LOCATION EVRIDGE SD+NDEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, frigid Typic Natrustolls
TYPICAL PEDON: Evridge fine sandy loam-on a 1 percent slope in native grass. (Colors are for dry soil unless otherwise stated).
A1--0 to 7 inches; dark grayish brown (10YR 4/2) fine sandy loam, very dark grayish brown (10YR 3/2) moist; weak coarse subangular blocky structure; soft, very friable; common fine and medium roots; slightly acid; gradual wavy boundary.
A2--7 to 18 inches; dark grayish brown (10YR 4/2) loamy fine sand, very dark grayish brown (10YR 3/2) moist; weak coarse subangular blocky structure parting to weak fine granular; soft, very friable; few fine and medium roots; neutral; clear wavy boundary. (Combined A horizons 10 to 25 inches thick)
E--18 to 23 inches; grayish brown (2.5Y 5/2) loamy fine sand, dark grayish brown (2.5Y 4/2)moist; weak coarse subangular blocky structure parting to weak coarse platy; soft, very friable; few fine and medium roots; slightly alkaline; clear wavy boundary. (3 to 8 inches thick)
Btn--23 to 28 inches; grayish brown (2.5Y 5/2) fine sandy loam, dark grayish brown (2.5Y 4/2) moist; coats on faces of peds; moderate coarse columnar structure parting to weak coarse subangular blocky; slightly hard, friable; moderately alkaline; abrupt wavy boundary. (4 to 9 inches thick)
Bk--28 to 38 inches; light olive gray (5Y 6/2) fine sandy loam, grayish brown (2.5Y 5/2) moist; weak fine subangular blocky structure; slightly hard, friable; 70 percent weathered fragments of sandstone, easily crushed; common fine and medium accumulations of carbonates; strong effervescence; strongly alkaline; gradual wavy boundary. (0 to 20 inches)
Cr--38 to 60 inches; light olive gray (5Y 6/2) sandstone, olive gray (5Y 5/2) moist; easily crushed; slight effervescence; strongly alkaline.
TYPE LOCATION: Corson County, South Dakota; 1950 feet east and 100 feet north of the southwest corner of sec. 12, T. 18 N., R. 19 E.
RANGE IN CHARACTERISTICS: The depth to soft bedrock ranges from 20 to 40 inches. Thickness of the mollic epipedons is 7 to 16 inches. Where moist colors darker than 3.5 extend below depths of 16 inches, organic carbon is less than .6 percent. Depth to free carbonates ranges from 20 to 40 inches.
The A horizon has hue of 10YR or 2.5Y, value of 4 or 5 and 2 or 3 moist, and chroma of 2 or 3. The A horizon typically is fine sandy loam, but some pedons are loam, sandy loam, or loamy fine sand. It is slightly acid or neutral.
The E horizon has hue of 10YR or 2.5Y, value of 5 to 7 and 4 to 6 moist, and chroma of 2 or 3. It is fine sandy loam or loamy fine sand. It ranges from neutral to moderately alkaline.
The Btn horizon has hue of 10YR or 2.5Y, value of 5 or 6 and 4 or 5 moist, and chroma of 2 or 3. It typically is fine sandy loam, but some pedons are very fine sandy loam, sandy loam, or loam. It has moderate to strong medium to very coarse columnar structure. Carbonates are in the lower B horizon in some pedons. The SAR is 10 to 20. It ranges from moderately to strongly alkaline. Some pedons have loamy sand and loamy fine sand BC horizons.
The Bk horizon has hue of 10YR, 5Y, or 2.5Y, value of 5 to 7 and 4 to 6 moist, and chroma of 2 or 3. It is fine sandy loam or sandy loam and is 60 to 80 percent by volume soft weathered rock fragments. It has few to common accumulations of carbonates. It is moderately or strongly alkaline. Some pedons have salts below a depth of 20 inches.
Some pedons have a C horizon with color and texture of the B or BC horizons.
The Cr horizon has hue of 10YR, 2.5Y, or 5Y, value of 3 to 8 and 2 to 7 moist, and chroma of 1 to 4. It is soft sandstone. Some pedons may have thin layers of siltstone or shale. It is moderately to strongly alkaline. The upper part typically contains carbonates.
COMPETING SERIES: These are the Desart, Ekalaka, and Portal series. The Desart, Ekalaka, and Portal soils do not have bedrock within a depth of 40 inches.
GEOGRAPHIC SETTING: Evridge soils are on nearly level to strongly sloping uplands and ridges. Surfaces are plane or concave and slope gradients range from 0 to 15 percent. Evridge soils formed in loamy material derived from soft sandstone and shale. Mean annual air temperature ranges from 39 to 45 degrees F, and mean annual precipitation ranges from 13 to 16 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Ekalaka soils and the Bullock, Parchin, Parshall, Tally, Rhoades and Vebar soils. The Ekalaka soil is on similar landscape positions and is in complex with the Evridge soils in some areas. Bullock and Parchin soils do not have a mollic epipedon and are in the fine-loamy family. Rhoades soils are fine textured. The Bullock, Parchin, and Rhoades soils are on lower parts of the landscape. The Parshall, Tally, and Vebar soils do not have natric horizons. Parshall soils are in swales, Tally soils are on terraces, and Vebar soils are on nearby uplands.
DRAINAGE AND PERMEABILITY: Well drained. Runoff is slow on slopes of 0 to 6 percent and medium of 6 to 15 percent. Permeability is moderately rapid above the Bt horizon and slow through it.
USE AND VEGETATION: Most areas are in range and used for grazing. Native vegetation is mainly prairie sandreed, little bluestem, needleandthread, big bluestem, western wheatgrass, blue grama, and sedges.
DISTRIBUTION AND EXTENT: Northwestern South Dakota. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Corson County, South Dakota, 1985.