LOCATION SINAI SD+MN NDEstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Typic Hapluderts
TYPICAL PEDON: Sinai silty clay - on a nearly level slope in a cultivated field. When described the soil was moist throughout. (Colors are for dry soil unless otherwise stated.)
Ap--0 to 7 inches; very dark gray (10YR 3/1) silty clay, black (10YR 2/1) moist; weak medium subangular blocky structure parting to moderate medium granular; slightly hard, friable, sticky and plastic; few fine roots; slightly acid; abrupt smooth boundary.
A--7 to 12 inches; very dark gray (10YR 3/1) silty clay, black (10YR 2/1) moist; moderate medium subangular blocky structure parting to moderate medium granular; very hard, firm, sticky and plastic; few fine roots; slightly acid; cracks 1/2 inch to 1 inch wide; clear smooth boundary (Combined thickness of the A horizon is 8 to 17 inches.)
Bss--12 to 23 inches; dark gray (10YR 4/1) silty clay, very dark grayish brown (10YR 3/2) moist; moderate medium prismatic structure parting to moderate medium subangular blocky; hard, firm, very sticky and very plastic; few fine roots; surfaces of peds are shiny; tongues of very dark gray (10YR 3/1) moist, 1/8 inch to over 2 inches thick are common; few intersecting slickensides;; neutral; clear wavy boundary. (7 to 16 inches thick)
Bkss1--23 to 33 inches; light brownish gray (2.5Y 6/2) silty clay, dark grayish brown (2.5Y 4/2) moist; moderate medium prismatic structure parting to moderate medium subangular blocky; hard, firm, sticky and plastic; tongues of very dark gray (10YR 3/1) moist, 1/8 inch to over 2 inches thick; few intersecting slickensides; strong effervescence; moderately alkaline; clear wavy boundary.
Bkss2--33 to 42 inches; light gray (2.5Y 7/2), silty clay, grayish brown (2.5Y 5/2) moist; few medium prominent yellowish brown (10YR 5/6) redox concentrations moist; moderate medium prismatic structure; very hard, firm, sticky and plastic; few intersecting slickensides; common fine and medium accumulations of calcium carbonate; strong effervescence; moderately alkaline; gradual wavy boundary. (combined thickness of the Bk horizon is 8 to 30 inches)
C--42 to 60 inches; light brownish gray (2.5Y 6/2) silty clay, dark grayish brown (2.5Y 4/2) moist; few
coarse prominent yellowish brown (10YR 5/6) redox concentrations; massive; very hard, firm, sticky and plastic; few fine nests of gypsum; slight effervescence; moderately alkaline.
TYPE LOCATION: Day County, South Dakota; 740 feet west and 310 feet south of the northeast corner, Sec. 4, T. 124 N., R. 55 W.
RANGE IN CHARACTERISTICS: Depth to free calcium carbonate ranges from about 17 to 35 inches. Thickness of the mollic epipedon ranges from 16 to 25 inches. Tonguing of A horizon material occurs below the Ap or A horizon above depths of 35 inches. The tongues of soil material extend into the C horizons in some pedons. The particle size control section contains 45 to 60 percent clay. When the soil is dry, cracks 1/8 inch to 2 inches wide and several feet long extend downward through the solum.
The A horizon has value of 3 or 4 and 2 or 3 moist, and chroma of 1 or 2. It typically is silty clay, but is silty clay loam or clay in some pedons. It is slightly acid or neutral.
The Bss horizon has hue of 10YR or 2.5Y, value of 3 to 6 and 2 to 4 moist, and chroma of 1 to 3. It is silty clay or clay. Some pedons have mottles inherent to the parent material. Intersecting slickensides are few to common. It is neutral or slightly alkaline.
The Bkss and C horizons have hue of 10YR, 2.5Y, or 5Y; value of 4 to 7 and 3 to 6 moist and chroma of 1 to 6. It is silty clay or clay. Intersecting slickensides are few to common. The C horizon in most pedons is stratified with layers of silty clay, silty clay loam, clay loam, and silt loam. It is slightly alkaline or moderately alkaline. Most pedons have mottles inherent to the parent material in the Bk and C horizons.
COMPETING SERIES: These are the Hattie and Wahpeton series. Hattie soils contain 2 to 8 percent rock fragments in the series control section. Wahpeton soils typically have buried horizons and an irregular decrease in organic carbon.
GEOGRAPHIC SETTING: Sinai soils are nearly level to moderately sloping on uplands having plane and convex surfaces. Slope gradients typically are less than 6 percent, but range from 0 to 9 percent. They are mostly circular in shape, are typically surrounded by shallow depressions or moats, and are in high parts of the landscape. The soils formed in clayey glaciolacustrine sediments of ice-walled lakes. Mean annual air temperature ranges from 39 to 48 degrees F, and mean annual precipitation ranges from 16 to 27 inches. Growing season is about 125 to 130 days; average growing season precipitation from 13 to 22 inches; and growing degree days are about 2500 to 3000.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Barnes, Buse, Forman, Kranzburg, Nutley, Peever, Poinsett, and Tonka soils. Nutley soils are on similar landscapes and have a mollic epipedon less than 16 inches thick. Sinai soils are on slightly higher positions in the landscape than the Barnes, Forman, Kranzburg, Poinsett, and Peever soils. Buse soils are on plane to convex slopes below the Sinai soils. The Barnes, Buse, and Forman soils contain less than 35 percent clay in the control section. The Kranzburg, Poinsett, and Peever soils have a mollic epipedon less than 16 inches thick. In addition, the Kranzburg and Poinsett soils have less than 35 percent clay in the control section. The Peever soils have an argillic horizon. Tonka soils have an albic horizon and are in depressions.
DRAINAGE AND PERMEABILITY: Moderately well drained and well drained. Surface runoff is low to very high. Permeability is slow or very slow. An apparent seasonal high water table is at a depth of 3.5 to 6 feet at some time from March to June for the moderately well drained phase.
USE AND VEGETATION: Most areas are used to grow corn, small grains, and alfalfa. Native grasses include little bluestem, western wheatgrass, big bluestem, green needlegrass, and sideoats grama.
DISTRIBUTION AND EXTENT: Northeastern and east-central South Dakota and adjacent parts of North Dakota and Minnesota. It is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Day County, South Dakota, 1952.
REMARKS: Diagnostic horizons and features recognized in this pedon are: mollic epipedon - the zone from the surface of the soil to a depth of 23 inches. (Ap, A, and Bss horizons)