LOCATION FOLDAHL MN+NDEstablished Series
TAXONOMIC CLASS: Sandy over loamy, mixed, superactive, frigid Oxyaquic Hapludolls
TYPICAL PEDON: Foldahl loamy fine sand on a west facing slope of 1 percent in a cultivated field. (Colors are for moist soil unless otherwise stated)
Ap--0 to 9 inches; black (10YR 2/1) loamy fine sand; very dark gray (10YR 3/1) dry; weak medium subangular blocky structure parting to weak fine granular; very friable; few fine roots; neutral; abrupt smooth boundary.
A--9 to 12 inches; very dark brown (10YR 2/2) loamy fine sand; weak fine subangular blocky structure; very friable; neutral; few fine roots; gradual wavy boundary. (Combined A horizons 7 to 16 inches thick)
Bw1--12 to 22 inches; dark brown (10YR 3/3) fine sand; weak fine subangular blocky structure; very friable; neutral; clear wavy boundary.
Bw2--22 to 30 inches; dark brown (10YR 4/3) fine sand; single grain; loose; few fine distinct yellowish brown (10YR 5/6) redoximorphic concentrations and few fine faint grayish brown (10YR 5/2) redoximorphic depletions; neutral; gradual wavy boundary. (Combined Bw horizons 8 to 24 inches thick)
2BCk--30 to 44 inches; light brownish gray (2.5Y 6/2) fine sandy loam; massive; friable; few fine distinct olive brown (2.5Y 4/4) redoximorphic concentrations; 8 percent gravel; strongly effervescent; moderately alkaline; gradual wavy boundary.
2C1--44 to 58 inches; grayish brown (2.5Y 5/2) fine sandy loam; weak thin platy soil fragments; friable; common fine distinct light olive brown (2.5Y 5/4) redoximorphic concentrations; 8 percent gravel; slightly effervescent; moderately alkaline; clear wavy boundary.
2C2--58 to 70 inches; grayish brown (2.5Y 5/2) fine sandy loam; weak thin platy soil fragments; firm; common medium prominent brownish yellow (10YR 6/6) redoximorphic concentrations; 5 percent gravel; common fine irregularly shaped white (10YR 8/1) masses of carbonate; slightly effervescent; moderately alkaline; clear wavy boundary.
2C3--70 to 83 inches; light olive brown (2.5Y 5/3) fine sandy loam; weak thin platy soil fragments; firm; common medium prominent brownish yellow (10YR 6/6) and few fine prominent yellowish brown (10YR 5/6) redoximorphic concentrations; 6 percent gravel; few fine irregularly shaped white (10YR 8/1) masses of carbonate and few fine black (10YR 2/1) manganese stains; slightly effervescent; moderately alkaline.
TYPE LOCATION: Polk County, Minnesota; 120 feet north and 510 feet west of the southeast corner of sec. 15, T. 147 N., R. 45 W.
RANGE IN CHARACTERISTICS: Depth to carbonates range from 16 to 32 inches. The thickness of the sandy sediments over the loamy sediments is 20 to 40 inches. The upper sediment typically does not have rock fragments in the upper part, but it has as much as 8 percent in some pedons. A lag line as thick as 6 inches and containing as much as 35 percent rock fragments is at the contact of the two sediments in some pedons. The till contains from 1 to 15 percent of rock fragments of mixed lithology. The mollic epipedon ranges from 7 to 21 inches in thickness. The lower sediment is loamy but with less than 50 percent of fine sand and coarser particles. Redoximorphic depletions with chroma of 2 or less begin within depths of 40 inches.
The A horizon has value of 2 or 3 and chroma of 1 or 2. It is loamy sand, loamy fine sand, sandy loam, very fine sandy loam, or fine sandy loam. It is slightly acid to slightly alkaline.
The Bw horizon has value of 3 or 4 and chroma of 2 to 4. It is sand, fine sand, loamy sand, or loamy fine sand. It is neutral or slightly alkaline.
Some pedons have a Bk horizon that has the same range in texture as the Bw horizon and range in hue of 10YR or 2.5Y, value of 5 to 7, and chroma of 2 to 4.
The 2BCk and 2C horizon have a matrix with hue of 10YR or 2.5Y, value of 5 to 7, and chroma of 2 to 4. They have few to many redoximorphic features. They are sandy loam, fine sandy loam, loam, silt loam or clay loam. They are slightly alkaline or moderately alkaline. Some pedons do not have a 2BCk horizon.
Some pedons have a 2Bk or 2Bw horizon with the similar range in color and texture as the 2BCk and 2C horizons.
Some pedons have a C horizon in the sandy sediment. Where present, it has hue of 10YR or 2.5Y, value of 5 or 6, and chroma of 2 to 4. It commonly has redoximorphic features. It has the same range in texture as the Bw horizon. It is slightly alkaline or moderately alkaline.
COMPETING SERIES: There are no other series are in this family.
GEOGRAPHIC SETTING: These soils have plane or convex slopes with gradient of 0 to 6 percent on lake plains. They formed in 20 to 40 inches of sandy lacustrine sediments over calcareous loamy till or lacustrine sediments. Mean annual air temperature is 38 to 44 degrees F. Mean annual precipitation is 19 to 27 inches. Frost-free days range from 90 to 140. Elevation ranges from 800 to 1600 feet above sea level.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Grimstad, Kratka and Strathcona soils, which formed in similar sediments, and the Flaming soils. Grimstad and Strathcona soils contain carbonates throughout. Kratka and Strathcona soils are poorly drained and are in lower lying positions. The Flaming soils do not have loamy 2C horizons within depths of 40 inches.
DRAINAGE AND PERMEABILITY: Moderately well drained. Runoff is negligible or very low. Permeability is rapid in the upper sediment and moderately slow or moderate in the lower sediment. Depth to a seasonal high water table is 2.5 to 5.0 feet at some time from April through June in most years.
USE AND VEGETATION: About two-thirds of the Foldahl soils are cultivated. Small grains, sunflowers, and forages are the principal crops. The remainder is used for pasture or is forested. Native vegetation is tall grass prairie or savanna.
DISTRIBUTION AND EXTENT: Northwestern Minnesota in the Red River Valley. The soil is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Kittson County, Minnesota, 1975.
REMARKS: Diagnostic horizons and features in this pedon are: mollic epipedon - 0 to 12 inches (Ap and A horizons) - the Bw1 horizon has the color, but not the organic matter content to be mollic; oxyaquic subgroup criteria supporting information - redoximorphic concentrations within 40 inches (Bw2 and 2C1 horizons.