LOCATION WILMONTON MN+IAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Aquic Hapludolls
TYPICAL PEDON: Wilmonton clay loam, on a plane slope of about 2 percent, on a ground moraine, in a cultivated field. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 8 inches; black (10YR 2/1) clay loam; weak fine subangular blocky structure; about 2 percent gravel; friable; neutral; abrupt smooth boundary. (7 to 10 inches thick)
A1--8 to 14 inches; black (10YR 2/1) clay loam; weak fine subangular blocky structure; friable; about 2 gravel; neutral; clear wavy boundary. (0 to 8 inches thick)
A2--14 to 17 inches; black (10YR 2/1) clay loam; moderate fine subangular blocky structure; friable; common very dark grayish brown (10YR 3/2) and grayish brown (2.5Y 5/2) worm casts; about 2 percent gravel; neutral; clear wavy boundary. (0 to 8 inches thick)
2Bw--17 to 25 inches; light olive brown (2.5Y 5/4) clay loam; moderate medium subangular blocky structure; firm; few very dark grayish brown (2.5Y 3/2) worm casts; thin stone line in upper part, about 5 percent gravel; few soft lime segregations in lower part; many fine faint olive (5Y 5/4) and few medium faint grayish brown (2.5Y 5/2) Fe depletions; slightly effervescent; slightly alkaline; abrupt wavy boundary. (6 to 22 inches thick)
2Bk--25 to 31 inches; olive brown (2.5Y 4/4) loam; moderate medium subangular blocky structure parting to weak coarse angular blocky; firm; few soft lime segregations and accumulations of soft powdery lime on pebbles and parting faces; about 5 percent gravel; many fine faint grayish brown (2.5Y 5/2) Fe depletions; strongly effervescent; moderately alkaline; clear wavy boundary. (3 to 16 inches thick)
2BC1--31 to 55 inches; light olive brown (2.5Y 5/4) loam; weak and moderate coarse and extremely coarse prismatic structure parting to weak coarse angular blocky; firm; about 5 percent gravel; many fine and medium faint grayish brown (2.5Y 5/2) Fe depletions; strongly effervescent; moderately alkaline.
2BC2--55 to 80 inches; grayish brown (2.5Y 5/2) clay loam; weak coarse prismatic structure parting to weak coarse angular blocky; firm; many medium prominent light olive brown (2.5Y 5/6) Fe concentrations; slightly effervescent; moderately alkaline.
TYPE LOCATION: Nobles County, Minnesota; about 2 miles southeast of Adrian; located about 1,300 feet west and 150 feet south of the northeast corner of section 20, T. 102 N., R. 42 W.; USGS Adrian topographic quadrangle; lat. 43 degrees 37 minutes 50 seconds N. and long. 95 degrees 53 minutes 46 seconds W., NAD 83.
RANGE IN CHARACTERISTICS: The depth to carbonates ranges from 20 to 40 inches. These soils lack or have a loamy mantle that is less than 30 inches thick over glacial till. The upper sediment contains 0 to 5 percent coarse fragments by volume and the glacial till contains 2 to 8 percent. The coarse fragments are of mixed lithology. A stone line as much as 4 inches thick and containing as much as 15 percent coarse fragments is at the contact of the two sediments in some pedons. The mollic epipedon ranges from 14 to 24 inches in thickness. In some pedons, worm casts comprise as much as 40 percent of the volume of the lower A or upper B horizons. The particle-size control section averages between 24 and 33 percent clay and typically 10 to 30 percent fine sand and coarser and ranges from 15 to 35 percent.
The A horizon has hue of 10YR, value of 2 or 3 and chroma of 1 or 2. It typically is clay loam, silty clay loam or loam. Reaction is slightly acid to neutral.
A BA horizon as thick as 8 inches is in some pedons.
The Bw horizon (when present) has hue of 10YR or 2.5Y, value of 3 to 5, and chroma of 2 to 4. It is loam, clay loam or silty clay loam. It is friable. It has a few dark concretions or stains (oxides) in the lower part in some pedons. Reaction is slightly acid to neutral.
The 2Bw horizons have hue of 10YR or 2.5Y, value of 3 to 5, and chroma of 2 to 4. It is loam or clay loam and is typically firm. It has a few dark concretions or stains (oxides) in the lower part in some pedons. Reaction is slightly acid to neutral.
The 2Bk horizon has hue of 10YR or 2.5Y, value of 5 or 6, and chroma of 2 to 4. It is loam or clay loam with or without coarser-textured wedges or seams. It is slightly alkaline or moderately alkaline with 15 to 25 percent calcium carbonate equivalent.
The 2BC horizon has hue of 10YR or 2.5Y, value of 5 or 6, and chroma of 2 to 4. It is loam or clay loam with or without coarser-textured wedges or seams. It is slightly alkaline or moderately alkaline with 10 to 20 percent calcium carbonate equivalent. The moist bulk density ranges from 1.6 to 1.8 g/cc.
COMPETING SERIES: These are the Arkton, Crippin, Floyd, Fostoria, Kensett, Merton, Nicollet, Ottosen, Readlyn and Snider soils in the same family. Arkton soils have carbonates above 20 inches. Crippin soils have carbonates beginning at depths of 10 inches or less. Floyd soils have thicker sola and coarser textured layers in the B horizons. Fostoria soils have loam sola and silt loam C horizons moderate permeability and friable consistence throughout. Kensett soils have hard limestone within depths of 40 inches. Merton and Readlyn soils have thicker and acid sola. Ottosen soils have friable B and C horizons and moderate permeability in the C horizon within depths of 40 inches below the surface. Nicollet soils typically are medium or slightly acid in the upper part of the B horizon and have friable C horizons. Snider soils formed in loamy alluvium on benches.
GEOGRAPHIC SETTING: Wilmonton soils have slightly concave to slightly convex slopes on dissected ground moraines. Slopes are long and uniform with gradient of 0 to 3 percent and lengths of 150 to 400 feet. The Wilmonton soils typically formed in a thin layer of loess, ablation till or pedisediments and firm, clay loam or loam till. Mean annual air temperature ranges from 45 to 52 degrees F. Mean annual precipitation ranges from 25 to 28 inches. Frost-free period ranges from 145 to 160 days. Elevation ranges from 900 to 1,600 feet above sea level.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Everly, Letri, and Storden, soils which are members of a hydrosequence with Wilmonton soils. The moderately well drained Everly and well drained Storden soils commonly are downslope or on more sloping terrain. The poorly drained Letri soils are on nearby less sloping areas.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained. Surface runoff is low. Permeability is moderately slow. Seasonal high saturation occurs at depths as shallow as 1.5 feet, typically in spring in normal years.
USE AND VEGETATION: Largely cropped to corn, legume hay, small grains, and soybeans. Native vegetation is tall grass prairie.
DISTRIBUTION AND EXTENT: Southwestern Minnesota and northwestern Iowa. Moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Nobles County, Minnesota, 1970.
REMARKS: Diagnostic horizons and properties recognized in this pedon are: mollic epipedon - the zone from the surface to a depth of 17 inches (Ap, A1, and A2 horizons); cambic horizon - the zone from 17 to 60 inches (2Bw, 2Bk and 2BC horizons); Aquic moisture regime.
ADDITIONAL DATA: Refer to MAES Central File Code No. 791 for results of some laboratory analyses of the typical pedons.