LOCATION TOLNA NDEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, frigid Aquic Hapludolls
TYPICAL PEDON: Tolna loam - on a concave slope of less than 1 percent. (Colors are for dry soil unless otherwise stated)
Ap--0 to 7 inches; dark gray (10YR 4/1) loam, black (10YR 2/1) moist; moderate fine granular structure; hard, friable, slightly sticky and slightly plastic; many fine roots; common fine pores; few pebbles; medium acid; abrupt smooth boundary. (5 to 12 inches thick)
Bw1--7 to 10 inches; dark grayish brown (2.5Y 4/2) loam, very dark grayish brown (2.5Y 3/2) moist; moderate medium prismatic structure parting to moderate coarse and medium platy; hard, friable, sticky and slightly plastic; common fine roots; clay films on faces of prisms; few uncoated sand grains on faces of peds; about 5 percent gravel; medium acid; clear wavy boundary.
Bw2--10 to 17 inches; light brownish gray (2.5Y 6/2) loam, dark grayish brown (2.5Y 4/2) moist; few fine prominent yellowish brown (10YR 5/4) mottles; moderate medium prismatic structure parting to moderate thick and medium platy; hard, friable, sticky and slightly plastic; common fine roots; many fine pores; faint clay films and few uncoated sand grains on faces of peds; about 5 percent gravel; medium acid; clear wavy boundary. (Combined Bw horizons 6 to 20 inches thick)
2Bw3--17 to 30 inches; pale olive (5Y 6/3) fine sandy loam, olive (5Y 4/3) moist; common fine prominent yellowish brown (10YR 5/4) mottles; very weak coarse prismatic structure parting to weak coarse, medium, and fine subangular blocky; soft, very friable, slightly sticky and slightly plastic; few fine roots; medium acid; clear wavy boundary. (5 to 15 inches thick)
2C1--30 to 40 inches; light brownish gray (2.5Y 6/2) gravelly loamy coarse sand, dark grayish brown (2.5Y 4/2) moist; common fine prominent yellowish brown (10YR 5/4) mottles; single grain; loose; about 30 percent gravel; about 40 percent shale in the 0.1 to 76 mm fraction; slightly acid; clear wavy boundary.
2C2--40 to 60 inches; light olive gray (5Y 6/2) and light brownish gray (2.5Y 6/2) loamy coarse sand, olive gray (5Y 4/2) and dark grayish brown (2.5Y 4/2) moist; single grain; loose; about 10 percent gravel; about 70 percent shale in the 0.1 to 76 mm fraction; slight effervescence; slightly alkaline.
TYPE LOCATION: Eddy County, North Dakota; about 10.5 miles east and 3 miles north of New Rockford; 2,440 feet east and 1,000 feet south of the northwest corner, sec. 18, T. 149 N., R. 64 W.
RANGE IN CHARACTERISTICS: The thickness of solum and depth to the 2C horizon typically is 24 to 30 inches, but ranges from 16 to 40 inches. The thickness of the mollic epipedon ranges from 7 to 16 inches. The A and B horizons are medium acid or slightly acid and the 2C horizon is slightly acid to moderately alkaline.
The A horizon has hue of 10YR, value of 2 or 3 moist, and chroma of 1. It is loam.
The Bw horizon has hue of 10YR to 5Y, value of 4 to 6 and 3 to 5 moist, and chroma of 1 to 3. It is loam, sandy loam or fine sandy loam averaging between 18 and 24 percent clay and 25 to 40 percent silt. Mottles are few or common, faint to prominent, and commonly increase in abundance in the lower part of the horizon.
The 2C horizon has hue of 2.5Y or 5Y, value of 6 and 4 moist, and chroma of 2. It is stratified sand, loamy coarse sand, loamy sand or coarse sand containing 5 to 40 percent gravel. It contains more than 20 percent shale in the 0.1 to 76 mm fraction.
COMPETING SERIES: These are the Firth, Hagensville, Ogdensburg and Sundell series in the same family and the Binford, Brantford, Walum and Warsing series. All of these soils, except Ogdensburg, are less acid in the solum. In addition, Firth and Hagensville soils do not have sand and gravel 2C horizons; Sundell soils are underlain by limestone bedrock; Binford soils are sandy and are well drained; Brantford soils do not have the transitional 2Bw3 horizon as much as 5 inches thick and are well drained; Walum soils are sandy; and Warsing soils contain less than 20 percent shale in the 0.1 to 76 mm fraction of the 2C horizon. Ogdensburg soils have sandstone bedrock at depths of less than 40 inches and occur in areas having more than 27 inches of precipitation.
GEOGRAPHIC SETTING: Tolna soils are in depressions and shallow swales on glacial outwash plains. Slope gradient is 0 to 1 percent. The soils formed in loamy outwash materials overlying sand and gravel containing appreciable amounts of shale. The climate is cool, subhumid, with a mean annual temperature ranging from 38 to 44 degrees F, and mean annual precipitation from 16 to 20 inches. Most of the precipitation falls in the spring and summer.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Binford, Walum and Warsing soils and the Divide and Kensal soils. All the associated soils are on outwash plains and commonly on slightly higher elevations in the landscape. Binford, Kensal, Walum and Warsing soils are better drained than the Tolna soils. Divide soils have a calcic horizon within a depth of 16 inches. Kensal soils are fine-loamy over sandy or sandy-skeletal.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained. Tolna soils receive runoff from higher areas. Permeability is moderate in the solum and rapid or very rapid in the substratum. The seasonal water table is at a depth of less than 24 inches for only a short time when the soil is not frozen.
USE AND VEGETATION: Most areas are cropped to small grains, hay and pasture. Native vegetation was needleandthread, western wheatgrass and blue grama.
DISTRIBUTION AND EXTENT: East-central North Dakota. The soil is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Eddy County, North Dakota, 1970.
REMARKS: Revised 12/91.
Diagnostic horizons and features recognized in this pedon are: mollic epipedon - the zone from the surface of the soil to a depth of 10 inches (Ap and Bw1 horizons); Cambic horizon - the zone from 10 to 30 inches (Bw2 and 2Bw3 horizons); aquic subgroup criteria - mottles with chroma of 2 or less within 1 m (Bw2 and 2C1 horizons).
ADDITIONAL DATA: Laboratory Data S65ND-14-2 and S65ND-14-3.