LOCATION LA PRAIRIE ND+MN SDEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Cumulic Hapludolls
TYPICAL PEDON: La Prairie silt loam - on a flat slope of less than 1 percent in a cultivated field. (Colors are for moist soil unless otherwise stated. When described, the soil was moist throughout.)
Ap--0 to 8 inches; black (10YR 2/1) silt loam, dark gray (10YR 4/1) dry; weak medium subangular blocky structure parting to moderate medium and fine granular; slightly hard, friable, slightly sticky and slightly plastic; many fine roots; many fine pores; many worm casts; slightly alkaline; abrupt smooth boundary.
A--8 to 19 inches; black (10YR 2/1) silt loam, dark gray (10YR 4/1) dry; weak coarse prismatic structure parting to weak coarse and medium subangular blocky; hard, friable, slightly sticky and slightly plastic; many fine roots; many fine pores; slightly alkaline; clear wavy boundary. (Combined A horizons 12 to 30 inches thick)
Bw--19 to 28 inches; very dark grayish brown (10YR 3/2) and very dark brown (10YR 2/2) silt loam, grayish brown (10YR 5/2) and dark grayish brown (10YR 4/2) dry: weak coarse prismatic structure parting to weak coarse subangular blocky; hard, friable, slightly sticky and slightly plastic; common fine roots; many fine pores; few fine masses of carbonates; slight effervescence; moderately alkaline; gradual wavy boundary. (0 to 35 inches thick)
C1--28 to 44 inches; very dark grayish brown (10YR 3/2) silt loam, grayish brown (10YR 5/2) dry; weak coarse and medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; few roots; common fine pores; several oval krotovinas 1 to 3 inches in diameter; few fine masses of carbonates; slight effervescence; moderately alkaline; gradual wavy boundary.
C2--44 to 60 inches; brown (10YR 4/3) silt loam, brown (10YR 5/3) dry; weak thin platy structure; hard, friable, slightly sticky and slightly plastic; slight effervescence; moderately alkaline.
TYPE LOCATION: Cass County, North Dakota; about 8 1/2 miles south and 1/2 mile east of Embden; 2,100 feet west and 1,920 feet north of the southeast corner, sec. 18, T. 137 N., R. 53 W.
RANGE IN CHARACTERISTICS: Depth to carbonates ranges from 0 to 40 inches. The mollic epipedon ranges from 16 to over 40 inches in thickness. The 10- to 40-inch control section is loam, clay loam, silt loam or silty clay loam averaging 18 to 35 percent clay and 15 to 40 percent fine sand and coarser. The soil is neutral to moderately alkaline throughout. Channeled and nonflooded phases are recognized.
The A horizon has hue of 10YR or is neutral, value of 2 or 3 and 3 or 4 dry, and chroma of 1 or less. It is loam, silt loam, clay loam or silty clay loam. Ab horizons are in some pedons.
The Bw horizon has hue of 10YR or 2.5Y, value of 2 to 4 and 3 to 5 dry, and chroma of 1 to 3. It is loam, clay loam, silt loam or silty clay loam. Secondary carbonates, as threads or fine to coarse masses, are in the lower B horizon in some pedons. Some pedons have a Bk horizon.
The C horizon has hue of 10YR, 2.5Y or 5Y, value of 3 to 5 and 4 to 7 dry, and chroma of 1 to 4. It is loam, clay loam, silt loam or silty clay loam. Sandy clay loam is allowed below 40 inches. The C horizon has faint or distinct redoximorphic concentrations in some pedons. Some pedons below a depth of 40 inches contain strata with up to 5 percent rock fragments and textures of very coarse sand to clay.
COMPETING SERIES: There are the Darnen, Delette, Everts, Frolic and Southhaven series. Darnen soils are well drained, have a thicker solum and generally are deeper to carbonates. They occur on moraines, formed in alluvium from till and are not subject to flooding. Delette, Frolic and Southhaven soils do not have carbonates within 40 inches. Everts soils have sandy textures below a depth of 40 inches.
GEOGRAPHIC SETTING: La Prairie soils are on level to gently sloping terraces, bottom lands and in swales of intermittent streams. Slope ranges from 0 to 6 percent. The soils formed in alluvium. The mean annual air temperature ranges from 37 to 45 degrees F, and the mean annual precipitation from 15 to 23 inches. Most of the precipitation comes in the spring and summer.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Aastad, Barnes, Cashel, Fairdale, Forman, Gardena, LaDelle, Lamoure, Ludden, Svea, Wahpeton and Walsh soils. Aastad, Barnes, Forman and Svea soils are on nearby till uplands and Gardena and Walsh soils are on nearby deltas, fans and lake plains. These soils have a regular decrease in organic matter content with depth. In addition, Barnes and Forman soils have mollic epipedons less than 16 inches in thickness and Gardena soils are coarse-silty. Cashel, Lamoure and Ludden soils are on nearby lower lying bottom lands. Cashel soils are somewhat poorly drained and have fine textures. Lamoure soils are poorly drained and are fine-silty. Ludden soils are poorly drained and have fine textures. Fairdale and LaDelle soils are on similar positions as La Prairie soils. Fairdale soils have fine stratification below the A horizon. LaDelle soils are fine-silty. Wahpeton soils are on higher lying levees and have fine textures.
DRAINAGE AND PERMEABILITY: Moderately well drained. Runoff is negligible to low depending on slope. Permeability is moderate. The soils are flooded for short periods when streams overflow. A seasonal high water table is at depth of 3 to 5 feet at some time during the period of April through June.
USE AND VEGETATION: Soils are cropped to spring seeded small grains, row crops hay and pasture. Native vegetation was big bluestem, green needlegrass, porcupinegrass, western wheatgrass, a variety of forbs; and scattered trees and shrubs as boxelder, chokecherry, cottonwood, elm and prairie rose.
DISTRIBUTION AND EXTENT: Eastern North Dakota and adjacent areas of northeastern South Dakota and western Minnesota. The series is of large extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Spink County, South Dakota, 1955.
REMARKS: Diagnostic horizons and features recognized in this pedon are: mollic epipedon - the zone from the surface of the soil to a depth of 28 inches (Ap, A, and Bw horizons); the C1 horizon has the color but not the organic matter content to be part of the mollic epipedon.
Some sandy substratum phases of the La Prairie soils may fit into the Everts series.