LOCATION WAHPETON           ND+MN
Established Series
RLH-CJH
11/2002

WAHPETON SERIES


The Wahpeton series consists of very deep, moderately well drained, moderately or moderately slowly permeable soils that formed in clayey alluvium. These soils are on levees and low terraces of large streams and have slopes of 0 to 15 percent. Mean annual air temperature is 39 degrees F, and mean annual precipitation is 19 inches.

TAXONOMIC CLASS: Fine, smectitic, frigid Typic Hapluderts

TYPICAL PEDON: Wahpeton silty clay - on a slope of less than 1 percent under cropland. Where described the soil was moist throughout. (Colors are for dry soil unless otherwise stated)

Ap--0 to 8 inches; very dark gray (10YR 3/1) silty clay, black (10YR 2/1) moist; strong very fine angular blocky structure; very hard, friable; sticky and plastic; many fine roots; many fine pores; slight effervescence; slightly alkaline; abrupt smooth boundary.

A--8 to 23 inches; dark gray (10YR 4/1) silty clay, black (10YR 2/1) moist; strong medium subangular blocky structure parting to strong very fine angular blocky; very hard, firm; sticky and plastic; common fine roots; common fine pores; faces of peds have slick, shiny surface when moist; gray (10YR 5/1) band crosses horizon at depths of 12 to 14 inches; slight effervescence; slightly alkaline; clear smooth boundary. (Combined A horizons 16 to 40 inches thick)

C--23 to 27 inches; gray (10YR 5/1) silty clay, very dark gray (10YR 3/1) moist; strong very fine angular blocky structure; hard, firm; sticky and plastic; few roots, common fine pores; slight effervescence; slightly alkaline; clear smooth boundary. (2 to 10 inches thick)

Assb--27 to 38 inches; dark gray (10YR 4/1) silty clay, black (10YR 2/1) moist; strong medium subangular blocky structure parting to strong very fine angular blocky; hard, firm; sticky and plastic; few roots; common fine pores; slickensides on vertical faces of peds; few fine masses of carbonates; slight effervescence; slightly alkaline; gradual wavy boundary. (0 to 15 inches thick)

Css--38 to 47 inches; gray (10YR 5/1) silty clay, very dark gray (10YR 3/1) moist; moderate medium prismatic structure parting to strong very fine angular blocky; very hard, firm; sticky and plastic; few fine roots; common fine pores; distinct slickensides on faces of peds; common medium masses of carbonates; strong effervescence; slightly alkaline; gradual wavy boundary. (0 to 10 inches thick)

A'ssb--47 to 60 inches; dark gray (10YR 4/1) silty clay, black (10YR 2/1) moist; moderate medium prismatic structure parting to strong fine and very fine angular blocky; very hard, firm; sticky and plastic; few fine pores; slickensides are vertical but slant to 15 degrees from vertical below depths of 54 inches; few masses of carbonates; slight effervescence; slightly alkaline.

TYPE LOCATION: Walsh County, North Dakota; about 11 1/2 miles east of 1/2 mile north of Grafton; 1,640 feet south and 380 feet west of the northeast corner, Sec. 13, T. 157 N., R. 51 W. (90 feet south of road, 800 feet east of fence on east side of woods)

RANGE IN CHARACTERISTICS: The 10- to 40-inch control section typically averages between 50 to 60 percent clay, but ranges from 35 to 60 percent. The mollic epipedon ranges from 16 to 40 inches in thickness. The soil commonly has one or more Ab horizons separated by C horizons below depths of 24 inches. Many pedons when dry have cracks which extend from the surface to depths of 60 inches or more. Slickensides are in the lower half of most pedons. Some pedons do not have carbonates to depths of 36 inches and do not have segregated carbonates below these depths.

The A horizon has hue of 10YR, 2.5Y or 5Y, value of 3 to 5 and 2 or 3 moist, and chroma of 1. Some pedons have chroma of 2 moist in the lower part of the A horizon when the soil is crushed. It is clay or silty clay. It is slightly acid to slightly alkaline. The lower boundary of the A horizon ranges from gradual or clear smooth to irregular and tongued. Some pedons have a Bw or Bk horizon.

The C horizon has hue of 10YR, 2.5Y or 5Y, value of 4 to 6 and 3 to 5 moist, and chroma of 1 or 2. It is clay, silty clay or silty clay loam. It is neutral to moderately alkaline.

The Ab horizons have hue of 10YR, 2.5Y, 5Y or are neutral, value of 3 to 5 and 2 or 3 moist, and chroma of 2 or less. They are clay, silty clay or silty clay loam. They are neutral or slightly alkaline.

COMPETING SERIES: These are the Pekay and Sinai series. Pekay soils have horizons of carbonate and gypsum accumulations and are well drained. Sinai soils have a regular decrease in organic matter and do not have buried horizons.

GEOGRAPHIC SETTING: Wahpeton soils are on level to strongly sloping levees and low terraces of large streams. Slope gradients commonly are less than 2 percent but some on levee and terrace edges range to 15 percent. The soil formed in clayey alluvium. The climate is cool, subhumid. The mean annual air temperatures range from 36 to 45 degrees F, and mean annual precipitation from 16 to 23 inches. Most of the moisture falls in the spring and summer.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bearden, Cashel, Dovray, Fairdale, Fargo, Hegne, La Prairie and Overly soils. Bearden and Overly soils are on higher elevations on the nearby lake plains. They are fine-silty. Cashel, Fairdale and La Prairie soils are on flood plains and low terraces that are lower on the landscape than the Wahpeton soils. Cashel soils do not have mollic epipedons. Fairdale and La Prairie soils are fine-loamy. The poorly drained Dovray, Fargo and Hegne soils are on nearby glacial lake plains. Dovray and Fargo soils have Bw horizons. Hegne soils have a calcic horizon within a depth of 16 inches.

DRAINAGE AND PERMEABILITY: Moderately well drained. Runoff is slow or medium. Permeability is moderate or moderately slow. These soils flood occasionally in the early spring.

USE AND VEGETATION: Most areas are used to grow small grains and some row crops, such as soybeans and sugar beets. Native vegetation was western wheatgrass, big bluestem, green needlegrass, blue grama, little bluestem, a variety of forbs, shrubs, and such trees as American elm, oak, boxelder and cottonwood.

DISTRIBUTION AND EXTENT: Eastern North Dakota and northwestern Minnesota along the Red River and other large streams. The soil is of moderate extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota

SERIES ESTABLISHED: Richland County, North Dakota, June 1970.

REMARKS: Revised 5/94.

The site will be redescribed to better describe the Vertisol characteristics.

Diagnostic horizons and features recognized in this pedon are: mollic epipedon - the zone from the surface of the soil to a depth of 23 inches (Ap and A horizon), the C horizon has the color but not the organic matter content to be mollic; Vertisol criteria - silty clay texture throughout, cracks (range in characteristics), and slickensides below 27 inches (Assb, Css, and A'ssb horizons).

ADDITIONAL DATA: S67NDak-50-1(1-8) and S67NDak-50-2(1-4).


National Cooperative Soil Survey
U.S.A.