LOCATION HEIL ND+MT SDEstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Typic Natraquerts
TYPICAL PEDON: Heil silty clay in native grassland. (Colors are for moist soil unless otherwise stated)
E--0 to 3 inches; dark gray (10YR 4/1) silty clay, light gray (10YR 6/1) dry; common fine distinct brown (10YR 5/3) and dark brown (10YR 4/3) redox concentrations; moderate fine subangular blocky and weak thin platy structure; firm; many roots and fine pores; neutral; abrupt wavy boundary. (1 to 4 inches thick)
Btn--3 to 7 inches; very dark gray (2.5Y 3/1) silty clay, gray (2.5Y 5/1) dry; strong coarse and medium columnar structure parting to strong coarse medium and fine angular blocky; extremely hard, very firm; roots in cracks; few pores; slightly alkaline; gradual smooth boundary.
Btng--7 to 24 inches; very dark gray (5Y 3/1) silty clay, gray (5Y 5/1) dry; strong very coarse prismatic structure parting to strong coarse and medium angular blocky; extremely hard, very firm; few roots; surface of peds have a glossy appearance when moist; few tongues of E (5Y 6/1) dry; moderately alkaline; gradual wavy boundary. (Combined Btn horizons 6 to 38 inches thick)
Bg--24 to 38 inches; dark gray (5Y 4/1) silty clay, light gray (5Y 6/1) dry; moderate coarse angular blocky structure; extremely hard, very firm; strong effervescence; moderately alkaline; gradual wavy boundary. (0 to 17 inches thick)
Byg1--38 to 44 inches; dark gray (5Y 4/1) silty clay, light gray (5Y 6/1) dry; weak coarse and fine angular blocky structure; very firm, few fine gypsum crystals; strong effervescence; moderately alkaline; diffuse boundary.
Byg2--44 to 52 inches; olive (5Y 4/3) silty clay, pale olive (5Y 6/3) dry; weak coarse subangular blocky structure; very firm; common gypsum crystals; strong effervescence; strongly alkaline; gradual boundary. (Combined Byg horizons 0 to 30 inches thick)
Cg--52 to 60 inches; olive (5Y 5/4) silty clay, pale olive (5Y 6/3) dry; many strong brown (7.5YR 5/6) and yellowish brown (10YR 5/6) redox concentrations and gray (5Y 5/1) redox depletions; massive; few large white masses of carbonates; strong effervescence; strongly alkaline.
TYPE LOCATION: Slope County, North Dakota; about 6 miles east and 2 miles north of Amidon; 650 feet west and 20 feet south of the northeast corner, sec. 14, T. 135 N., R. 100 W.
RANGE IN CHARACTERISTICS: Thickness of the mollic epipedon typically is less than 30 inches, but ranges from 7 to 45 inches. Depth to carbonates range from 12 to 40 inches. The A, E and upper Btn horizons are free of carbonates. Some pedons have an A horizon 1 to 3 inches thick. Total thickness of A and E horizons ranges from 1 to 4 inches. Visible salts are in the Bg and Cg horizons of some pedons.
The E horizon has hue of 10YR, 2.5Y or 5Y, value of 2 to 5 moist and 4 to 8 dry, and chroma of 1 or 2. It is silt loam, silty clay loam or silty clay. It is moderately acid to neutral.
The Btn horizon has hue of 10YR, 2.5Y or 5Y, value of 2 to 4 and 4 to 6 dry, and chroma of 1 or 2. It is silty clay or clay averaging 45 to 60 percent clay. It is slightly acid to strongly alkaline. Some pedons have a Btkn, Btnz or Btny horizon.
The Bg and Byg horizons have hue of 2.5Y or 5Y, value of 3 to 5 and 4 to 7 dry, and chroma of 1 to 3. They are silty clay, clay, silty clay loam or clay loam. It is slightly alkaline to strongly alkaline. Some pedons have a Bk, Bky, Bkz, Bkzg or Bz horizon.
The Cg horizon has hue of 2.5Y or 5Y, value of 3 to 5 and 5 to 7 dry, and chroma of 1 to 4. It has textures similar to the Bg and Byg horizons. It is slightly alkaline to strongly alkaline. Soft bedrock or loam or clay loam till is below depths of 40 inches in some pedons. Some pedons have 1 to 5 percent gravel in the C horizon.
COMPETING SERIES: This is the Ryan series and the Harriet and Ranslo series as previously classified. Ryan soils have carbonates within depths of 10 inches and are on terraces and glacial lake plains. Harriet soils have carbonates within depths of 11 inches and formed in stratified alluvium. Ranslo soils have a combined A and E horizon thickness of 5 inches or more.
GEOGRAPHIC SETTING: Heil soils are in level shallow lake basins and flat enclosed uplands depressions. Slope ranges from 0 to 1 percent. The soils formed in clayey calcareous alluvium. Mean annual air temperature ranges from 34 to 45 degrees F, and mean annual precipitation from 12 to 18 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: This is the competing Harriet soil and the Amor, Cabba, Dimmick, McKenzie, Morton, Reeder, Regent, Sen, Williams and Zahl soils. Harriet soils are on floodplains and low terraces. Dimmick and McKenzie soils are in the same basins adjacent to the Heil soils. These soils do not have natric horizons. In addition, McKenzie soils do not have mollic epipedons. Amor, Cabba, Morton, Reeder, Regent, Sen, Williams and Zahl soils are on higher positions on the landscape. They are well drained soils and do not have natric horizons.
DRAINAGE AND PERMEABILITY: Poorly drained. Runoff is ponded after heavy rains and melt waters from snow. Permeability is very slow. A seasonal high water table is at a depth of 1.0 foot above the surface to 1.5 foot below the surface at some time during the period March through July.
USE AND VEGETATION: Most of these soils are used for rangeland and hay. Vegetation is mixed grasses and sedges: mainly western wheatgrass, prairie cordgrass and common spike sedge.
DISTRIBUTION AND EXTENT: Western North Dakota, eastern Montana, and northwestern South Dakota. The soil is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Bowman County, North Dakota, 1969.
REMARKS: The site will be redescribed in the future to document the Vertisol criteria.
Diagnostic horizons and features recognized in this pedon are: mollic epipedon - the zone from the surface of the soil to a depth of 24 inches (E, Btn and Btng horizons); natric horizon - the zone from 3 to 24 inches (Btn and Btng horizons); features associated with wetness - chroma of 1 throughout the upper meter and redox concentrations at the surface (E horizon).