LOCATION EIGHTLAR OREstablished Series
TAXONOMIC CLASS: Clayey-skeletal, magnesic, mesic Typic Dystroxerepts
TYPICAL PEDON: Eightlar extremely stony clay - woodland, on a south-facing concave slope of 40 percent under mixed conifers at 1,660 feet elevation. When described, the soil was moist below a depth of 20 inches. (Colors are for moist soil unless otherwise stated.)
A1--0 to 3 inches; dark reddish brown (5YR 3/3) extremely stony clay, dark reddish brown (5YR 3/2) dry; strong very fine and fine subangular blocky structure; hard, firm, very sticky and very plastic; common very fine roots; many very fine pores; 15 percent gravel, 20 percent cobbles and 30 percent stones; slightly acid; clear wavy boundary. (1 to 5 inches thick)
A2--3 to 10 inches; dark reddish brown (5YR 3/3) extremely stony clay, dark reddish brown (5YR 3/4) crushed, dark reddish brown (5YR 3/3) dry; strong fine and medium angular blocky structure; hard, firm, very sticky and very plastic; common very fine and few fine roots; many very fine pores; 15 percent gravel, 20 percent cobbles and 30 percent stones; slightly acid; clear wavy boundary. (3 to 8 inches thick)
Bw1--10 to 19 inches; dark reddish brown (5YR 3/3) extremely stone clay, dark reddish brown (5YR 3/4) crushed, dark reddish brown (5YR 3/3) dry; strong fine and medium angular blocky structure; hard, firm, very sticky and very plastic; common very fine and few fine roots; few fine tubular and many very fine pores; many stress cutans on faces of peds; 20 percent gravel, 25 percent cobbles and 25 percent stones; neutral; clear wavy boundary. (0 to 12 inches thick)
Bw2--19 to 29 inches; dark reddish brown (5YR 3/4) and dark brown (7.5YR 3/4) very stony clay, dark brown (7.5YR 3/4) dry; strong medium prismatic structure parting to weak coarse and medium subangular blocky; very hard, very firm, very sticky and very plastic; few very fine and fine roots; common very fine tubular pores; many stress cutans on faces of peds; 15 percent gravel, 10 percent cobbles, 35 percent stones; neutral; clear irregular boundary. (9 to 15 inches thick)
Bt--29 to 44 inches; dark brown (7.5YR 3/2; 10YR 3/3) extremely stony clay, brown (7.5YR 4/4) dry; dark brown (7.5YR 3/2) dry coatings; moderate fine and medium angular blocky structure; hard, firm, very sticky and very plastic; few very fine roots; common very fine tubular pores, many stress cutans on faces of peds and common prominant clay films on faces of peds, gravel and in root channels; 20 percent pebbles, 10 percent cobbles, 40 percent stones; neutral; gradual irregular boundary. (0 to 16 inches thick)
C--44 to 61 inches; dark brown (7.5YR 3/2; 10YR 3/3) extremely stony clay, brown (7.5YR 4/4) dry; dark brown (7.5YR 3/2) dry coatings; massive; hard, firm, very sticky and very plastic; few very fine roots; common very fine tubular pores; many prominant clay films on rock fragments; 20 percent gravel, 10 percent cobbles, 40 percent stones; neutral.
TYPE LOCATION: Josephine County, Oregon; about 4 miles southwest of Selma; 1,900 feet south and 1,800 feet east of the NW corner or section 28, T.38S., R.8W.
RANGE IN CHARACTERISTICS: Solum thickness typically is 30 to 46 inches and ranges from 25 to 53 inches. Depth to bedrock is greater than 60 inches. The mean annual soil temperature is 47 degrees to 56 degrees F. These soils are usually moist, but are dry between depths of 4 and 12 inches for 45 to 65 consecutive days in the four months that follow the summer solstice. The 10- to 40 inch control section averages 55 to 65 percent clay and 40 to 80 percent total rock fragments of which 20 to 50 percent are cobbles and stones.
The A horizon has hue of 2.5YR to 7.5YR, value of 3 or 4 moist and dry, chroma of 3 or 4 moist and 2 through 4 dry. It is extremely stony clay or very stony clay loam with 15 to 25 percent gravel, 10 to 25 percent cobbles, and 15 to 30 percent stones.
The Bw horizon has hue of 5YR or 7.5YR, value of 3 or 4 moist and dry, and chroma of 3 through 6 moist, 2 through 4 dry. It is extremely stony clay or very stony clay with 55 to 65 percent clay. It has 20 to 30 percent gravel, 5 to 20 percent cobbles, and 15 to 30 percent stones. Some pedons may have few to common clay films below 29 inches.
The C horizon has hue of 5YR or 7.5YR, value of 3 or 4 moist, 3 to 5 dry and chroma of 2 through 4 moist and 3 or 4 dry. It is extremely stony clay or very stony clay with 55 to 65 percent clay. It has 15 to 25 percent gravel, 10 to 25 percent cobbles, 15 to 30 percent stones, and 0 to 35 percent soft rock fragments.
COMPETING SERIES: This is the Brockman series in another family. Brockman soils have less than 35 percent coarse fragments in the control section.
GEOGRAPHIC SETTING: Eightlar soils are on alluvial fans, broad ridgetops, and side slopes of mountains. Elevations are 600 to 4,000 feet. Slopes are 3 to 90 percent. The soils formed in colluvium and residuum weathered from peridotite or serpentinite bedrock. Mean annual temperature is 45 degrees to 55 degrees F., and the mean annual precipitation is 30 to 70 inches. The frost-free period is 100 to 170 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Brockman soils and the Dubakella, Foehlin, Pearsoll, and Takilma soils. Dubakella soils are 20 to 40 inches deep to bedrock. Foehlin soils have a mollic epipedon and have less than 35 percent rock fragments. Pearsoll soils are 10 to 20 inches deep to a lithic contact. Takilma soils have a mollic epipedon and are loamy-skeletal.
DRAINAGE AND PERMEABILITY: Well drained; very slow permeability.
USE AND VEGETATION: Eightlar soils are used for timber production, water supply wildlife habitat and grazing. Natural vegetation dominantly is Jeffrey pine, ponderosa pine, incense-cedar, Douglas fir, whiteleaf manzanita and California fescue.
DISTRIBUTION AND EXTENT: Southwestern Oregon, MLRA 5. The series is moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Josephine County, Oregon, 1979.
REMARKS: Formerly classified as clayey-skeletal, magnesic, mesic Typic Xerochrepts, competing series not updated at the time of reclassification.
Diagnostic horizons and features recognized in this pedon :
Ochric epipedon
Cambic horizon - from 10 to 44 inches (Bw1, Bw2, and Bt horizons)
ADDITIONAL DATA: Characterization data for 1 pedon from Siskiyou National Forest and by Oregon State University Laboratory, unpublished, 1977.