LOCATION SEAVERSON WYEstablished Series
TAXONOMIC CLASS: Loamy, mixed, superactive, calcareous, frigid, shallow Ustic Torriorthents
TYPICAL PEDON: Seaverson clay loam-rangeland. (Colors are for dry soil unless otherwise stated.)
A--0 to 3 inches; light olive brown (2.5Y 5/4) clay loam, olive brown (2.5Y 4/4) moist; weak coarse granular structure, surface 1/4 inch consists of a vesicular crust; slightly hard, firm, sticky and plastic; few fine and medium roots; strongly effervescent, lime disseminated; moderately alkaline (pH 8.4); clear smooth boundary. (1 to 5 inches thick)
Bk--3 to 10 inches; light olive brown (2.5 5/4) clay loam, olive brown (2.5Y 4/4) moist; massive, hard, very firm, sticky and plastic; few medium and coarse roots; violently effervescent, common fine and medium soft masses and filaments of lime; very strongly alkaline (pH 9.2); clear smooth boundary. (0 to 7 inches thick)
C--10 to 18 inches; light brownish gray (10YR 6/2) clay loam, light olive brown (2.5Y 5/6) moist; massive; hard, very firm, sticky and plastic; violently effervescent, lime disseminated and as few fine and medium soft masses; very strongly alkaline (pH 9.2); clear wavy boundary. (3 to 15 inches thick)
Cr--18 to 60 inches; soft, olive, sodic sandy shale interbedded with thin lenses of soft sodic saturated sandstone.
TYPE LOCATION: Carbon County, Wyoming; SE1/4, SE1/4 of sec. 29, T. 19 N., R. 91 W.
RANGE IN CHARACTERISTICS: Depth to soft bedrock and the paralithic contact ranges from about 4 to 20 inches. The mean annual soil temperature ranges from 40 to 47 degrees F., and the mean summer soil temperature ranges from 59 to 63 degrees F. These soils are not dry in all parts of the moisture control section three-forths of the time (cumulative) that the soil temperature at a depth of 20 inches is 41 degrees or higher. The particle size control section is a clay loam, sandy clay loam, or loam with 18 to 35 percent clay, 20 to 50 percent silt, and 20 to 52 percent sand of which over 15 percent is fine or coarser sand. The exchangeable sodium in the control section ranges from 15 to 30 percent when averaged. Soft shale fragments range from 0 to 35 percent throughout, but these fragments break down upon pretreatment.
The A horizon has hue of 2.5Y through 5YR, value of 4 through 6 dry, 3 through 5 moist, and chroma of 2 through 4. EC ranges from 2 to 8 mmhos. Exchangeable sodium ranges from 5 to 30 percent. Reaction is moderately through very strongly alkaline.
The Bk horizon has hue of 2.5Y through 5YR, value of 5 through 7 dry, 4 through 6 moist, and chroma of 2 through 4. Segregated lime is present and ranges from 8 to 14 percent. This horizon is either too thin or lime content too low to meet the requirements of a diagnostic calcic. EC ranges from 4 to 16 mmhos. ESP ranges from 15 to 30 when averaged. Salts more soluble than gypsum are common in some pedons. Reaction is strongly or very strongly alkaline.
The Cr horizon consists of soft, platy or massive clay shale interbedded with thin lenses of sandstone. The shale contains high amounts of calcium carbonates and lesser amounts of gypsum and more soluble salts. The soil-bedrock interface is considered to be a paralithic contact.
COMPETING SERIES: These are the Blackhall, Blazon, Byrnie, Cabbart, Niler, and Thermopolis series. All of these soils have less than 15 percent exchangeable sodium throughout. In addition, Blackhall and Byrnie soils have less than 18 percent clay in the control section.
GEOGRAPHIC SETTING: Seaverson soils are rolling uplands and occupy summits, shoulders, backslopes, and footslopes of hills and ridges. These soils formed in residuum and colluvial slopewash weathered from calcareous sodic shale. Slopes are predominantly complex and range from 3 to 45 percent. The climate is cool, semiarid with moist springs and dry summers. Elevations range from 5,300 to 7,500 feet. The mean annual precipitation ranges from 39 to 45 degrees F. The estimated frost-free season ranges from about 85 to 110 days depending upon elevation, aspect, and air drainage.
DRAINAGE AND PERMEABILITY: Well drained; medium or rapid runoff depending upon slope; very slow permeability.
USE AND VEGETATION: Rangeland and wildlife habitat. Native vegetation consists of birdfoot sagebrush, Gardner saltbush, thickspike wheatgrass, western wheatgrass, and Indian ricegrass.
DISTRIBUTION AND EXTENT: Cold basins of southern and western Wyoming. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Fremont County, Wyoming, East Part; 1985.
REMARKS:
The superactive cation exchange activity class was added in 03/2003 to the taxonomic classification by the National Soil Survey Center on request of the Reno MLRA office, without review of the soil series property data. The remainder of this document has not been updated.