LOCATION SIXES OREstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, active, mesic Humic Pachic Dystrudepts
TYPICAL PEDON: Sixes channery silt loam - grassland, on a 12 percent southwest-facing slope at 2,560 feet elevation. (When described on October 26, 1990 the soil was moist throughout. Colors are for moist soils unless otherwise noted.)
A1--0 to 11 inches; very dark grayish brown (10YR 3/2) channery silt loam, grayish brown (10YR 5/2) dry; weak very fine subangular blocky structure parting to weak fine granular; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and fine roots; common very fine tubular pores; 30 percent channers; very strongly acid (pH 4.6); clear smooth boundary.
A2--11 to 17 inches; very dark grayish brown (10YR 3/2) channery silt loam, grayish brown (10YR 5/2) dry; weak fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine, and common fine roots; common fine tubular pores; 25 percent channers; very strongly acid (pH 4.6); clear smooth boundary. (Combined thickness of the A horizon is 12 to 18 inches)
Bw1--17 to 26 inches; very dark grayish brown (10YR 3/2) channery silt loam, brown (10YR 5/3) dry; moderate fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common fine roots; common fine tubular pores; 25 percent channers; very strongly acid (pH 4.6); clear wavy boundary.
Bw2--26 to 32 inches; very dark grayish brown (10YR 3/2) channery silt loam, brown (10YR 5/3) dry; moderate fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common fine roots; common very fine and fine tubular pores; 30 percent channers; very strongly acid (pH 4.6); abrupt wavy boundary. (Combined thickness of the Bw horizon is 8 to 22 inches)
R--32 inches; fractured schist.
TYPE LOCATION: Curry County, Oregon; about 1,000 feet south and 1,000 feet east of the northwest corner of section 14, T. 35 S., R. 13 W., W. M. (Latitude 42 degrees, 33 minutes, 01 seconds N.; Longitude 124 degrees, 13 minutes, 06 seconds W.)
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 47 to 54 degrees F. The soils are usually moist but are dry for less than 45 consecutive days in all parts between depths of 4 and 12 inches in the four months following the summer solstice. The particle-size control section averages 18 to 25 percent clay and has 15 to 30 percent total rock fragments. Depth to bedrock and solum thickness is 20 to 40 inches. The umbric epipedon is 20 to 40 inches thick and may include all or part of the Bw horizon.
The A horizon has value of 2 or 3 moist, 3 to 5 dry and chroma of 1 or 2 moist and dry. It is channery silt loam with 15 to 25 percent clay. It has 15 to 30 percent channers.
The Bw horizon has value of 3 or 4 moist, 4 to 6 dry and chroma of 2 or 3 moist and dry. It is channery silt loam or channery loam with 18 to 25 percent clay. It has 15 to 30 percent channers and 0 to 3 percent flagstones.
COMPETING SERIES: These are the Agness and Quailprairie series. These soils are greater than 60 inches deep to bedrock.
GEOGRAPHIC SETTING: Sixes soils occur in open grassland areas on metastable ridgetops and south-facing side slopes of mountains. Slopes are 0 to 60 percent. The soils formed in colluvium and residuum derived from schist or phyllite rock types of the Colebrooke Schist Formation. Elevations are 1,000 to 3,000 feet. The climate is characterized by warm, wet winters and hot, moist summers. The mean annual precipitation is 90 to 130 inches. The mean annual temperature is 45 to 53 degrees F. The frost-free period is 160 to 210 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Deadline, Edson, Goldbeach, Irma, Nailkeg, and the competing Agness soils. All of these soils occur on broad ridgetops or side slopes of mountains. Edson soils have argillic horizons. Deadline soils are 40 to 60 inches deep to bedrock and are loamy-skeletal. Goldbeach soils are 10 to 20 inches deep to bedrock. Irma soils are greater than 60 inches deep to bedrock and have an ochric epipedon. Nailkeg soils are loamy-skeletal. Goldbeach soils occur in open grassland areas on ridgetops and south-facing side slopes of mountains.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Sixes soils are used for wildlife habitat and recreation. The vegetation is brome, bluegrass, hedgehog dogtail, California oatgrass, bentgrass, dock, lupine, western brackenfern, lomatium, a few widely scattered Oregon white oak and canyon live oak, woodrush, sedges, and rushes.
DISTRIBUTION AND EXTENT: Mountainous areas of southwestern Oregon; MLRA 1. The series is not extensive.
MLRA OFFICE RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Curry County, Oregon, 1995.
REMARKS: Diagnostic horizons and features recognized in this pedon include:
Umbric epipedon - from the surface to a depth of 32 inches (A1, A2, Bw1, Bw2 horizons).
Pachic subgroup - based on dark colors to a depth of 32 inches and assumed organic matter content of 2 percent.
Particle-size control section - from 10 to 32 inches (part of A2 horizon, Bw1, Bw2 horizons).
ADDITIONAL DATA: Partial laboratory reference sample #590OR-015-003, NSSL, Lincoln, NE.