LOCATION OBRAY UT+ID OREstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Typic Haploxererts
TYPICAL PEDON: Obray silty clay - cultivated
(Colors are for dry soil unless otherwise noted.)
Ap--0 to 7 inches; dark grayish brown (lOYR 4/2) silty slay, very dark grayish brown (lOYR 3/2) moist; weak medium subangular blocky structure that parts to weak fine and medium granular structure; very hard, firm, sticky, very plastic, few medium and fine root; common fine pores; slightly acid (pH 6.4); clear smooth boundary. (5 to 7 inches thick)
A12--7 to 22 inches; brown (7.5YR 4/2) silty clay, dark brown (7.5YR 3/3) moist; moderate medium priamatic structure that parts to moderate medium and fine angular blocky structure; extremely hard, very firm, very sticky, very plastic; few fine root; few fine pores; common slickensides; slightly acid (pH 6.3); gradual wavy boundary. (10 to 43 inches thick)
A13--22 to 32 inches; brown (7.5YR 5/3) silty clay, dark brown (7.5YR 3/3) moist; moderate medium prismatic structure that parts to moderate medium angular blocky structure; extremely hard, very firm, very sticky, very plastic; few fine roots; few fine pores; common slickensides; neutral (pH 6.9); clear irregular boundary. (O to 19 inches thick)
C1--32 to 39 inches; brown (7.5YR 5/4) silty clay, dark brown (7.5YR 3/3) moist; moderate medium prismatic structure that parts to moderate medium angular blocky structure; extremely hard, very firm, very sticky, very plastic; few fine roots; few fine pores; common slickenslides; slightly calcareous; neutral (pH 7.2); gradual irregular boundary.
(O to 7 inches thick)
C2ca--39 to 52 inches; brown (7.5YR 5/4) silty clay, brown (7.5YR 5/3) moist; weak medium prismatic structure that parts to moderate medium angular blocky structure; very hard, very firm, sticky, very plastic; moderately calcareous; mildly alkaline (pH 7.6); gradual irregular boundary. (13 to 16 inches thick)
C2ca--52 to-60 inches; very pale brown (lOYR 7/3) silty clay loam, light yellowish brown (lOYR 6/4) moist; massive; hard, firm, sticky, plastic; strongly calcareous; mildly alkaline (pH 7.7).
TYPE LOCATION: Cache County, Utah; about 4 miles south and 1 mile east of Avon; 900 feet west of the southeast corner of the northwest 1/4 section 25, T.9N, R.lE.
RANGE IN CHARACTERISTICS: The mollic epipedon is 31 to 45 inches thick. Depth to strongly calcareous material is 45 to 65 inches. The surface 30 to 40 inches are noncalcareous and the 30 to 65 inch depths are noncalcareous to moderately calcareous. The average annual soil temperature is 44 degrees to 46 degrees F., and the average temperature at about 20 inches depth is 65 degrees to 68 degrees F. The C.E.C./clay ratio is 0.7 to 0.95. Cracks 1/2 to 2 inches wide extending to depths of 40 inches or more occur when the soils are dry. The cracks open and close once each year and remain open for 60 consecutive days or more in 7 out of 10 years. In the uncultivated areas, gilgai micro-relief is evident.
The Al horizon has hue of lOYR to 7.5YR, value of 3 through 5 dry and 2 or 3 moist, and chroma of 2 or 3. It has weak to strong medium subangular blocky structure that parts to weak fine or medium granules in the upper portion and moderate to strong prismatic structure that parts to moderate medium and fine subangular blocks in the lower part. It is slightly to medium acid. It has common to many slickensides.
The C horizon has hue of lOYR or 7.5YR, value of 5 through 7 dry, and 3 through 6 moist, and chroma of 2 throgh 4. It is usually silty clay or clay, ranging to heavy silty clay loam or heavy clay loam. It has weak to moderate prismatic structure or is massive. It is medium acid to mildly alkaline and noncalcareous to strongly calcareous.
COMPETING SERIES: These are the Ager, Aikman, Ant Flat, Cardon, Goring, Hiibner, Nebeker and Springerville series. Ager, Aikman, Cardon, Hiibner, Nebeker and Springerville soils have mean annual temperature warmer than 47 degrees F. Also, Cardon soils have chroma of less than l.5 throughout the upper 12 inches, Hiibner soils have very strong clay argillic horizons, and Nebeker soils have argillic horizons. Ant Flat and Goring soils have argillic horizons.
GEOGRAPHIC SETTING: Obray soils occur on gently sloping to moderately steep north and east mountain slopes at elevations of 5,500 to 7,000 feet. Slope gradients are 1 to 20 Percent. In uncultivated areas, gilgai micro-relief is evident. The climate is moist subhumid with warm, dry summers and cold, moist winters. The average annual precipitation is 18 to 25 inches, the mean annual temperature is 42 degrees to 45 degrees F., the mean summer temperature is 62 degrees to 65 degrees F., and the frost-free period is 60 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Yeates Hollow soils and the competing Goring, and Hiibner soils. Yeates Hollow soils have very cobbly clay argillic horizons.
DRAINAGE AND PERMEABILITY: Well-drained; slow to moderately rapid runoff; very slow permeability.
USE AND VEGETATION: Used for rangeland and dry cropland. The native vegetation is mulesear dock, Idaho fescue, low sagebrush, native bluegrass, slender wheatgrass and geranium.
DISTRIBUTION AND EXTENT: Northern Utah. The series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Cache Area, Utah 1969.
REMARKS: The Obray soils were formerly classified as Grumusols.
OSED scanned by NSSQA. Last revised by state 4/71.