LOCATION OAK LAKE SD+MNEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, frigid Haplic Vermudolls
TYPICAL PEDON: Oak Lake silty clay loam on a 1 percent slope in a cropped field. (Colors are for moist soil unless otherwise indicated.)
Ap--0 to 10 inches; black (10YR 2/1) silty clay loam, very dark gray (10YR 3/1) dry; weak fine subangular blocky structure parting to weak fine granular; friable; 30 percent worm casts and worm holes; many fine and very fine roots; neutral; abrupt smooth boundary. (6 to 12 inches thick)
A--10 to 23 inches; black (10YR 2/1) silty clay loam, very dark gray (10YR 3/1) dry; weak fine subangular blocky structure parting to weak fine granular; friable; 50 percent worm casts and worm holes; common fine and very fine roots; neutral; gradual wavy boundary. (0 to 15 inches thick)
AB--23 to 29 inches; black (10YR 2/1) and olive brown (2.5Y 4/3) silty clay loam; very dark gray (10YR 3/1) and brown (10YR 5/3) dry; weak fine prismatic structure parting to moderate fine subangular blocky; friable; 30 percent worm casts and worm holes; few fine and very fine roots; neutral; gradual wavy boundary. (4 to 12 inches thick)
Bw--29 to 43 inches; olive brown (2.5Y 4/3) silty clay loam; weak medium prismatic structure parting to weak medium subangular blocky; friable; few worm casts and worm holes; few very fine roots; common medium distinct gray (2.5Y 5/1) redox depletions and common medium distinct yellowish brown (10YR 5/6) redox concentrations; neutral; clear smooth boundary. (5 to 20 inches thick)
2Bk--43 to 69 inches; olive brown (2.5Y 4/4) clay loam; weak coarse prismatic structure parting to weak coarse subangular blocky; firm; few worm casts and worm holes; few fine roots; about 4 percent gravel; common medium distinct gray (2.5Y 5/1) redox depletions and few fine distinct yellowish brown (10YR 5/6) redox concentrations; common fine accumulations of calcium carbonate; violently effervescent; moderately alkaline; gradual smooth boundary. (12 to 30 inches thick)
2C--69 to 80 inches; olive brown (2.5Y 4/4) clay loam; massive; firm; about 4 percent gravel; common medium distinct gray (2.5Y 5/1) redox depletions and few fine distinct yellowish brown (10YR 5/6) redox concentrations; strongly effervescent; moderately alkaline.
TYPE LOCATION: Brookings County, South Dakota; about 1 mile west and 2 miles south of Astoria, South Dakota; 682 feet south and 899 feet west of the northeast corner of sec. 10, T. 112 N., R. 48W. USGS Astoria quadrangle, latitude 44 degrees 31 minutes 35.3 seconds N., longitude 96 degrees 34 minutes 6.8 seconds W., NAD 83.
RANGE IN CHARACTERISTICS: Depth to free calcium carbonate is typically 20 to 40 inches. Thickness of the mollic epipedon is 16 to 30 inches. The thickness of the silty mantle is typically 30 to 50 inches. The control section contains about 25 to 35 percent clay and less than 15 percent fine sand or coarser. The AB horizon consists mostly of worm casts and filled worm holes. The mollic epipedon, below the Ap horizon, has at least 50 percent by volume of worm casts, worm holes and worm filled holes and the transition to the underlying material has at least 25 percent worm casts, worm holes and worm filled holes.
The A horizon has hue of 10YR or 2.5Y, value of 2 or 3, and chroma of 1. The A horizon is silty clay loam, or silt loam and is neutral or slightly acid. The AB horizon has colors and textures of the A and Bw horizons.
The Bw horizon has hue of 10YR or 2.5Y, value of 3 to 5 , and chroma of 2 to 4. It is silty clay loam or silt loam, and is neutral or slightly alkaline. In some places a sandy loam transitional layer is between the Bw and 2Bk horizons.
The 2Bk horizon has hue of 10YR or 2.5Y, value of 4 to 6, and chroma of 2 to 4. It is loam or clay loam. It has few or common, fine or medium accumulations of carbonate.
The 2C horizon has hue of 2.5Y or 5Y, value of 4 to 6, and chroma of 2 to 4. It is loam or clay loam. It has few or common, faint to prominent mottles. The 2Bk and 2C horizons are slightly alkaline or moderately alkaline.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Oak Lake soils are on nearly level, plain to slightly concave slopes on ground moraines. Slope gradients range from 0 to 3 percent. The Oak Lake soils formed in loamy glacial till which is overlain by a mantle of silty material. Mean annual temperature ranges from 38 to 45 degrees F. and mean annual precipitation ranges from 19 to 23 inches. Annual frost free days are 120 to 140. Elevation ranges from 890 to 1950 feet.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Parnell, Singsaas and Winger soils. Parnell soils contain more than 35 percent clay in the particle size conrol section, have soil saturation to the surface and are in depressions. Singsaas soils formed in a thinner silt mantle and are on higher parts of the landscape. Winger soils are calcareous, have a wetter soil moisture control section and are in drainageways, rims of depressions and lower lying flats.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Moderately well drained. Surface runoff is low. Saturated hydraulic conductivity is moderately slow. The apparent seasonal high saturation is at a depth of 20 to 40 inches at some time during the months of March to May in normal years.
USE AND VEGETATION: Most areas of Oak Lake soils are cultivated. The main crops are corn, soybeans wheat and alfalfa. Native vegetation is tall grass prairie.
DISTRIBUTION AND EXTENT: MLRA-102A. Northeastern South Dakota and southwestern Minnesota. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Lincoln County, Minnesota, 2006.
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 29 inches (Ap, A and AB horizons); cambic horizon - the zone from about 29 to 69 inches (Bw and Bk horizons). Calcic horizon - the zone from about 43 to 69 inches (2Bk horizon).
The Oak Lake series was originally established for this same concept but was later combined with Singsaas and made inactive in January, 1978. With the correlation of Lincoln County, Minnesota, the Oak Lake series was once again recognized as different then the Singsaas series by being down drainage.