LOCATION OLDHAM SD+MNEstablished Series
TAXONOMIC CLASS: Fine, smectitic, calcareous, frigid Cumulic Vertic Endoaquolls
TYPICAL PEDON: Oldham silty clay loam - on a slope of less than 1 percent in a cultivated field. When described the soil was moist throughout. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 23 centimeters (0 to 9 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; slightly hard, friable, slightly sticky and slightly plastic; few snail shells; common very fine roots; few very fine pores; slight effervescence; slightly alkaline (pH 7.4); abrupt smooth boundary. [The thickness of the A horizon is 20 to 61 centimeters (8 to 24 inches).]
Bg--23 to 48 centimeters (9 to 19 inches); very dark gray (5Y 3/1) silty clay, gray (5Y 5/1) dry; weak fine and medium subangular blocky structure; very hard, firm, sticky and plastic; few very fine roots; few very fine pores; strong effervescence; moderately alkaline (pH 8.0); gradual wavy boundary. [The thickness of the Bg horizon is 0 to 38 centimeters (0 to 15 inches).]
Bkg--48 to 79 centimeters (19 to 31 inches); very dark gray (5Y 3/1) silty clay, gray (5Y 5/1) dry; weak coarse prismatic structure parting to weak fine and medium subangular blocky; very hard, firm, sticky and plastic; few very fine roots; few very fine pores; common medium and coarse accumulations of calcium carbonate; strong effervescence; moderately alkaline (pH 8.0); gradual irregular boundary. [The thickness of the Bg horizon is 0 to 38 centimeters (0 to 15 inches).]
Bkgy--79 to 102 centimeters (31 to 40 inches); very dark gray (5Y 3/1) silty clay, gray (5Y 5/1) dry; few fine prominent strong brown (7.5YR 5/8) redoximorphic concentrations; weak fine and medium subangular blocky structure; very hard, firm, sticky and plastic; few very fine roots; few very fine pores; common fine and medium masses of calcium carbonate; common fine crystals of gypsum and other salts; strong effervescence; moderately alkaline (pH 8.0); gradual irregular boundary. [The thickness of the Bg horizon is 0 to 38 centimeters (0 to 15 inches).]
Cg1--102 to 152 centimeters (40 to 60 inches); olive gray (5Y 5/2) silt loam, light gray (5Y 7/2) dry; many fine and medium prominent strong brown (7.5YR 5/8) redoximorphic concentrations; massive; very hard, firm, slightly sticky and slightly plastic; common fine dark brown (7.5YR 3/2) concretions of manganese; strong effervescence; moderately alkaline (pH 8.0); gradual wavy boundary.
Cg2--152 to 183 centimeters (60 to 72 inches); olive gray (5Y 5/2) silt loam, light olive gray (5Y 6/2) moist; common fine and medium prominent yellowish brown (10YR 5/6) redoximorphic concentrations; massive; very hard, firm, slightly sticky and slightly plastic; common fine dark brown (7.5YR 3/2) concretions of manganese; strong effervescence; moderately alkaline (pH 8.0); gradual wavy boundary.
Cg3--183 to 203 centimeters (72 to 80 inches); olive gray (5Y 5/2) silty clay loam, light olive gray (5Y 6/2) moist; common fine and medium prominent yellowish brown (10YR 5/6) redoximorphic concentrations; massive; very hard, firm, slightly sticky and slightly plastic; few fine dark brown (7.5YR 3/2) concretions of manganese; strong effervescence; moderately alkaline (pH 8.0).
TYPE LOCATION: Brookings County, South Dakota; about 9 miles west and 4 miles south of Volga; 137 meters (450 feet) north and 320 meters (1050 feet) west of the southeast corner sec. 6, T. 109 N., R. 52 W. USGS LAKE SINAI, S. DAK. topographical quadrangle; latitude 44 degrees 16 minutes 10.3 seconds N. and longitude 97 degrees 06 minutes 46.8 seconds W., NAD 83
RANGE IN CHARACTERISTICS: Depth to free calcium carbonate ranges from 0 to 25 centimeters (0 to 10 inches). The particle size control section is silty clay loam or silty clay with an estimated clay content of 35 to 45 percent and less than 15 percent fine or coarser sand. Thickness of the mollic epipedon ranges from 61 to 152 centimeters (24 to 60 inches).
The Ap horizon is neutral or has hue of 10YR, 2.5Y, or 5Y; value of 2 or 3 and 3 or 4 dry; and chroma of 1 or less. It is silty clay loam or silty clay. It is neutral or slightly alkaline.
The Bg horizon is neutral or has hue of 10YR, 2.5Y, or 5Y; value of 2 or 3 and 3 to 5 dry; and chroma of 1 or less. It is silty clay loam or silty clay. It is slightly alkaline or moderately alkaline.
The Bkg and Bkgy horizons have hue of 10YR, 2.5Y, or 5Y; value of 2 to 5 and 3 to 7 dry; and chroma of 2 or less. They are silt loam, silty clay loam or silty clay. Silt loam is restricted to below depths of 102 centimeters (40 inches). They are slightly alkaline or moderately alkaline. Some pedons do not have a Bkg horizon. Typically the contain few to many accumulations of gypsum and other salts, or calcium carbonate.
Some pedons have a BC horizon.
The Cg horizon has hue of 2.5Y or 5Y, value of 3 to 5 and 4 to 7 dry, and chroma of 1 or 2. Few to many, faint to prominent redoximorphic features are in the lower part of the Bkg and Cg horizons. The Cg horizon is silty clay loam, silt loam, clay loam, or silty clay. It is slightly alkaline or moderately alkaline. Some pedons have a 2Cg horizon with glacial till between depths of 102 and 203 centimeters (40 and 80 inches).
COMPETING SERIES: This is the Southam series. Southam soils have saturation to the surface for 12 months.
GEOGRAPHIC SETTING: The Oldham soils are mainly in flat upland depressions and basins of shallow lakes and ponds having plane or slightly concave surfaces. Slopes gradients range from 0 to 2 percent. They formed in local clayey alluvium. Mean annual air 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. Elevation ranges from 305 to 649 meters (1000 to 2130 feet).
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Southam soils and the Parnell, Poinsett, and Waubay soils. Parnell and Southam soils are in similar positions in the landscape as the Oldham soils. The Parnell soils are leached of carbonate to a depth of more than 64 centimeters (25 inches). The Poinsett and Waubay soils are fine-silty and are on adjacent uplands.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Very poorly drained. Runoff is negligible. Saturated hydraulic conductivity is .15 to 1.5 centimeters (.06 to .6 inches) per hour. Seasonal high saturation occurs at depths of 0 to 30 centimeters (0 to 1 foot) and typically occurs from October through June in normal years. The upper 15 cm is not saturated for at least one month during the months of July to September. Most areas of Oldham soils have some type of artificial drainage.
USE AND VEGETATION: Native hay and pasture, and where drained, cultivated to corn, soybeans, and small grains. Native grasses are prairie cordgrass and a variety of wetland sedges.
DISTRIBUTION AND EXTENT: MLRA-102A. Northeastern South Dakota and western Minnesota. The series 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: cumulic epipedon - the zone from the surface of the soil to a depth of about 102 centimeters (40 inches) (Ap, Bg, Bkg, Bkgy horizons); Vertic features - a linear extensibility of more than 6 cm in the upper 100 cm.
The previous classification of this series was fine, smectitic, calcareous, frigid Cumulic Vertic Epiaquolls. However, there was no data to support a perched saturation on this soil.
This soil competes with the Southam series based only on depth to saturation. Additional studies are needed in the future to see if both series are needed, or if ponded and drained phases of one of these series would be appropriate.