LOCATION ALWILDA SDEstablished Series
TAXONOMIC CLASS: Sandy, mixed, mesic Typic Haplustolls
TYPICAL PEDON: Alwilda fine sandy loam - with a plane slope of 1 percent in a cultivated field. When described, the soil was moist throughout. (Colors are for dry soil unless otherwise stated.)
Ap--0 to 8 inches; very dark gray (10YR 3/1) fine sandy loam, black (10YR 2/1) moist; weak fine granular structure; slightly hard, friable; slightly acid; abrupt smooth boundary.
A--8 to 12 inches; very dark gray (10YR 3/1) fine sandy loam, black (10YR 2/1) moist; weak coarse and medium subangular blocky structure parting to weak fine granular; slightly hard, very friable; slightly acid; clear smooth boundary. (Combined thickness of the A horizon is 6 to 15 inches)
Bw1--12 to 18 inches; dark grayish brown (10YR 4/2) fine sandy loam, very dark brown (10YR 2/2) moist; weak medium prismatic structure parting to weak medium and fine subangular blocky; slightly hard, very friable; common tongues of black (10YR 2/1) moist; neutral; clear smooth boundary.
Bw2--18 to 24 inches; grayish brown (10YR 5/2) fine sandy loam, very dark grayish brown (10YR 3/2) moist; weak medium prismatic structure parting to weak medium subangular blocky; slightly hard, very friable; common tongues of black (10YR 2/1) moist; neutral; clear smooth boundary. (Combined Bw horizons is 10 to 20 inches thick.)
BC--24 to 29 inches; grayish brown (10YR 5/2) loamy fine sand, very dark grayish brown (10YR 3/2) moist; weak medium subangular blocky structure; slightly hard, very friable; few tongues of black (10YR 2/1) moist; neutral; clear smooth boundary. (0 to 10 inches thick)
2C1--29 to 46 inches; multicolored gravelly sand; single grain; loose; 25 percent gravel by volume; carbonates coat undersides of pebbles; slight effervescence; slightly mildly alkaline; gradual wavy boundary.
2C2--46 to 60 inches; multicolored gravelly sand; single grain; loose; 15 percent gravel by volume; carbonates coat undersides of pebbles; strong effervescence; slightly alkaline.
TYPE LOCATION: Sanborn County, South Dakota; about 4 miles east and 4 miles north of Woonsocket; 1,250 feet west and 480 feet north of the southeast corner of sec. 31, T. 108 N., R. 61 W.
RANGE IN CHARACTERISTICS: The depth to carbonates and the underlying gravelly sand typically ranges from 20 to 30 inches, but can be as deep as 40 inches. The mollic epipedon is 15 to 20 inches thick. The soil has colors of the mollic epipedon to depths greater than 20 inches but it has less than 0.6 percent organic carbon. The control section averages between 5 and 10 percent clay and contains less than 35 percent gravel by volume.
The A horizon has hue of 10YR, value of 3 or 4 and 2 or 3 moist, and chroma of 1 or 2. It is fine sandy loam, sandy loam or loam and ranges from medium acid to neutral.
The Bw horizon has hue of 10YR, value of 3 to 5 and 2 or 3 moist, and chroma of 1 to 3. It is fine sandy loam or sandy loam. It is slightly acid or neutral.
The BC horizon has hue of 10YR or 2.5Y, value of 4 to 6 and 3 to 5 moist, and chroma of 2 to 4 dry or moist. It is loamy fine sand or loamy sand and ranges from slightly acid to slightly alkaline.
The 2C horizon is multicolored layers of calcareous sand and gravel (15 to 45 percent gravel by volume). It is gravelly sand, gravelly loamy sand, very gravelly sand, and very gravelly loamy sand but some pedons are loamy fine sand or loamy sand in the upper 4 to 10 inches and some pedons have thin lenses of silt loam, very fine sandy loam or coarse sand. It is slightly or moderately alkaline and contains carbonates as coatings on undersides of the gravel and sand.
COMPETING SERIES: There are no other series in this family.
GEOGRAPHIC SETTING: These nearly level to gently sloping soils are on terraces and glacial outwash plains. Surfaces are plane or concave and slope gradients range from 0 to 6 percent. The soils formed in loamy outwash sediments overlying gravelly sand. Mean annual temperature ranges from 45 to 52 degrees F, and mean annual precipitation ranges from 17 to 26 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Blendon, Carthage, Doger, Enet, Fedora, and Woonsocket soils. Blendon, Carthage, and Doger soils are in similar positions. Blendon and Carthage soils have a coarse-loamy control section. In addition, Blendon soils have a mollic epipedon greater than 20 inches thick. Doger soils have less than 15 percent gravel in the underlying material. Enet soils are fine-loamy over sandy or sandy-skeletal and are in similar positions. Fedora and Woonsocket soils are in lower parts of the landscape and are more moist. In addition, Fedora soils have a calcic horizon and are wetter and Woonsocket soils have a fine-loamy control section.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained. Runoff is low or medium. Permeability is moderately rapid in the solum and rapid in the underlying material.
USE AND VEGETATION: The soils are cultivated and the principal crops are small grain, grain sorghum, corn, and alfalfa or they are in tame pasture. Native vegetation is mainly little bluestem, prairie sandreed, blue grama, and needleandthread.
DISTRIBUTION AND EXTENT: East-central South Dakota. The series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Sanborn County, South Dakota, November, 1978.
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 12 inches (Ap and A horizons).