LOCATION OREOKE WAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Pachic Ultic Argixerolls
TYPICAL PEDON: Oreoke stony silt loam - forested on a 65 percent southeast-facing slope at an elevation of 1,200 feet. (Colors are for dry soils unless otherwise noted.)
A1--0 to 5 inches; brown (7.5YR 4/2) stony silt loam, dark brown (7.5YR 3/2) moist; weak fine granular structure; soft, very friable, nonsticky and slightly plastic; many very fine and fine roots; many fine irregular pores; 15 percent gravel and 5 percent surface stones; slightly acid (pH 6.4); clear smooth boundry. (4 to 8 inches thick)
A2--5 to 15 inches; brown (7.5YR 5/2) gravelly silt loam, dark brown (7.5YR 3/2) moist; weak fine subangular blocky structure; soft, friable, slightly sticky and slightly plastic; many very fine and fine roots; common fine irregular and common fine tubular pores; 15 percent gravel and 5 percent cobbles; slightly acid (pH 6.4); clear wavy boundary. (8 to 12 inches thick)
AB--15 to 22 inches; brown (7.5YR 5/3) very gravelly silt loam, dark brown (7.5YR 3/3) moist; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and few fine and medium roots; common fine and medium tubular pores; 40 percent gravel and 10 percent cobbles; slightly acid (pH 6.2); clear wavy boundary. (6 to 10 inches thick)
Bt1--22 to 42 inches; brown (7.5YR 5/4) very gravelly clay loam, dark brown (7.5YR 3/4) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; common very fine, fine and medium roots; common fine and medium tubular pores; common faint clay films on faces of peds and in pores; 45 percent gravel, 10 percent cobbles and 5 percent stones; slightly acid (pH 6.2); clear wavy boundary. (20 to 25 inches thick)
Bt2--42 to 60 inches; dark yellowish brown (10YR 4/4) extremely gravelly clay loam, dark yellowish brown (10YR 3/4) moist; moderate medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; common fine and medium roots; few fine tubular pores; common distinct clay films on faces of peds and in pores; 50 percent gravel, 20 percent cobbles and 5 percent stones; moderately acid (pH 6.0)
TYPE LOCATION: Klickitat County, Washington; about 2 miles southwest of Klickitat; 2,580 feet south and 200 feet east of the northwest corner of section 28, T. 4 N., R. 13 E.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 48 to 51 degrees F. These soils are usually moist, but are dry in the moisture control section for 75 to 90 consecutive days following summer solstice. Clay content in the particle-size control section averages from 18 to 35 percent. The mollic epipedon is 20 to 30 inches thick and includes the A and AB horizons. Rock fragments in the control section average from 50 to 75 percent on a weighted average.
The A horizon has hue of 7.5YR or 10YR, value of 4 or 5 dry, 2 or 3 moist and chroma of 2 or 3 dry and moist. Reaction is moderately acid or slightly acid.
The AB horizon has hue of 7.5YR or 10YR and value of 4 or 5 dry. Texture is loam or silt loam with 35 to 60 percent rock fragments. Reaction is moderately acid or slightly acid.
The Bt horizon has hue of 7.5YR or 10YR, value of 4 to 6 dry and chroma 3 to 6 dry and moist. Texture is loam or clay loam with 35 to 80 percent rock fragments. Reaction is moderately acid or neutral.
COMPETING SERIES: These are the Badgermont, Lawyer and Tamming series. Badgermont soils have a lithic contact at a depth of 20 to 40 inches and are dry for 90 to 105 consecutive days. Lawyer soils are dry for 45 to 70 days and are neutral in the A horizon. Tamming soils are dry for 60 to 75 consecutive days following summer solstice.
GEOGRAPHIC SETTING: Oreoke soils are on canyon side slopes at elevations of 800 to 2,800 feet. Slopes are 15 to 75 percent. They formed in colluvium from basalt. Summers are warm and dry and winters are cool and moist. The mean annual precipitation is 15 to 25 inches. The average January temperature is 28 degrees F. and the average July temperature is 68 degrees F. The mean annual temperature is 47 to 50 degrees F. The frost-free season is 120 to 150 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dillcourt, Gunn, Leidl and Legall soils. Dillcourt soils have base saturation of more than 75 percent. Gunn soils have an ochric epipedon. Legall and Leidl soils have a mollic epipedon less than 20 inches thick. In addition, Leidl soils have a lithic contact at a depth of 20 to 40 inches.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderately slow permeability.
USE AND VEGETATION: These soils are used mainly for livestock grazing. Native vegetation is scattered Oregon white oak, antelope bitterbrush, bluebunch wheatgrass, Idaho fescue, elk sedge, lupine, and eriogonum.
DISTRIBUTION AND EXTENT: Klickitat County, Washington; MLRA 6, 8. The series is of small extent.
MLRA OFFICE RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Klickitat County, 2003.
REMARKS: Diagnostic horizons recognized in this pedon are:
Mollic epipedon - the zone from 0 to 22 inches
Argillic horizon - the zone from 22 to 60 inches
Particle-size control section - the zone from 22 to 42 inches with 60 percent rock fragments.