LOCATION RUKO UTEstablished Series
TAXONOMIC CLASS: Clayey, smectitic, frigid, shallow Aridic Haplustepts
TYPICAL PEDON: Ruko clay loam--rangeland. (Colors are for air-dry soil unless otherwise stated.)
A--0 to 4 inches; pale brown (10YR 6/3) clay loam, brown (10YR 4/3) moist; moderate fine granular structure; soft, friable, slightly sticky and slightly plastic; common fine and very fine roots; many fine interstitial pores; 5 percent pebbles and 2 percent stones; strongly calcareous; moderately alkaline (pH 8.0); clear smooth boundary. (1 to 5 inches thick)
C1--4 to 7 inches; light gray (10YR 6/1) clay, gray (10YR 5/1) moist; weak medium subangular blocky structure; hard, firm, sticky and plastic; common fine, medium and coarse roots; few fine interstitial and tubular pores; strongly calcareous; moderately alkaline (pH 8.0); gradual wavy boundary. (3 to 6 inches thick.)
C2--7 to 19 inches; light gray (10YR 6/1) clay, gray (10YR 5/1) moist; weak medium subangular blocky structure; very hard, very firm, sticky and plastic; few very fine, medium and coarse roots; few fine interstitial and tubular pores; strongly calcareous; few fine faint white (10YR 8/1) carbonate segregations; moderately alkaline (pH 8.0); diffuse wavy boundary. (6 to 16 inches thick.)
Cr--19 inches; shale.
TYPE LOCATION: Kane County, Utah; Horse Hollow, NW 1/4 of sec. 11, T. 39 S., R. 4 W.
RANGE IN CHARACTERISTICS: The depth of soil material over shale ranges from 10 to 20 inches. The mean annual soil temperature is 44 to 47 degrees F., and the mean summer soil temperature is 59 to 64 degrees F. The soils are usually moist, but are dry for 90 cumulative days or more in 7 out of 10 years in some subhorizons between depths of 4 and 12 inches, but are not continuously dry in all parts between these depths for as long as 60 consecutive days. The clay content ranges from 35 to 45 percent in the particle-size control section.
The A horizon has hue of 10YR or 2.5Y, value of 6 or 7 dry, 4 or 5 moist and chroma of 2 to 4. It is slightly calcareous or strongly calcareous.
The C horizon has hue of 10YR to 2.5Y, value of 5 to 7 dry, 4 or 5 moist and chroma of 1 to 4. It is clay loam, silty clay loam, silty clay or clay. This horizon is strongly calcareous or very strongly calcareous.
COMPETING SERIES: These are the Norbert and Wayden series. Norbert soils have 50 to 60 percent clay in the particle-size control section. Wayden soils are slightly calcareous in the particle-size control section.
GEOGRAPHIC SETTING: Ruko soils are on sideslopes of hills and mountains at an elevation of 6,000 to 8,500 feet. Slope ranges from 20 to 70 percent. They formed in shale. The average annual precipitation is 12 to 20 inches and the freeze-free period ranges from 70 to 100 days. The mean annual temperature is 40 to 45 degrees F. and the average summer temperature is 59 to 64 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Frandsen, Podo and Syrett soils. Frandsen soils do not have a paralithic contact within 40 inches and are on benches. Podo soils have a lithic contact within 20 inches and are on similar positions. Syrett soils have a mollic epipedon, are not shallow and are on benches.
DRAINAGE AND PERMEABILITY: Well drained; rapid or very rapid runoff; very slow permeability.
USE AND VEGETATION: Wildlife habitat and some limited use for rangeland. The potential vegetation is pinyon pine, Utah juniper, Gambel oak, bitterbrush, curlleaf mountainmahogany, Indian ricegrass, slender wheatgrass, serviceberry, needleandthread grass, mutton bluegrass and some Douglas-fir, white fir and ponderosa pine.
DISTRIBUTION AND EXTENT: These soils are in the south-central part of Utah. They are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Kane County (Paunsaugunt Soil Survey Area), Utah, 1969.
REMARKS: These soils were formerly classified as Lithosols. Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from the surface of the soil to 4 inches (A horizon)
Orthent feature - a regular decrease in organic matter and a lack of diagnostic horizons below the ochric
Shallow feature - a paralithic contact at 19 inches (Cr horizon)