LOCATION VONASON WYEstablished Series
TAXONOMIC CLASS: Sandy, mixed, frigid Ustic Haplocambids
TYPICAL PEDON: Vonason loamy sand-rangeland. (Colors are for dry soil unless otherwise stated.)
A--0 to 3 inches; grayish brown (10YR 5/2) loamy sand, dark brown (10YR 4/3) moist; weak thin platy structure parting to weak fine granular; soft, very friable, nonsticky and nonplastic; common very fine and fine roots; mildly alkaline (pH 7.6); clear wavy boundary. (2 to 6 inches thick)
Bw--3 to 19 inches; brown (10YR 5/3) sandy loam, dark brown (10YR 4/3) moist; weak coarse prismatic structure parting to weak coarse subangular blocky; soft, very friable, slightly sticky and nonplastic; common very fine, fine, and medium roots; mildly alkaline (pH 7.6); clear wavy boundary. (8 to 25 inches thick)
Bk--19 to 29 inches; light brownish gray (2.5Y 6/2) gravelly loamy sand, grayish brown (2.5Y 5/2) moist; massive; loose, very friable, nonsticky and nonplastic; few fine roots; violently effervescent, calcium carbonate disseminated and as white coatings on pebbles; 30 percent pebbles; moderately alkaline (pH 8.0); gradual wavy boundary. (10 to 28 inches thick)
C--29 to 60 inches; light brownish gray (2.5Y 6/2) gravelly loamy sand, dark grayish brown (2.5Y 4/2) moist; single grain, loose, nonsticky and nonplastic; few fine roots; strongly effervescent, calcium carbonate disseminated, 27 percent pebbles; moderately alkaline (pH 8.0).
TYPE LOCATION: Sweetwater County, Wyoming; 1,300 feet east and 950 feet north of SW corner of sec. 35, T. 24 N., R. 106 W. About 3.5 miles southeast of Eden, Wyoming.
RANGE IN CHARACTERISTICS: Depth to the base of the cambic horizon and free carbonates ranges from 11 to 28 inches. The mean annual soil temperature ranges from 43 to 47 degrees F., and the mean summer soil temperature ranges from 59 to 63 degrees F. Where irrigated, summer temperatures may range down to 57 degrees F. The particle size control section is complex with the cambic horizon being coarse-loamy and the majority of the Bk and C horizons being sandy. When averaged, the control section is sandy. EC is 2 mmhos or less throughout. Depth to bedrock exceeds 60 inches.
The A horizon has value of 5 or 6 dry, 3 or 4 moist, and chroma of 2 or 3. Reaction is neutral or mildly alkaline.
The Bw horizon has chroma of 3 or 4. Texture is sandy loam with 7 to 14 percent clay. This horizon is noncalcareous throughout. Reaction is neutral or mildly alkaline.
The Bk horizon has hue of 10YR or 2.5Y, value of 6 or 7 dry, 4 through 6 moist, and chroma of 2 or 3. Texture is loamy sand, gravelly loamy sand, and sand with 2 to 7 percent clay and 0 to 20 percent fine rounded pebbles. Carbonates range from 2 to 5 percent and are mostly disseminated with very thin powdery coatings on some pebbles. Reaction is mildly alkaline (pH 7.8) through moderately alkaline.
The C horizon has hue of 10YR or 2.5Y, value of 5 through 7 dry, 4 through 6 moist, and chroma of 2 through 4. Texture is loamy sand, gravelly loamy sand, or sand with 2 to 7 percent clay. Carbonates are disseminated and range from 1 to 4 percent. Reaction is mildly alkaline (pH 7.6) through moderately alkaline.
COMPETING SERIES: There are no other soils recognized in this class.
GEOGRAPHIC SETTING: Vonason soils are on nearly level to sloping relict fan piedmonts, fan aprons, and terraces. The soils formed in coarse textured, mixed alluvium. Slopes are 0 to 10 percent. Elevation is 6,500 to 7,200 feet. The mean annual precipitation is about 7 to 10 inches, and the mean annual temperature is 37 to 42 degrees F. The frost-free season is estimated to be about 60 to 90 days depending upon elevation, aspect, and air drainage.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cotopaxi, Farson, and Space City series. Cotopaxi and Space City soils are psamments and have no development. Farson soils have an argillic horizon.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; moderately rapid permeability upper part and very rapid in the subsoil.
USE AND VEGETATION: Rangeland, wildlife habitat, and irrigated cropland. Native vegetation is big sagebrush, rubber rabbitbrush, thickspike wheatgrass, needleandthread, and Indian ricegrass.
DISTRIBUTION AND EXTENT: Southwestern Wyoming. These soils are of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Eden Valley Area, Sweetwater County, Wyoming; 1985.