to grow corn, oats, soybeans, and alfalfa. Principal native grasses are big bluestem, little bluestem, green needlegrass, switchgrass, and western wheatgrass.
DISTRIBUTION AND EXTENT: Southeastern South Dakota and northwestern Iowa. The series is moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Minnehaha County, South Dakota, 1961.
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 24 inches (Ap, Bw1, Bw2 horizons); Vertic properties - a linear extensibility of greater than 6.0 in the upper 100 cm.
ADDITIONAL DATA: Laboratory data for two profiles are in the Minnehaha County Soil Report, issued June, 1964 (S57SD-50-6 (1-9) and S57SD-50-7(1-9)).