LOCATION BONJEA WYEstablished Series
TAXONOMIC CLASS: Loamy, mixed, superactive, frigid Lithic Argiustolls
TYPICAL PEDON: Bonjea sandy loam on a southeast facing slope of 8 percent-rangeland. (Colors are for air-dry soil unless otherwise stated.)
A--0 to 4 inches; brown (10YR 4/3) sandy loam, dark brown (10YR 3/3) moist; weak fine and medium granular structure; soft, very friable, nonsticky and nonplastic; common fine and medium roots; 5 percent fine pebbles; neutral (pH 7.0); abrupt smooth boundary. (3 to 6 inches thick)
Bt1--4 to 10 inches; brown (10YR 4/3) sandy clay loam, dark brown (10YR 3/3) moist; moderate coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common fine and medium roots; many faint clay films on faces of peds; 5 percent fine pebbles; neutral (pH 7.0); clear smooth boundary.
Bt2--10 to 15 inches; yellowish brown (10YR 5/6) gravelly sandy clay loam, dark yellowish brown (10YR 4/6) moist; moderate fine and medium subangular structure; hard, friable, slightly sticky and slightly plastic; common medium roots; many distinct clay films on faces of peds; 20 percent fine and coarse pebbles; neutral (pH 7.0); abrupt broken boundary. (Combined thickness of the Bt horizon is 7 to 14 inches.)
R--15 inches; granite bedrock.
TYPE LOCATION: Albany County, Wyoming; about 21 miles northeast of Laramie; approximately 1,500 feet south and 2,300 feet east of the NW corner of Sec. 10, T. 18 N., R. 71 W.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature: 40 to 47 degrees F.
Mean summer soil temperature: 60 to 68 degrees F
Depth to the lithic contact: 10 to 20 inches to granite
Thickness of the mollic epipedon: 7 to 15 inches
Depth to the base of the argillic horizon: 10 to 20 inches
Reaction throughout the profile: neutral or slightly alkaline
A horizon:
Hue: 7.5YR or 10YR
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 2 or 3 dry and moist
Clay content: 10 to 20 percent
Rock fragments: 0 to 5 percent fine pebbles
Bt horizon:
Hue: 7.5YR through 2.5Y
Value: 4 or 5 dry, 3 or 4 moist
Chroma: 3 through 6 dry or moist
Texture: gravelly sandy clay loam or sandy clay loam with more than 35 percent fine sand or coarser
Rock fragments: average from 10 to 35 percent fine or coarse pebbles, coarse pebble content commonly increases immediately above the lithic contact
Clay content: 20 to 35 percent
The Bt horizon typically extends to the lithic contact, but a thin C horizon occurs in some pedons.
COMPETING SERIES: These are the Beenom, Beje, Berland, Cedric, Coni, Connieo, Kiln, and Viewpoint series.
Beenom,
Beje, Berland: lack the coarse granitic sands and have sandstone or shale bedrock and rock fragments
Cedric: accumulations of secondary calcium carbonate
Coni: more moist in July and August
Connieo: paralithic contact overlying the lithic contact
Kiln: formed in limestone and have limestone rock fragments
Viewpoint: formed in basalt and have basalt-breccia rock fragments
GEOGRAPHIC SETTING:
Parent material: slope alluvium and colluvium over residuum from granite
Landform: foothills and gently sloping to steep mountainsides
Slopes: 3 to 60 percent
Elevation: 6,000 to 7,800 feet
Mean annual precipitation: about 17 inches and ranges from 15 to 19 inches with about half falling as snow and rain in April, May, and early June
Mean annual temperature: 40 to 45 degrees F.
Frost- free season: 85 to 110 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Boyle, Dalecreek, and Lininger soils. Boyle soils occupy similar positions on the landscape but have loamy-skeletal control sections over weathered granite. Dalecreek soils are on floodplains and valley fills and are more than 40 inches deep without an argillic horizon. Lininger soils occupy similar positions on the landscape but are more than 20 inches deep over weathered granite.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff on lesser slopes and rapid runoff on steeper slopes; moderate permeability.
USE AND VEGETATION: These soils are used for rangeland and wildlife habitat. Vegetation is mostly bluebunch wheatgrass, slimstem muhly, prairie junegrass, and threetip sagebrush.
DISTRIBUTION AND EXTENT: Mountainous areas of southeastern Wyoming. The series is of moderate extent, about 15,000 acres.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Albany County Area, Wyoming; 1991. The name is coined.
REMARKS: Diagnostic horizons and features recognized in this pedon are: Mollic epipedon - 0 to 10 inches (A and Bt1 horizons); Argillic horizon - 4 to 15 inches (Bt horizons); Lithic contact - the contact with bedrock at 15 inches (R).
Classification was changed from Lithic Argiboroll to superactive, frigid Lithic Argiustolls 2/1999.
Taxonomic version: Eighth Edition, 1998.