LOCATION HIGGINS SD+WYEstablished Series
TAXONOMIC CLASS: Coarse-silty, gypsic, mesic Typic Endoaquepts
TYPICAL PEDON: Higgins silt loam - on a convex 1 percent slope in native grass. When described the soil was wet to the surface and had a water table at 18 inches. (Colors are for moist soil unless otherwise stated.)
A--0 to 3 inches; dark grayish brown (10YR 4/2) silt loam; light gray (10YR 7/2) dry; weak fine granular structure; soft, very friable; many fine and medium roots; violent effervescence; slightly alkaline; clear smooth boundary. (2 to 5 inches thick)
Bky1--3 to 9 inches; light brownish gray (2.5Y 6/2) silt; white (2.5Y 8/1) dry; few fine distinct yellowish brown (10YR 5/6) mottles; weak medium and coarse subangular blocky structure; slightly hard, very friable; common fine roots; many very fine gypsum crystals; violent effervescence; slightly alkaline; gradual smooth boundary.
Bky2--9 to 25 inches; light brownish gray (2.5Y 6/2) silt; white (2.5Y 8/1) dry; few fine distinct yellowish brown (10YR 5/6) mottles; weak medium and coarse subangular blocky structure; slightly hard, very friable; common fine roots; many very fine gypsum crystals; violent effervescence; slightly alkaline; gradual smooth boundary.
Bky3--25 to 35 inches; light gray (2.5Y 7/2) silt; white (2.5Y 8/1) dry; few fine faint yellowish brown (10YR 5/6) mottles; weak medium and coarse subangular blocky structure; slightly hard, very friable; few fine roots; many fine gypsum crystals; violent effervescence; slightly alkaline; gradual smooth boundary. (Combined Bky horizons is 10 to 40 inches thick.)
C--35 to 60 inches; light brownish gray (2.5Y 6/2) with streaks of gray (N 6/0) silt; light gray (2.5Y 7/2 and N 7/0) dry; massive; slightly hard; very friable; many fine gypsum crystals; slightly alkaline; strong effervescence; gradual smooth boundary.
TYPE LOCATION: Lawrence County, South Dakota; about 7 miles west and 4 miles north of Spearfish; 2400 feet west and 750 feet north of the southeast corner of sec. 16, T. 7 N., R. 1 E.
RANGE IN CHARACTERISTICS: These soils typically have free carbonate at the surface, but in some pedons, the upper 5 inches are leached. The percentage of carbonate and gypsum ranges from 40 to 60 percent in the Bky horizon.
The A horizon has hue of 7.5YR, 10YR, or 2.5Y; value of 3 to 6 and 5 to 7 dry; and chroma of 1 or 2. It typically is silt or silt loam, but some pedons are loam. It is neutral to moderately alkaline.
The Bky horizon has hue of 5YR, 7.5YR, 10YR, or 2.5Y; value of 5 to 7 and 6 to 8; and chroma of 1 or 2. Chroma ranges to 8 in some pedons. It has few or common distinct high chroma mottles in the upper part and faint and distinct mottles in the lower part. It is silt or silt loam. It is slightly alkaline or moderately alkaline and has a calcium carbonate equivalent of 10 to 20 percent.
The C horizon has hue of 5YR, 7.5YR, 10YR, or 2.5Y; value of 5 to 7 and 6 to 8 dry; and chroma of 0 to 2. In some pedons chroma ranges to 8, which is inherent to nearby reddish sediments. It is silt or silt loam and neutral to moderately alkaline.
COMPETING SERIES: There are no other series in this family.
GEOGRAPHIC SETTING: Higgins soils are on nearly level alluvial fans and bottom lands. Slope gradient ranges from 0 to 3 percent. These soils formed in stratified silty alluvium containing much gypsum. Mean annual temperature ranges from 43 to 48 degrees F, and precipitation ranges from 14 to 20 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Barnum, Nevee, and Swint soils. The Barnum and Swint soils are on similar landscapes, and the Nevee soils are above the Higgins soils. All these soils do not have an aquic moisture regime. In addition, Barnum and Swint soils are fine-loamy and Swint soils have a mollic epipedon.
DRAINAGE AND PERMEABILITY: Very poorly drained. Runoff is slow. Permeability is moderate. The water table is at 0 to 1 foot except during late summer and fall or during drought years.
USE AND VEGETATION: Rangeland. Native vegetation includes cordgrass, big bluestem, Indiangrass, switchgrass, and saltgrass.
DISTRIBUTION AND EXTENT: The footslopes of the Black Hills in western South Dakota and northeastern Wyoming. The series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Lawrence County, South Dakota, 1977.
REMARKS: Diagnostic horizons and features recognized in this pedon are: ochric epipedon - the zone from the surface of the soil to a depth of about 3 inches (A horizon); gypsic horizon - the zone from about 3 to 35 inches (Bky1, Bky2, Bky3 horizons).