LOCATION FARSON WYEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, frigid Ustic Calciargids
TYPICAL PEDON: Farson sandy loam-irrigated cropland. (Colors are for dry soil unless otherwise stated.)
Ap--0 to 8 inches; brown (10YR 5/3) sandy loam, dark grayish brown (10YR 4/2) moist; weak medium clods; soft, very friable, slightly sticky and nonplastic; common, fine, and very fine roots; slightly alkaline (pH 7.4); abrupt smooth boundary. (5 to 10 inches thick for the Ap or A horizon)
Bt--8 to 17 inches; brown (10YR 5/3) sandy loam, brown (10YR 4/3) moist; moderate coarse prismatic structure parting to weak medium subangular blocky; hard, friable, moderately sticky and slightly plastic; common, very fine, and fine roots; common thin clay films on faces of peds; slightly alkaline (pH 7.4); clear wavy boundary. (5 to 13 inches thick)
Bk1--17 to 19 inches; pale brown (10YR 6/3) gravelly sandy loam, brown (10YR 4/3) moist; hard, very friable, slightly sticky and nonplastic; common, fine, and very fine roots; strongly effervescent, 8 percent calcium carbonate equivalent, lime disseminated and as few soft masses; 20 percent fine gravel; moderately alkaline (pH 7.9); clear wavy boundary. (2 to 6 inches thick)
2Bk2--19 to 42 inches; light brownish gray (2.5Y 6/2) gravelly sand stratified with thin lenses of pale brown gravelly loamy fine sand 1/4 to 3 inches, grayish brown (2.5Y 5/2) moist; single grain, loose; few fine and very fine roots; slightly effervescent, 10 percent calcium carbonate equivalent, lime disseminated and as few soft masses; 20 percent gravel; moderately alkaline (pH 8.0); abrupt wavy boundary. (20 to 40 inches thick)
3C--42 to 60 inches; light brownish gray (2.5Y 6/2) coarse sand, olive gray (5Y 5/2) moist; single grain, loose; slightly effervescent, lime disseminated; moderately alkaline (pH 8.0).
TYPE LOCATION: Sweetwater County, Wyoming; about 3.5 miles NE of Farson; 900 feet east and 100 feet north of the SW corner of sec. 18, T. 25 N., R. 105 W; Eden Reservoir West USGS quad; lat. 42 degrees 08 minutes 08 seconds N. and long. 109 degrees 23 minutes 24 seconds W., NAD 83.
RANGE IN CHARACTERISTICS:
Soil moisture: aridic regime, ustic subclass.
Depth to the base of the argillic horizon and to contrasting gravelly sand or coarse sand ranges from 10 to 20 inches.
Depth to bedrock is typically greater than 60 inches but can range up to 40 inches on upper pediment slopes.
The A and Bt horizons are typically leached free of carbonates. However, the lower Bt may be calcareous in some pedons.
Mean annual soil temperature: 43 to 47 degrees F.
Mean summer temperature: about 59 to 64 degrees F.
A horizon
Hue: 10YR or 2.5Y
Value: 4 through 6 dry, 3 or 4 moist
Chroma: 2 or 3
EC: 0 to 2 mmhos
Reaction: neutral or slightly alkaline.
An Ap horizon, when present, has the same range as the A horizon.
Bt horizon
Hue: 7.5YR through 2.5Y
Value: 4 through 6 dry, 3 through 5 moist
Chroma: 2 through 4
Texture: sandy loam or fine sandy loam
Clay content: 10 to 18 percent
Content of fine and coarser sand: more than 50 percent
Coarse fragment content: 0 to 15 percent rounded gravel
EC: 0 to 2 mmhos.
Reaction: neutral or slightly alkaline
Bk horizon
Hue: 10YR or 2.5Y
Value: 5 through 7 dry, 4 or 5 moist
Chroma: 2 through 4
Texture, fine earth fraction: sandy loam or fine sandy loam
Noncarbonate clay content: 5 to 12 percent
Coarse fragment content: 0 to 20 percent gravel
Calcium carbonate equivalent: 8 to 22 percent
EC: 0 to 4 mmhos
Reaction: moderately alkaline or strongly alkaline
2Bk horizon
Hue: 10YR or 2.5Y
Value: 5 through 7 dry, 5 or 6 moist
Chroma: 2 through 4
Texture: sand, loamy sand, or gravelly sand
Noncarbonate clay content: 0 to 5 percent
Gravel content: 0 to 35 percent rounded gravel
Calcium carbonate equivalent: 8 to 22 percent
Reaction: moderately alkaline or strongly alkaline
3C horizon (when present)
Has the same range in characteristics as the 2Bk horizons except that they lack the increase in pedogenetic lime
Texture: coarse sand or sand.
Autogenetic carbonates range from 0 to 8 percent.
COMPETING SERIES: These are the Cotha, Elk Mountain, Means, Ryan Park, and Ryark series. Cotha, Elk Mountain, and Means soils have bedrock at 20 to 40 inches. Ryan Park soils have sandy loam, loamy fine sand, or loamy sand substrata. Ryark soils are noncalcareous throughout.
GEOGRAPHIC SETTING: Farson soils are on nearly level to sloping relict fan aprons and fan pediments. They formed in stratified, calcareous alluvium derived from sandstone and other coarse sediments. Slopes are 0 to 10 percent and simple. Elevations are 6,200 to 7,200 feet. The mean annual precipitation ranges from 7 to 13 inches with about half falling as snow or less commonly rain in April, May, and early June. The mean annual temperature ranges from 34 to 40 degrees F. The frost-free period is estimated to range from 60 to 85 days depending upon elevation, aspect, and air drainage.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bosler and Vonet soils. Bosler soils have more than 18 percent clay in the argillic horizon and have a diagnostic contrasting particle-size control section. Vonet soils are sandy throughout and have cambic horizons. These soils occur in the same relative positions as the Farson soils, but micro topography accounts for the difference in development.
DRAINAGE AND PERMEABILITY: Well drained; low to medium runoff depending upon surface texture and slope; permeability in the upper part is moderate and is rapid in the substratum. When irrigated, these soils may develop a water table at depths below 5 feet due to perched water on the underlying shale beds.
USE AND VEGETATION: Rangeland, irrigated hayland, pasture, and small grain and wildlife habitat. Native vegetation consists of needleandthread, Indian ricegrass, wheatgrasses, Wyoming big sagebrush, and low rabbitbrush.
DISTRIBUTION AND EXTENT: Mapped areas are of small extent in southwestern Wyoming but are expected to be moderate when recorrelation is done on public land areas. MLRA 34A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Sweetwater County, Wyoming, Eden Valley Area; 1985.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: from 0 to 8 inches. (Ap horizon)
Argillic horizon: from 8 to 17 inches. (Bt horizon)
Calcic horizon: from 17 to 42 inches. (Bk1, 2Bk2 horizons)
Particle-size control section: The zone from 8 to 17 inches. (entire argillic horizon)
Series control section: The zone from 0 to 60 inches
Taxonomic version: Classified according to Keys to Soil Taxonomy, Tenth Edition, 2006.