LOCATION FORDVILLE SD+MN+NDEstablished Series
TAXONOMIC CLASS: Fine-loamy over sandy or sandy-skeletal, mixed, superactive, frigid Pachic Hapludolls
TYPICAL PEDON: Fordville loam, on a plane slope of 1 percent, in a cultivated field. When described the soil was dry throughout. (Colors are for dry soil unless otherwise stated.)
Ap--0 to 6 inches; very dark gray (10YR 3/1) loam, black (10YR 2/1) moist; weak fine granular structure; slightly hard, friable; few fine and common very fine roots; common very fine pores; neutral; abrupt smooth boundary. (6 to 14 inches thick)
Bw1--6 to 12 inches; very dark grayish brown (10YR 3/2) loam, very dark brown (10YR 2/2) moist; moderate medium prismatic structure parting to moderate medium subangular blocky structure; slightly hard, friable; common very fine roots; few very fine pores; neutral; clear wavy boundary.
Bw2--12 to 19 inches; dark grayish brown (10YR 4/2) loam, very dark grayish brown (10YR 3/2) moist; moderate medium prismatic structure parting to moderate medium subangular blocky structure; slightly hard, friable; common very fine roots; few very fine pores; neutral; clear wavy boundary.
Bw3--19 to 24 inches; brown (10YR 5/3) loam, brown (10YR 4/3) moist; moderate medium and coarse prismatic structure parting to moderate medium and coarse subangular blocky structure; slightly hard, friable; common very fine roots; few very fine pores; slightly alkaline; clear wavy boundary. (Combined thickness of the Bw horizon is 9 to 30 inches.)
Bk1--24 to 33 inches; pale yellow (2.5Y 7/4) loam, light olive brown (2.5Y 5/4) moist; moderate medium and coarse prismatic structure parting to moderate medium and moderate coarse subangular blocky structure; slightly hard, friable; few very fine roots; many very fine pores; common fine and medium carbonate masses; 28 percent calcium carbonate equivalent; strongly effervescent; moderately alkaline; gradual wavy boundary. (0 to 14 inches thick)
2Bk2--33 to 41 inches; light yellowish brown (2.5Y 6/3) very gravelly loamy sand, olive brown (2.5Y 4/3) moist; single grain; loose; common carbonate coats on the undersides of rock fragments; 13 percent calcium carbonate equivalent; 40 percent gravel; strongly effervescent; moderately alkaline; gradual wavy boundary. (5 to 15 inches thick)
2C--41 to 80 inches; pale yellow (2.5Y 7/3) very gravelly sand, light olive brown (2.5Y 5/3) moist; single grain; loose; few carbonate coats on the undersides of rock fragments; 16 percent calcium carbonate equivalent; 45 percent gravel; slightly effervescent; moderately alkaline.
TYPE LOCATION: Codington County, South Dakota; about 5 miles south and 3 miles east of Florence; about 325 feet south and 175 feet east of the northwest corner of section 6, T. 117 N., R. 53 W.; USGS Watertown West topographic quadrangle; lat 44 degrees 58 minutes 38 seconds N. and long. 97 degrees 14 minutes 56 seconds W., NAD 83.
RANGE IN CHARACTERISTICS: Thickness of the mollic epipedon ranges from 16 to 30 inches and commonly includes the Bw horizon. Depth to sand and gravel typically is about 24 to 34 inches and ranges from 20 to 40 inches.
The A horizon has value of 3 or 4 and 2 or 3 moist, and chroma of 1 moist and 1 or 2 dry, but some pedons have chroma of 2 moist below the Ap horizon. It typically is loam but silt loam is also included. It is slightly acid or neutral.
The Bw horizon has value of 3 to 5 and 2 to 4 moist, and chroma of 1 to 4. It is loam, silt loam, or clay loam averaging between 18 and 30 percent clay. It ranges from slightly acid to slightly alkaline.
The Bk horizon has hue of 10YR or 2.5Y, values of 4 to 8 and 3 to 6 moist, and chroma of 2 to 4. It typically is loam or clay loam, but in some places, is sandy clay loam, fine sandy loam, or sandy loam. The Bk horizon is slightly or moderately alkaline. Some pedons have a BC horizon.
The 2Bk and 2C horizons have hue of 10YR or 2.5Y, value of 4 to 7 and 3 to 6 moist, and chroma of 2 to 4. The less than 2 mm fraction is loamy sand, sand, or coarse sand. Coarse fragment content ranges from 15 to 50 percent. Thin strata of finer textures are in some pedons. It is slightly or moderately alkaline.
COMPETING SERIES: These are the Fordtown, Spottswood and Vang series. The Fordtown soils have saturation within depths of 3.5 feet. The Spottswood soils have redox features within depths of 40 inches and are moderately well drained. Vang soils have 50 percent or more coarse shale fragments within depths of 20 to 40 inches.
GEOGRAPHIC SETTING: Fordville soils are on outwash plains and terraces of streams that dissect the glacial till plains. Surfaces are plane to convex. Slope gradients range from 0 to 9 percent. The soil formed in loamy alluvium over stratified sand and gravel. Mean annual air temperature ranges from 38 to 45 degrees F, and mean annual precipitation ranges from 16 to 24 inches. The growing season is about 120 to 140 days; the average growing season precipitation ranges from 13 to 17 inches. The growing degree days are about 2,500 to 3,000. Elevation ranges from 1,300 to 2,000 feet above sea level.
GEOGRAPHICALLY ASSOCIATED SOILS: This is the competing Spottswood series and the Divide, Marysland, Renshaw, and Sioux soils. Spottswood, Divide, and Marysland soils are on lower and wetter parts of the outwash plains and terraces. Renshaw soils have a mollic epipedon less than 16 inches thick, are shallow to gravel, and are on slightly higher positions. Divide and Marysland soils have calcic horizons within depths of 16 inches. Sioux soils have sand and gravel at depths of less than 14 inches and are higher convex positions.
DRAINAGE AND PERMEABILITY: Well drained. Surface runoff is medium or low. Permeability is moderate in the upper mantle and very rapid in the underlying sand and gravel.
USE AND VEGETATION: When cultivated, the principal crops are corn, soybeans, small grain, and alfalfa. Native vegetation consists mainly of big bluestem, little bluestem, needlegrass, western wheatgrass, blue grama, sideoats grama, upland sedges, and forbs.
DISTRIBUTION AND EXTENT: MLRA 102A. Northeastern South Dakota, eastern North Dakota, and western Minnesota. This series is extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Rock County, Minnesota, 1945.
REMARKS: Diagnostic horizons and features recognized in this pedon include: mollic epipedon - the zone from the surface of the soil to a depth of about 19 inches (Ap, Bw1, Bw2, horizons); cambic horizon - the zone from 19 to 41 inches (Bw3, Bk1 and 2Bk2 horizons). Fordville soils have a udic moisture regime and a frigid temperature regime.
ADDITIONAL DATA: Laboratory sample number: S00-SD029-004.