LOCATION ROCK RIVER WY+CO UTEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Ustic Calciargids
TYPICAL PEDON: Rock River sandy loam-rangeland. (Colors are for dry soil unless otherwise stated.)
A--0 to 2 inches; light brownish gray (10YR 6/2) sandy loam, dark yellowish brown (10YR 3/4) moist; hard crust that parts to weak fine granular; hard, very friable, slightly sticky and slightly plastic; many fine and medium roots; neutral (pH 7.2); clear smooth boundary. (2 to 6 inches thick)
Bt1--2 to 10 inches; yellowish brown (10YR 5/4) sandy clay loam, dark yellowish brown (10YR 4/4) moist; weak medium prismatic structure parting to moderate medium angular blocky; hard, firm sticky and plastic; few fine and many medium roots; continuous thin clay films on faces of peds; common mildly alkaline (pH 7.4); clear smooth boundary.
Bt2--10 to 19 inches; yellowish brown (10YR 5/4) sandy clay loam, dark yellowish brown (10YR 4/4) moist; moderate medium prismatic structure parting to moderate fine and medium angular blocky; hard, firm, sticky and plastic; few coarse roots; continuous, thin clay films on faces of peds; mildly alkaline (pH 7.6); clear smooth boundary. (The Bt horizon is 8 to 20 inches thick.)
Btk--19 to 26 inches; yellowish brown (10YR 5/4) sandy loam, dark yellowish brown (10YR 4/4) moist; weak medium angular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common thin clay films on faces of peds; strongly effervescent, lime as many fine and medium soft masses and threads; 10 percent pebbles 1/4 to 3/4 inch in diameter; moderately alkaline (pH 8.4); clear smooth boundary. (0 to 8 inches thick)
Bk--26 to 60 inches; light brownish gray (10YR 6/2) sandy loam, brown (10YR 5/3) moist; massive; soft, very friable, nonsticky and nonplastic; violently effervescent, lime as many soft masses; many fine soft masses and threads of secondary calcium carbonate; 15 percent lime-coated angular gravel 1/4 to 3/4 inch in diameter; moderately alkaline (pH 8.4).
TYPE LOCATION: Carbon County, Wyoming; near the E1/4 corner of sec. 27, T. 19 N., R. 91 W.
RANGE IN CHARACTERISTICS: Depth to continuous horizons of calcium carbonate accumulation is 13 to 30 inches. Depth to the base of the argillic horizon is 12 to 34 inches. The mean annual soil temperature ranges from 43 to 46 degrees F., and the mean summer soil temperature ranges from 59 to 65 degrees F. EC is less than 4 mmhos throughout. The rock fragments in the soil are less than 3/4 inch in diameter.
The A horizon has hue of 2.5Y through 7.5YR, value of 4 through 6 dry, 3 through 5 moist, and chroma of 2 through 4. Reaction is neutral through moderately alkaline.
The Bt horizon has hue of 2.5Y through 7.5YR, value of 4 through 6 dry, 4 or 5 moist, and chroma of 2 through 6. Texture is sandy clay loam or gravelly sandy clay loam, averaging 20 to 35 percent clay and has more than 35 percent fine or coarser sand. Rock fragments range from 0 to 25 percent pebbles. Reaction is neutral through moderately alkaline.
The Bk horizon has hue of 2.5Y through 7.5YR, value of 5 through 8 dry, 4 through 7 moist, and chroma of 2 through 6. Texture is sandy clay loam, sandy loam, or fine sandy loam modified with from 0 to 30 percent pebbles. Some pedons have textures of loamy sand or coarser below 40 inches. It has accumulation of secondary calcium carbonate that ranges from 1 through 14 percent. Reaction is moderately or strongly alkaline. Some pedons have a C horizon.
COMPETING SERIES: These are the
Alcova,
Almy,
Alogia,
Anchutz,
Antonito,
Bateson,
Bluerim,
Bonfri,
Cushool,
Cutback,
Diamondville,
Diamonkit,
Fluetsch,
Fonce,
Forelle,
Grubrob,
Harsha,
Hickey,
Maysprings(T),
Rawah,
Regnaps,
Satanka,
Stunner,
Stylite, Tafom(T), and
Wycolo series. Alcova and Bateson soils have very gravelly Bk and C horizons. Almy, Forelle, Regnaps, and Stunner soils have less than 35 percent fine or coarser sand in the B2t horizon. Alogia, Diamonkit, and Stylite soils have secondary accumulations of gypsum in the solum. Anchutz,
Fonce, Grubrob, Hickey, and Wycolo soils have diagnostic calcic horizons. Antonito and Grubrob soils have a lithic contact at depths of 20 to 40 inches. Bluerim, Bonfri, Cushool, Cutback, Diamondville, Diamonkit, Harsha, Rawah, Satanka and Wycolo soils have a paralithic contact at depths of 20 to 40 inches. Fluetsch soils are very similar but have a mean summer soil temperature of about 55 degrees F. Maysprings and
Taffom soils are non-calcareous above 40 inches.
GEOGRAPHIC SETTING: Rock River soils are on alluvial fans, fan aprons, benches, hillslopes, and toeslopes. The soils formed in material weathered from calcareous sandstone, eolian deposits, and residuum. Slopes are 0 to 25 percent. Elevation is 5,900 to 7,800 feet. The mean annual precipitation ranges from 10 to 14 inches of which about half falls as snow or rain in April, May, and early June. The mean annual temperature is about 41 to 45 degrees F., and the mean summer temperature is 59 to 63 degrees F. The frost-free season is about 75 to 110 days but varies according to aspect, elevation, and air drainage.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Alcova, Bluerim, Cushool, Diamondville, Forelle, and Satanka soils.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff, moderately permeable.
USE AND VEGETATION: Rangeland and wildlife habitat. In some areas these soils are irrigated for the production of small grains, alfalfa, and domestic grasses. Native vegetation is needleandthread, thickspike wheatgrass, big sagebrush, Sandberg bluegrass, and rabbitbrush.
DISTRIBUTION AND EXTENT: Cool basins in western and southern Wyoming and northwestern Colorado. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Saguache County area, Colorado; 1981.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon--0 to 2 inches(A)
Argillic horizon--2 to 26 inches (Bt1,Bt2,Btk)
Borollic feature--Organic carbon and temperature regime meet requirements for borollic.