LOCATION EDSON OREstablished Series
TAXONOMIC CLASS: Fine, mixed, active, mesic Typic Palehumults
TYPICAL PEDON: Edson channery clay loam - woodland, on a 25 percent south-facing slope at an elevation of 1,720 feet. (Colors are for moist soil unless otherwise noted. When described on September 6, 1990, the soil was dry to 13 inches and moist below this depth.)
Oi--2 inches to 0; partially decomposed needles, leaves, twigs, and woody materials.
A1--0 to 6 inches; reddish brown (5YR 4/4) channery clay loam, yellowish red (5YR 5/6) dry; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine, common medium, and few coarse roots; many very fine tubular pores; 15 percent channers; very strongly acid (pH 4.8); clear smooth boundary.
A2--6 to 13 inches; reddish brown (5YR 4/4) channery clay loam, yellowish red (5YR 5/6) dry; weak fine and medium subangular blocky structure; slightly hard, friable, sticky and slightly plastic; many very fine and fine, common medium, and few coarse roots; many very fine tubular pores; 15 percent channers; very strongly acid (pH 4.8); clear smooth boundary. (Combined thickness of the A horizon ranges from 10 to 15 inches)
Bt1--13 to 21 inches; reddish brown (5YR 4/4) channery silty clay, yellowish red (5YR 5/6) dry; moderate fine and medium subangular blocky structure; hard, firm, sticky and plastic; many very fine and fine, common medium, and few coarse roots; many very fine tubular pores; few faint clay films on ped faces and common distinct clay films in pores; 15 percent channers; very strongly acid (pH 5.0); abrupt wavy boundary.
Bt2--21 to 41 inches; yellowish red (5YR 4/6) channery silty clay, yellowish red (5YR 5/8) dry; moderate medium subangular blocky structure parting to strong fine subangular blocky; hard, firm, sticky and plastic; few fine, medium, and coarse roots; common fine tubular pores; common distinct clay films on ped faces and many prominent clay films in pores; 15 percent channers and 5 percent flagstones; very strongly acid (pH 5.0); gradual wavy boundary.
Bt3--41 to 72 inches: yellowish red (5YR 4/6) channery silty clay, yellowish red (5YR 5/8) dry; moderate medium subangular blocky structure parting to strong fine subangular blocky; hard, firm, sticky and plastic; few fine, medium, and coarse roots; common fine tubular pores; many prominent clay films on ped faces and in pores; 15 percent channers and 5 percent flagstones; very strongly acid (pH 5.0); gradual wavy boundary. (Combined thickness of the Bt horizon ranges from 50 to 60 inches)
Cr--72 inches; highly weathered schist.
TYPE LOCATION: Curry County, Oregon; located about 1,600 feet south and 1,100 feet west of the northeast corner of section 23, T. 35 S., R. 13 W. W.M.(Latitude 42 degrees, 32 minutes, 03 seconds N; Longitude 124 degrees, 19 minutes, 22 seconds W)
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 47 to 54 degrees F. The soils are usually moist and 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 35 to 50 percent clay and has 15 to 35 percent rock fragments. Depth to bedrock is greater than 60 inches. The solum is strongly to very strongly acid throughout.
The A horizon has hue of 5YR or 7.5YR, value of 4 or 5 moist, 5 or 6 dry and chroma of 4 through 6 moist and dry. It is channery clay loam with 27 to 35 percent clay. It has 15 to 25 percent channers and 0 to 5 percent flagstones.
The Bt horizon has hue of 5YR or 7.5YR, value of 4 or 5 moist, 4 through 6 dry and chroma of 4 through 6 moist and 6 through 8 dry. It is channery silty clay loam, channery silty clay, or channery clay with 35 to 50 percent clay. It has 15 to 25 percent channers and 0 to 10 percent flagstones.
The C horizon, when present, has hue of 10YR or 2.5Y, value of 5 or 6 moist, 6 or 7 dry and chroma of 4 through 8 moist and dry. It is channery silty clay, channery clay or flaggy silty clay with 40 to 50 percent clay. It has 10 to 20 percent channers and 5 to 15 percent flagstones.
COMPETING SERIES: These are the Cumley, Honeygrove, McCurdy, and Orford soils. All of these soils lack channer and flagstone rock fragments. Cumley soils have redox depletions with chroma of 2 or less in the lower part of the argillic horizon and are moderately well drained. McCurdy soils have high chroma masses of redox concentrations in the lower part of the argillic horizon and are moderately well drained. Honeygrove soils average more than 50 percent clay in the particle-size control section. Orford soils have an umbric epipedon.
GEOGRAPHIC SETTING: The Edson soils are on broad ridgetops and stable benches of mountains. Slopes are 0 to 30 percent. The soils formed in residuum and colluvium derived dominantly from schist and phyllite rock types of the Colebrooke Schist Formation. Elevations are 200 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. he frost-free period is 120 to 210 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Barkshanty, Deadline, Irma, and Nailkeg soils. All these soils are on broad ridgetops, stable benches and side slopes of mountains. In addition, Barkshanty soils are loamy-skeletal. Deadline, Irma, and Nailkeg soils lack argillic horizons.
DRAINAGE AND PERMEABILITY: Well drained; slow permeability.
USE AND VEGETATION: The soils are used mainly for timber production, pasture, homesites, watershed, and wildlife habitat. The native vegetation is Douglas fir, western hemlock, Port-Orford cedar, Pacific madrone, red alder, grand fir, tanoak, Pacific rhododendron, salal, evergreen huckleberry, western swordfern, cascade Oregongrape, red huckleberry, western brackenfern, common beargrass, and evergreen violet.
DISTRIBUTION AND EXTENT: Mountainous areas of southwestern Oregon; MLRA 1. The series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Curry County, Oregon, 1972. The source of the name is Edson Butte in northern Curry County.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon
Argillic horizon - from a depth of 13 to 72 inches (Bt1, Bt2, Bt3 horizons).
Pale feature - percentage of clay does not decrease from its maximum amount by more than 20 percent or more within a depth of 60 inches from the soil surface.
Particle-size control section - from 13 to 33 inches (Bt1 and part of Bt2 horizon).