LOCATION RAWAH COEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive Ustic Argicryids
TYPICAL PEDON: Rawah loam - grassland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 4 inches; brown (7.5YR 5/2) loam, dark brown (7.5YR 3/2) moist; strong fine granular structure; soft, very friable, slightly sticky, slightly plastic; 5 percent gravel, mostly on the surface; mildly alkaline (pH 7.6); clear smooth boundary. (0 to 4 inches thick)
B1--4 to 7 inches; reddish brown (2.5YR 5/4) loam, dark reddish brown (2.5YR 2/3) moist moderate fine subangular blocky structure that parts to fine granules; slightly hard, very friable, slightly sticky, slightly plastic; glossy patches on some faces of peds; mildly alkaline (pH 7.6); clear smooth boundary. (0 to 4 inches thick)
B2t--7 to 15 inches; reddish brown (2.5YR 5/5) light clay loam, reddish brown (2.5YR 4/5) moist; moderate medium prismatic structure that parts to medium subangular blocks; slightly hard, very friable, slightly sticky, slightly plastic; peds are very hard, firm; wax-like patches on faces of peds and in root channels and pores; mildly alkaline (pH 7.6); clear smooth boundary. (5 to 22 inches thick)
B3ca--15 to 20 inches; light reddish brown (2.5YR 6/5) heavy loam, reddish brown (2.5YR 5/d) moist moderate medium subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic; peds are very hard, friable; few thin glossy patches on faces of peds; visible secondary calcium carbonate as concretions; calcareous; moderately alkaline (pH 8.0); gradual wavy boundary. (3 to 6 inches thick)
Clca--20 to 30 inches; light reddish brown (2.5YR 6/4) loam, reddish brown (2.5YR 5/4) moist; massive hard, very friable, slightly sticky, slightly plastic; visible secondary calcium carbonate as concretions and in thin seams and streaks; calcareous; moderately alkaline (pH 8.4); diffuse wavy boundary. (5 to 25 inches thick)
IIC2--30 to 60 inches; calcareous redbed shales and siltstones.
TYPE LOCATION: Jackson County, Colorado; approximately 240 feet east N1/4 corner Sec. 4, T. 9 N., R. 81 W.
RANGE IN CHARACTERISTICS: Mean annual soil temperature is about 42 degrees F., and mean summer soil temperature is about 56 degrees F. Depth to uniformly calcareous material ranges from 8 to 30 inches. Depth to the paralithic contact ranges from 20 to 40 inches. Depth to the base of the argillic horizon ranges from 12 to 30 inches. Depth to continuous subhorizons of visible secondary carbonate and/or sulfate ranges from 10 to 35 inches, but such horizons are not strong enough to qualify as calcic or gypsic horizons. ESP either remains constant or increases with depth, ranging from 0 to 15 percent in the solum but exceeds 15 percent in the Cca horizon of some pedons. Rock fragments range from 0 to 15 percent by volume in a major part of the solum and C horizon above the paralithic contact and they are mainly 1/4 to 10 inches in diameter.
The A horizon has hue of 1OYR through 2.5YR, value of 5 through 7 dry, 4 through 6 moist, and chroma of 1 through 4. It is neutral or mildly alkaline.
The B2t horizon has hue of 5YR through 10R, value of 5 through 7 dry, 4 through 6 moist, and chroma of 1 through 6. It is typically loam or clay loam, but averages 18 to 35 percent clay, 20 to 55 percent silt, and 20 to 50 percent sand with less than 35 percent fine or coarser sand. This horizon ranges from neutral to moderately alkaline.
The Cca horizon has hue of 5YR through 10R. It is moderately or strongly alkaline and has about 3 to 14 percent calcium carbonate equivalent.
COMPETING SERIES: These are the Almy, Cushool, Diamondville, Fluetsch, Forelle, Heflin, Rock River, Satanka, and Stunner series. Almy, Fluetsch, Forelle, Heflin, Rock River, and Stunner soils lack a paralithic contact at depths of less than 40 inches. Cushool and Satanka soils have lithochromic hue no redder than 7.5YR.
GEOGRAPHIC SETTING: Rawah soils are on moderately to steeply sloping upland hills, ridges, and mountainsides. Slopes range from 2 to about 30 percent. At the type location these soils occur at elevations in excess of 8,000 feet. They formed in medium to moderately fine textured calcareous reddish brown sediments weathered from underlying redbed shales and sandstones. Mean annual precipitation is 10 inches with peak periods of precipitation during the spring and early summer. The average annual temperature is 38 degrees F., and the average summer temperature is 56 degrees F.
GEORAPHICALLY ASSOCIATED SOILS: These are the Bosler soils and the competing Forelle soils. Bosler soils lack a paralithic contact at depths of less than 40 inches.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderate permeability.
USE AND VEGETATION: These soils are used mainly as native pastureland. Principal native vegetation is big sagebrush, Thurber
fescue, and Idaho fescue.
DISTRIBUTION AND EXTENT: High mountain valleys of north-central Colorado. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Jackson County, Colorado, 1973.
REMARKS: Last updated by the state 11/73.