LOCATION SOUDAN MNEstablished Series
TAXONOMIC CLASS: Coarse-loamy, isotic, frigid Oxyaquic Dystrudepts
TYPICAL PEDON: Soudan sandy loam on a linear 3 percent slope in a forested area. (Colors are for moist soil unless otherwise stated.)
A--0 to 3 inches; black (10YR 2/1) sandy loam; moderate fine granular structure; very friable; many medium and common fine roots; 2 percent gravel, 2 percent stones, 2 percent boulders; strongly acid; clear smooth boundary. (2 to 5 inches thick.)
Bw1--3 to 9 inches; dark brown (7.5YR 3/3) sandy loam; weak medium subangular blocky structure; very friable; many medium and common fine roots; 2 percent gravel, 2 percent stones, 2 percent boulders; strongly acid; gradual smooth boundary.
Bw2--9 to 17 inches; brown (7.5YR 4/4) sandy loam; weak medium and coarse subangular blocky structure; very friable; common fine and few medium roots; 2 percent gravel, 2 percent cobbles, 5 percent stones, 2 percent boulders; strongly acid; gradual smooth boundary.
Bw3--17 to 36 inches; yellowish brown (10YR 5/4) loamy sand; weak medium subangular blocky structure; very friable; common medium roots; 5 percent gravel, 2 percent cobbles, 5 percent stones, 2 percent boulders; moderately acid; clear smooth boundary. (combined thickness of Bw horizons is 18 to 37 inches.)
2BC--36 to 57 inches; light olive brown (2.5Y 5/4) very gravelly sandy loam; weak thick platy structure parting to weak fine subangular blocky; firm; few fine roots; few medium prominent yellowish brown (10YR 5/6) Fe concentrations; 40 percent gravel, 5 percent cobbles, 1 percent stones, 1 percent boulders; moderately acid; clear wavy boundary. (0 to 25 inches thick.)
2Cd--57 to 80 inches; light brownish gray (2.5Y 6/2) very gravelly fine sandy loam; massive; firm; few medium prominent yellowish brown (10YR 5/6) Fe concentrations; 30 percent gravel, 5 percent cobbles, 1 percent stones, 1 percent boulders; moderately acid.
TYPE LOCATION: St. Louis County, Minnesota; about 7 miles south and 2 miles west of Tower; 1300 feet south and 400 feet east of the northwest corner of sec. 12, T. 60 N., R. 16 W.; USGS Biwabik NE Quadrangle, latitude 47 degrees 42 minutes 30 seconds N. longitude 92 degrees 19 minutes 28 seconds W. NAD 27.
RANGE IN CHARACTERISTICS: The thickness of the mantle ranges from 20 to 40 inches. Depth to dense till is 40 to 60 inches. Depth to free carbonates is greater than 80 inches. Redox concentrations occur above 40 inches.
The A horizon has hue of 10YR, value of 2 or 3 and chroma of 1 or 2. Texture is sandy loam or fine sandy loam. Rock fragment content ranges from 0 to 15 percent by volume, with 0 to 10 percent gravel, 0 to 5 percent cobbles, 0 to 10 percent stones, and 0 to 3 percent boulders. Reaction is very strongly acid to slightly acid.
The Bw horizon has hue of 7.5YR or 10YR, value of 3 to 5, and chroma 3 to 6. Texture in the upper part is sandy loam or fine sandy loam. Texture in the lower part is loamy sand, loamy fine sand, sand or fine sand. Rock fragment content ranges from 0 to 15 percent by volume, with 0 to 10 percent gravel, 0 to 5 percent cobbles, 0 to 10 percent stones, and 0 to 3 percent boulders. Reaction is very strongly acid to slightly acid.
The 2BC horizon has hue of 10YR, value of 4 to 6 and chroma of 3 to 6. Texture is fine sandy loam, sandy loam, coarse sandy loam, loamy sand, or loamy coarse sand in the fine-earth fraction. Rock fragment content averages 35 to 60 percent by volume, with 15 to 40 percent gravel, 5 to 25 percent cobbles, 0 to 15 percent stones and 0 to 10 percent boulders. Reaction is strongly acid to slightly acid.
The 2Cd horizon has hue of 2.5Y, or 10YR, value of 4 to 6, and chroma of 2 to 4. It is fine sandy loam, sandy loam, coarse sandy loam, loamy sand, or loamy coarse sand in the fine-earth fraction. Rock fragment content averages 35 to 60 percent by volume, with 15 to 40 percent gravel, 5 to 25 percent cobbles, 0 to 15 percent stones and 0 to 10 percent boulders. Reaction is strongly acid to slightly acid.
COMPETING SERIES: These are no competing series.
GEOGRAPHIC SETTING: Soudan soils are on linear or convex slopes on till plains and till-mantled bedrock uplands. Slopes range from 1 to 8 percent. They formed in a mantle of outwash or eolian material and underlying dense till. Mean annual air temperature is 36 to 40 degrees F. Mean annual precipitation is 27 to 30 inches. The frost-free period ranges from 90 to 120 days. Elevation above sea level is 1400 to 1900 feet.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Babbitt(T), Cathro, Cloquet, Conic, Eaglesnest(T), Eveleth(T) and Wahlsten(T) soils. Somewhat poorly drained Babbitt, moderately well drained Eaglesnest and well drained Eveleth soils do not have sandy textures above the dense till. The very poorly drained Cathro soils formed in organic materials and are in depressions. The well drained Cloquet soils formed in a mantle of loess and underlying outwash. The well drained Conic and moderately well drained Wahlsten soils have bedrock at 20 to 40 inches.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Moderately well drained. Runoff is low. Saturated hydraulic conductivity is 42.34 to 141.14 micrometers per second (6 to 20 inches per hour) in the upper part and .01 to 1.41 micrometers per second (.0015 to .20 inches per hour) the underlying till. Perched seasonal high saturation is at a depth as high as 2.0 feet during the period April through June and October through November in years of normal preciptiation.
USE AND VEGETATION: Most areas are forested. Principle trees are aspen, paper birch, red maple, balsam fir, white spruce, red pine and jack pine. Native vegetation is mixed coniferous and deciduous forest.
DISTRIBUTION AND EXTENT: MLRA-93A. Northeast Minnesota,Small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: St. Louis County, Minnesota (Virginia subset) 2006.
REMARKS: Diagnostic horizons and features recognized in this pedon are: Ochric epipedon - the zone from the surface to a depth of 3 inches (A horizon); cambic horizon - the zone from 3 to 17 inches (Bw1 & Bw2 horizons); oxyaquic subgroup - saturated above a depth of 40 inches for at least one month in most years.
These soils may classify as spodosols if the chemical requirement is met. Albic horizons are in less than 25 percent of all pedons based on field documentation. Lab data will be obtained in the future.
ADDITIONAL DATA: Soil Interpretation Number MN0868.