LOCATION WEDDERBURN OR
Established Series
Rev: MHF/RTS/RWL
01/2013
WEDDERBURN SERIES
The Wedderburn series consists of deep, well drained soils formed in colluvium and residuum from metasedimentary or metavolcanic rock. Wedderburn soils are on broad ridgetops and side slopes of coastal hills and mountains. Slopes are 0 to 90 percent. The mean annual precipitation is about 110 inches and the mean annual temperature is about 54 degrees F.
TAXONOMIC CLASS: Fine-loamy, isotic, isomesic Pachic Humudepts
TYPICAL PEDON: Wedderburn gravelly loam, woodland, on a 55 percent west-facing slope at an elevation of 480 feet. (Colors are for moist soil unless otherwise noted.)
Oi--0 to 1 inch; slightly decomposed litter of needles, leaves, mosses, twigs, and woody material.
A1--1 to 10 inches; very dark brown (10YR 2/2) gravelly loam, dark grayish brown (10YR 4/2) dry; moderate very fine subangular blocky structure; hard, friable, slightly sticky and slightly plastic; many fine and medium roots; many very fine continuous tubular pores; 15 percent gravel; strongly acid (pH 5.4); gradual smooth boundary.
A2--10 to 17 inches; very dark grayish brown (10YR 3/2) gravelly loam, grayish brown (10YR 5/2) dry; moderate very fine subangular blocky structure; hard, friable, slightly sticky and slightly plastic; many fine and medium roots; many fine continuous tubular pores; 15 percent gravel; strongly acid (pH 5.4); gradual wavy boundary.
A3--17 to 27 inches; very dark grayish brown (10YR 3/2) gravelly loam, brown (10YR 5/3) dry; moderate very fine subangular blocky structure; hard, friable, moderately sticky and slightly plastic; many fine and medium roots; many fine continuous tubular pores; 15 percent gravel; moderately acid (pH 5.6); gradual wavy boundary. (Combined thickness of the A horizon ranges from 20 to 30 inches)
Bw1--27 to 39 inches; dark brown (10YR 3/3) gravelly clay loam, pale brown (10YR 6/3) dry; moderate fine subangular blocky structure; hard, firm, moderately sticky and moderately plastic; many fine and medium roots; many fine continuous tubular pores; 20 percent gravel; moderately acid (pH 5.6); gradual wavy boundary.
Bw2--39 to 47 inches; olive brown (2.5Y 4/4) gravelly clay loam, pale yellow (2.5Y 7/4) dry; weak medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; common fine and medium roots; many fine continuous tubular pores; 25 percent gravel; strongly acid (pH 5.4); gradual wavy boundary. (Combined thickness of the Bw horizon ranges from 15 to 35 inches)
R--47 inches; siltstone.
TYPE LOCATION: Curry County, Oregon; located about 2250 feet south and 200 feet east of the northwest corner of section 10, T. 41 S., R. 13 W. (Latitude 42 degrees, 02 minutes, 30 seconds N; Longitude 124 degrees, 14 minutes, 21 seconds W)
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 54 to 59 degrees F. The difference between mean summer and mean winter soil temperature varies from 5 to 9 degrees F. The soils are usually moist and are dry less than 45 consecutive days between 4 and 12 inches in the four months following the summer solstice. The particle-size control section averages 20 to 30 percent clay and 20 to 30 percent rock fragments. Depth to bedrock and solum thickness is 40 to 60 inches. The umbric epipedon is 20 to 30 inches thick. The solum is moderately to strongly acid.
The A horizon has value of 2 or 3 moist, 4 or 5 dry and chroma of 2 or 3 moist and dry. It is gravelly loam with 15 to 27 percent clay. It has 15 to 25 percent gravel.
The Bw horizon has hue of 10YR or 2.5Y, value of 3 or 4 moist, 6 or 7 dry and chroma of 3 or 4 moist and dry. It is gravelly clay loam or gravelly silty clay loam with 27 to 35 percent clay. It has 20 to 35 percent gravel.
COMPETING SERIES: There are no competing soils. Soils with similar classification are the
Bosland,
Carlotta,
Coppercreek,
Devilscreek,
Ettersburg,
Hely,
Hookton, and
Watches series. Bosland soils are 20 to 40 inches to a lithic contact. Carlotta and Coppercreek soils have ochric epipedons. Carlotta soils are moderately well drained and very deep to bedrock. Devilscreek and Hookton soils have redox concentrations within the solum. Ettersburg soils have an umbric epipedon 10 to 20 inches thick. Hely soils cannot be used to compete due to the age of the official series description. Watches soils are greater than 60 inches deep to bedrock and have a mean annual soil temperature of less than 54 degrees F.
GEOGRAPHIC SETTING: Wedderburn soils are on broad ridgetops and side slopes of coastal hills and mountains. Slopes are 0 to 90 percent. The soils formed in colluvium and residuum derived dominantly from metasedimentary or metavolcanic rock types of the Dothan Formation. Elevations are 200 to 1300 feet. The climate is humid, characterized by warm wet winters and warm moist summers, with fog. A strong marine influence limits the diurnal and annual range of temperatures. The mean annual temperature is 52 to 57 degrees F. The mean annual precipitation is 90 to 130 inches. The frost-free period is 240 to 300 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing
Bosland soils and the
Dulandy,
Floras,
Guerin,
Loeb,
Macklyn,
Vondergreen, and
Zwagg soils. Bosland, Dulandy, Floras, Guerin, Loeb, Macklyn, and Vondergreen soils occur on adjacent redgetops and side slopes. Dulandy soils are 20 to 40 inches deep to a lithic contact and are loamy-skeletal. Floras soils are fine textured. Guerin soils are 10 to 20 inches deep to a lithic contact and are loamy-skeletal. Loeb, Macklyn, and Vondergreen soils have argillic horizons. Zwagg soils are on open grassland areas on adjacent ridgetops and side slopes, are 20 to 40 inches deep to a lithic contact, and are coarse-loamy.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: The soils are used for timber production, pasture, water supply, recreation, and wildlife habitat. Native vegetation is Douglasf-ir, coastal redwood, tanoak, California laurel, red alder, cascara buckthorn, evergreen huckleberry, salmonberry, and western swordfern.
DISTRIBUTION AND EXTENT: Coastal hills and mountains of southwestern Oregon; MLRA 4B. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Curry County, Oregon, 1995.
REMARKS: Diagnostic horizons and features recognized in this pedon include:
Umbric epipedon - from 1 to 27 inches. (A1, A2, A3 horizons)
Cambic horizon - from 27 to 47 inches. (Bw1, Bw2 horizons)
Particle-size control section - from 11 to 41 inches (A2, A3, Bw1, and upper Bw2 horizons)
All diagnostic horizons and features are measured from the top of the first mineral horizon.
ADDITIONAL DATA: Partial laboratory data from pedon 85T64, sample # 85T7407 from Curry County, Oregon samples by NSSL, Lincoln, NE, 8/85.
National Cooperative Soil Survey
U.S.A.