LOCATION DEGREY SDEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Typic Natrustolls
TYPICAL PEDON: DeGrey silt loam - on a slope of 1 percent in native grass. (Colors are for dry soil unless otherwise stated.)
A--0 to 4 inches; dark gray (10YR 4/1) silt loam, very dark gray (10YR 3/1) moist; weak medium and fine granular structure; soft, friable; neutral; clear smooth boundary. (3 to 7 inches thick)
E--4 to 6 inches; gray (10YR 5/1) silt loam, very dark gray (10YR 3/1) moist; weak thin platy structure; soft, very friable; neutral; abrupt smooth boundary. (1 to 4 inches thick)
Btn1--6 to 9 inches; dark grayish brown (10YR 4/2) silty clay, very dark grayish brown (10YR 3/2) moist, moderate medium columnar structure parting to strong medium and fine blocky; very hard, very firm, sticky and plastic; moderately alkaline; clear smooth boundary.
Btn2--9 to 14 inches; dark grayish brown (10YR 4/2) silty clay, very dark grayish brown (10YR 3/2) moist; moderate medium prismatic structure parting to strong medium and fine blocky; very hard, very firm, sticky and plastic; few fine clay films on faces of peds; moderately alkaline; clear smooth boundary. (Combined Bt horizons is 6 to 13 inches thick.)
Btk--14 to 19 inches; grayish brown (10YR 5/2) silty clay, dark grayish brown (10YR 4/2) moist; moderate medium prismatic structure parting to moderate coarse subangular blocky; very hard, very firm, sticky and plastic; few fine clay films on vertical faces of peds; few fine masses and threads of carbonate accumulations; strong effervescence; moderately alkaline; clear wavy boundary. (0 to 10 inches thick)
Bk1--19 to 36 inches; light brownish gray (2.5Y 6/2) silty clay loam, light olive brown (2.5Y 5/4) moist; weak fine subangular blocky structure; hard, firm, slightly sticky and slightly plastic; few fine accumulations of carbonate; strong effervescence; moderately alkaline; clear wavy boundary. (5 to 30 inches thick)
2Bk2--36 to 47 inches; light brownish gray (2.5Y 6/2) clay loam, grayish brown (2.5YR 5/2) moist; weak medium and coarse subangular blocky structure; hard, firm, sticky and plastic; few fine stains of yellowish red (5YR 5/8); few fine pebbles up to 1/2 inch in diameter; common medium accumulations of carbonate; strong effervescence; moderately alkaline; gradual wavy boundary. (0 to 18 inches thick)
2C--47 to 60 inches; light brownish gray (2.5Y 6/2) clay loam, dark grayish brown (2.5Y 4/2) moist; massive; very hard, firm, sticky and plastic; few fine and medium stains of yellowish red (5YR 5/8); 5 percent by volume fine weathered shale fragments; few fine crystals of gypsum; strong effervescence; moderately alkaline.
TYPE LOCATION: Sully County, South Dakota; about 2 miles south and 3 miles east of Okoboji; 1118 feet north and 182 feet west of the center of sec. 3, T. 113 N., R. 79 W.
RANGE IN CHARACTERISTICS: Depth to carbonate ranges from 10 to 24 inches and typically is about 14 to 16 inches. Thickness of the mollic epipedon ranges from 7 to 20 inches. The natric horizon has an SAR and ESP of 10 to 20. The thickness of the silty material ranges from 20 to more than 40 inches over glacial till. This silty material contains less than 15 percent fine sand or coarser.
The A horizon has value of 4 or 5 and 2 or 3 moist, and chroma of 1 or 2. It is slightly acid or neutral.
The E horizon has value of 5 to 7 and 3 or 4 moist, and chroma of 1 to 3. It is slightly acid or neutral. In cultivated areas the A and E horizons are mixed producing a gray cast in plowed fields.
The Btn horizon has hue of 10YR or 2.5Y, value of 4 or 5 and 3 or 4 moist, and chroma of 1 or 2. The Bt horizon commonly is silty clay, and less commonly silty clay loam, averaging between 35 and 50 percent clay. It ranges from neutral to moderately alkaline.
The Bk horizon has hue of 2.5Y or 10YR, values of 5 to 7 and 4 or 5 moist, and chroma of 2 to 4. It is silty clay loam or silty clay. It is slightly or moderately alkaline. It has few to many, fine or medium accumulations of carbonate. When present the 2Bk horizon has colors and textures of the 2C horizon.
The 2C horizon has hue of 2.5Y or 5Y, value of 5 to 7 and 4 to 6 moist, and chroma of 2 to 4 dry or moist. It is loam or clay loam. It is moderately alkaline or strongly alkaline. It contains 1 to 10 percent coarse fragments. Visible salts typically are in the 2C horizon, but are in horizons with accumulations of carbonates in some pedons.
COMPETING SERIES: These are the Cavo, Dudley, Dwight, Farmsworth, Mosher, and Wood River series. Cavo, Dudley, Mosher, and Wood River soils contain more than 15 percent fine sand or coarser in the series control section. In addition, Dudley soils have mollic epipedons more than 20 inches thick. Dwight soils have a wetter soil moisture control section, warmer soil temperatures and have mean annual temperatures of more than 50 degrees F, and do not have 2C horizons. Farmsworth soils have low chroma mottles in underlying material due to wetness.
GEOGRAPHIC SETTING: DeGrey soils are on silty mantled glacial till plains with plane to concave surfaces. Slopes commonly are less than 2 percent but range from 0 to 6 percent. The soils formed in 20 to 40 inches or more of silty materials over glacial till. Mean annual temperature ranges from 45 to 48 degrees F, and mean annual precipitation ranges from 17 to 21 inches. Growing season is about 130 to 155 days; growing season precipitation ranges from 13 to 17 inches; and growing degree days is about 2800 to 3200.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Agar, Eakin, Highmore, Hoven, Onita, and Walke soils. The Agar, Eakin, and Highmore soils do not have natric horizons, are fine-silty in higher landscapes. Hoven soils are wetter and in depressions. Onita soils have thicker mollic epipedons, do not have natric horizons, and are in swales. Walke soils do not have columnar structure in the argillic horizon and have tonguing of an albic horizon into the argillic horizon. Walke soils are intermingled with the DeGrey soils in similar landscapes.
DRAINAGE AND PERMEABILITY: Moderately well drained. Runoff is low on slopes of 2 percent or less and medium on slopes of 2 to 6 percent. Permeability is slow or very slow. A water table may be within 3.5 feet of the surface for short periods in the spring of the year.
USE AND VEGETATION: Native range and cultivated crops. Native vegetation is mainly western wheatgrass, green needlegrass, blue grama, buffalograss, and threadleaf sedge. Principal cultivated crops are corn, small grain, and alfalfa.
DISTRIBUTION AND EXTENT: Central and south-central South Dakota. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Hughes County, South Dakota, 1971.
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 14 inches (A, E, Btn1, Btn2 horizons); argillic (Natric) horizon - the zone from about 6 to 19 inches (Btn1, Btn2, Btnk horizon).