LOCATION BROOKINGS SD+MNEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, frigid Pachic Hapludolls
TYPICAL PEDON: Brookings silty clay loam on a 2 percent slope in cropland. When described the soil was moist throughout. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 20 centimeters (0 to 8 inches); black (10YR 2/1) silty clay loam, very dark gray (10YR 3/1) dry; weak fine granular structure; slightly hard, friable, slightly sticky, slightly plastic; common fine roots; common very fine pores; slightly acid; abrupt smooth boundary.
A--20 to 43 centimeters (8 to 17 inches); black (10YR 2/1) silty clay loam, very dark gray (10YR 3/1) dry; weak fine and medium and subangular blocky structure parting to weak fine granular; slightly hard, friable, slightly sticky, slightly plastic; common fine roots; common very fine pores; slightly acid; clear wavy boundary. [Combined thickness of the A horizon is 30 to 51 centimeters (12 to 20 inches)].
Bw--43 to 64 centimeters (17 to 25 inches); very dark brown (10YR 2/2) silty clay loam, dark grayish brown (10YR 4/2) dry; weak medium prismatic structure parting to weak fine subangular blocky; slightly hard, friable, slightly sticky, slightly plastic; common very fine roots; common very fine pores; 10 percent worm casts and worm holes; neutral; clear wavy boundary. [Bw horizon thickness is 20 to 64 centimeters (8 to 25 inches)].
Bk1--64 to 81 centimeters (25 to 32 inches); light olive brown (2.5Y 5/3) silty clay loam, light yellowish brown (2.5Y 6/3) dry; weak medium prismatic structure parting to weak fine subangular blocky; hard, friable, slightly sticky, slightly plastic; common very fine roots; common very fine pores; many fine and medium carbonate masses; 5 percent worm casts and worm holes; violently effervescent; slightly alkaline; abrupt wavy boundary. [Bk horizon thickness is 0 to 51 centimeters (0 to 20 inches)].
2Bk2--81 to 122 centimeters (32 to 48 inches); light olive brown (2.5Y 5/4) clay loam, pale yellow (2.5Y 7/3) dry; weak coarse prismatic structure; very hard, firm, moderately sticky, moderately plastic; few very fine roots; few very fine pores; common fine and medium carbonate masses; 3 percent gravel; few fine distinct olive yellow (2.5Y 6/6) redoximorphic concentrations and few fine distinct grayish brown (2.5Y 5/2) redoximorphic depletions; violently effervescent; moderately alkaline; gradual wavy boundary. [20 to 76 centimeters thick (8 to 30 inches)].
2C--122 to 152 centimeters (48 to 60 inches); light olive brown (2.5Y 5/4) clay loam, pale yellow (2.5Y 7/4) dry; massive; very hard, firm, moderately sticky, moderately plastic; few fine and medium carbonate masses; 3 percent gravel;common fine distinct olive yellow (2.5Y 6/6) redoximorphic concentrations and common fine distinct grayish brown (2.5Y 5/2) redoximorphic depletions; strongly effervescent; moderately alkaline.
TYPE LOCATION: Hamlin County, South Dakota; 727 meters (2385 feet) north and 60 meters (195 feet) east of the southwest corner of section 14, T. 114 N., R. 51 W.; USGS Dempster, S. Dak. topographic quadrangle; lat. 44 degrees 40 minutes 56.00 seconds N. and long. 96 degrees 55 minutes 29.36 seconds W., NAD 83.
RANGE IN CHARACTERISTICS: The depth to glacial till ranges from 51 to 102 centimeters (20 to 40 inches). Thickness of the mollic epipedon ranges from 41 to 76 centimeters (16 to 30 inches) and extends into the B horizon. The depth to carbonates ranges from 51 to 97 centimeters (20 to 38 inches). Some pedons have carbonates at a shallower depth due to mixing by worm activity. A stone line 3 to 8 centimeters (1 to 3 inches) in thickness is at the glacial till contact in most pedons.
The A horizon has value of 2 or 3 and 3 or 4 dry, and chroma of 1. It typically is silty clay loam, but is silt loam in some pedons. It is slightly acid to neutral.
The Bw horizon has hue of 10YR or 2.5Y, value of 2 to 4 and 3 to 5 dry, and chroma of 1 to 4. It typically is silty clay loam, but is silt loam in some pedons. It ranges from neutral to slightly alkaline.
The Bk horizon has hue of 2.5Y, value of 4 to 6 and 5 to 7 dry, and chroma of 2 to 4. It is silty clay loam or silt loam. Reaction is slightly alkaline or moderately alkaline.
The 2Bk horizon has hue of 2.5Y, value of 4 to 6 and 5 to 7 dry, and chroma of 2 to 4. Most pedons have few or common, faint to prominent redoximorphic features. Some pedons contain diagonal wedges up to 8 centimeters (3 inches) in width of sandy material. It is clay loam or loam. Reaction is slightly alkaline or moderately alkaline.
The 2C horizon has hue of 2.5Y or 5Y, value of 4 to 6 and 5 to 7 dry, and chroma of 2 to 4. Most pedons have common or many, faint to prominent redoximorphic features. Some pedons contain diagonal wedges up to 8 centimeters (3 inches) in width of sandy material. It is clay loam or loam. Reaction is slightly alkaline or moderately alkaline.
COMPETING SERIES: COMPETING SERIES: These are the Beotia, Graceland, Overly, and Waubay series. The Beotia and Overly soils are varved with thin layers of sand to clay at a depth of 102 to 152 centimeters (40 to 60 inches). Varves range from 1 mm to 10 mm in thickness. The Graceland and Waubay soils have glacial till at a depth greater than 102 centimeters (40 inches). The Waubay soils also have strata in the horizon above the glacial till. Strata ranges in texture from loam to silty clay loam and are 10 mm to 50 mm in thickness.
GEOGRAPHIC SETTING: Brookings soils are on nearly level and gently sloping footslopes and in swales on uplands. Surfaces are plane or concave, and slope gradients range from 0 to 6 percent. These soils formed in 51 to 102 centimeters (20 to 40 inches) of loess overlying glacial till. Mean annual temperature ranges from 4 to 7 degrees C (38 to 45 degrees F), and mean annual precipitation ranges from 485 to 735 millimeters (19 to 29 inches). Growing season is about 120 to 160 days; average growing season precipitation ranges from 330 to 457 millimeters (13 to 18 inches); and growing degree days are about 2500 to 3000.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Badger, Hidewood, Kranzburg, McKranz, and Vienna soils. The somewhat poorly drained Badger soils have fine textured control sections and are in deeper swales. The poorly drained Hidewood soils are in drainageways. McKranz soils have a calcic horizon within 41 centimeters (16 inches) of the surface and are along the edges of the deeper swales and drainageways. Kranzburg and Vienna soils have a mollic epipedon less than 41 centimeters (16 inches) thick and are on convex to plane slopes above the Brookings soils.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Moderately well drained. Surface runoff is low. Saturated hydraulic conductivity, measured in cm per hour, is 1.52 to 5.10 (.6 to 2.0 inches) in the upper mantle and .51 to 1.52 (.2 to .6 inches) in the underlying glacial till. Saturation occurs at depths as high as 1 meter (3 feet) during spring months in years of normal rainfall.
USE AND VEGETATION: Most of the Brookings soils are cultivated, the principal crops are: corn, soybeans, small grain, and alfalfa. Native vegetation typically is big bluestem, Indiangrass, switchgrass, sedges, and a variety of forbs.
DISTRIBUTION AND EXTENT: MLRA-102A. Northeastern South Dakota and southwestern Minnesota. Moderately extensive.
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 64 centimeters (25 inches) (Ap, A, Bw horizons); calcic horizon - the zone from about 64 to 122 centimeters (25 to 48 inches) (Bk1, 2Bk2 horizon).
The classification of the Brookings series was changed from Aquic Hapludolls to a Pachic Hapludolls.