LOCATION ARNEGARD ND+MT SD WYEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Pachic Haplustolls
TYPICAL PEDON: Arnegard loam - cultivated. (Colors are for dry soil unless otherwise stated)
Ap--0 to 6 inches; dark grayish brown (10YR 4/2) loam, very dark brown (10YR 2/2) moist; weak fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; common fine and many very fine roots; neutral; clear smooth boundary.
A--6 to 13 inches; dark grayish brown (10YR 4/2) loam, very dark brown (10YR 2/2) moist; weak medium prismatic structure parting to weak fine subangular blocky; slightly hard, very friable, slightly sticky and slightly plastic; many very fine roots; neutral; gradual wavy boundary. (Combined A horizons 5 to 20 inches thick)
Bw1--13 to 27 inches; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; weak medium prismatic structure parting to weak medium subangular blocky; hard, friable, slightly sticky and slightly plastic; many very fine roots; neutral; clear wavy boundary.
Bw2--27 to 36 inches; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 4/2) moist; weak medium prismatic structure parting to weak medium subangular blocky; slightly hard, very friable, slightly sticky and slightly plastic; common very fine roots; slightly alkaline; clear wavy boundary. (Combined Bw horizons 8 to 40 inches thick)
Bk--36 to 60 inches; light brownish gray (2.5Y 6/2) loam, dark grayish brown (2.5Y 4/2) moist; weak medium prismatic structure parting to weak medium subangular blocky; slightly hard, friable, slightly sticky and slightly plastic; common very fine roots; few fine irregular masses of lime; strong effervescence; moderately alkaline. (0 to 25 inches thick)
TYPE LOCATION: Hettinger County, North Dakota; 1,575 feet north and 1,700 feet west of the southeast corner, sec. 35, T. 132 N., R. 93 W.
RANGE IN CHARACTERISTICS: The mollic epipedon ranges from 16 to more than 30 inches in thickness and includes all or part of the Bw horizon. The soil typically has masses or disseminated carbonates within a depth of 40 inches but they range in depth from 16 to more than 60 inches. The soil has less than 10 percent rock fragments throughout. Some pedons have an Ab horizon. Saline phases are recognized.
The A horizon has hue of 10YR, value of 3 or 4 and 2 or 3 moist, and chroma of 2. It is loam, silt loam or clay loam. It is slightly acid to slightly alkaline. Some pedons have BA horizons.
The Bw horizon has hue of 10YR or 2.5Y, value of 3 to 5 and 2 to 4 moist, and chroma of 2 to 4. It is loam, silt loam, or clay loam containing less than 30 percent clay. It is slightly acid to slightly alkaline.
The Bk horizon has hue of 2.5Y or 10YR, value of 4 to 7 dry and 3 to 5 moist, and chroma of 2 to 4. It is typically loam but includes fine sandy loam to clay loam. It is slightly alkaline or moderately alkaline.
Some pedons have a C horizon. When present it has hue of 2.5Y or 10YR, value of 5 to 7 dry and 4 or 5 moist, and chroma of 2 to 4. It is neutral to moderately alkaline. It typically is loam but includes clay loam.
Below a depth of 30 inches textures of fine sandy loam and sandy loam are allowed and below a depth of 40 inches textures of loamy fine sand and silty clay loam are allowed.
COMPETING SERIES: These are the Bowery, Falkirk, Garlips, Roseglen and Shawa series. Bowery soils have more than 10 percent rock fragments in the Bw horizon. Falkirk soils have a gravelly loam 2C horizon and glacial till within a depth of 40 inches. Garlips and Roseglen soils have a calcic horizon. In addition, Roseglen soils formed in lacustrine sediments. Shawa soils do not have Bw horizons and formed in alluvium primarily from igneous rocks.
GEOGRAPHIC SETTING: Arnegard soils are on level to moderately steep upland swales, terraces, fans and foot slopes on residual plains, glacial till plains or moraines. They formed in mixed, loamy alluvium from calcareous sedimentary beds or glacial till. Slope typically is 1 or 2 percent but ranges from 0 to 25 percent. The mean annual air temperature is 34 to 45 degrees F, and the mean annual precipitation is 12 to 18 inches, most of which falls during spring and summer.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Amor, Farland, Grail, Grassna, Max, Morton, Parshall, Sen, Shambo, Temvik, Vebar and Williams soils. All of these soils, except Grail, Grassna and Parshall soils, have mollic epipedons less than 16 inches thick. Amor, Morton, Sen and Vebar soils formed in residual materials and are on nearby convex slopes. Farland and Shambo soils are on nearby terraces. Max, Williams and Temvik soils formed in glacial till. Grail, Grassna and Parshall soils are on similar positions. Grail soils are fine. Grassna soils are fine-silty. Parshall soils are coarse-loamy.
DRAINAGE AND PERMEABILITY: Well or moderately well drained. Runoff is negligible to high depending on the slope. Permeability is moderate. A seasonal high water table is at a depth of 3 to 6 feet at some time during the period of October through June in the moderately well drained phase.
USE AND VEGETATION: Most areas are cropped to spring wheat, oats, barley, and hay. Native vegetation is mid, tall, and short grasses such as western wheatgrass, green needlegrass, big bluestem and blue grama.
DISTRIBUTION AND EXTENT: Arnegard soils occur in western North Dakota, eastern Montana and northwestern South Dakota. The soils are extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: McKenzie County, North Dakota, 1937.
REMARKS: Diagnostic horizons and features recognized in this pedon are: mollic epipedon - the zone from the surface of the soil to a depth of 27 inches (Ap, A and Bw1 horizons); cambic horizon - the zone from 27 to 36 inches (Bw2 horizon).
Soil that formed in loess or similar silty materials were formerly included in the Arnegard series but are now placed in the Grassna series.