LOCATION MCDOUG WAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Cumulic Ultic Haploxerolls
TYPICAL PEDON: McDoug silt loam - forested on a 2 percent southeast-facing slope at 1,480 feet elevation. (Colors are for moist soil unless otherwise noted. All textures are apparent field textures.)
Oi--1 inch to 0; leaves and twigs.
A--0 to 6 inches; very dark grayish brown (10YR 3/2) silt loam, dark brown (10YR 3/3) dry; weak fine and medium granular structure; soft, very friable, nonsticky and nonplastic; many very fine and fine roots; many fine irregular pores; moderately acid (pH 5.8); clear wavy boundary. (5 to 7 inches thick)
AB--6 to 12 inches; dark brown (10YR 3/3) silt loam, dark yellowish brown (10YR 4/4) dry; weak fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine roots; many fine irregular and few fine tubular pores; moderately acid (pH 6.0); clear wavy boundary. (4 to 7 inches thick)
BA--12 to 25 inches; dark brown (10YR 3/3) clay loam, yellowish brown (10YR 5/4) dry; moderate fine and medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; many very fine and fine roots; many fine and medium irregular and common fine and medium tubular pores; slightly acid (pH 6.2); abrupt wavy boundary. (12 to 16 inches thick)
Bw--25 to 38 inches; dark yellowish brown (10YR 4/4) loam, light yellowish brown (10YR 6/4) dry; weak fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and nonplastic; few fine, medium, and coarse roots; many fine irregular and common medium and coarse tubular pores; slightly acid (pH 6.2); clear wavy boundary. (12 to 15 inches thick)
C--38 to 60 inches; dark yellowish brown (10YR 4/4) clay loam, light yellowish brown (10YR 6/4) dry; common medium distinct dark grayish brown (10YR 4/2) mottles; massive; hard, friable, slightly sticky and slightly plastic; few fine roots; few fine and medium tubular pores; slightly acid (pH 6.3).
TYPE LOCATION: Skamania County, Washington; about 4 miles north of Willard, 500 feet south and 1,200 feet east of the northwest corner of sec. 15, T. 4 N., R. 9 E.
RANGE IN CHARACTERISTICS: These soils are usually moist, but are dry in the moisture control section for 45 to 60 consecutive days following summer solstice. Mean annual soil temperature is 47 to 50 degrees F. The mollic epipedon is 24 to 30 inches thick. Depth to mottles with a chroma of 2 or less is 30 to 40 inches. These soils are moderately acid or slightly acid throughout.
The A and AB horizons have hue of 7.5YR or 10YR, value of 2 or 3 moist, 3 to 5 dry, and chroma of 2 to 4 moist or dry.
The Bw and BC horizons have hue of 7.5YR or 10YR, value of 2 or 3 moist, 5 or 6 dry, and chroma of 3 or 4 moist. Texture is clay loam, sandy clay loam, or silt loam.
The C horizon has hue of 7.5YR or 10YR, value of 3 or 4 moist, 5 or 6 dry, and chroma of 3 or 4 moist. It is clay loam, sandy clay loam, or gravelly sandy loam. Some pedons have stratified layers of sand and gravel in the lower part of the C horizon.
COMPETING SERIES: These are the
Chapman,
Eld, and
Nook series. Chapman
and Eld soils lack mottles with a chroma of 2 or less in the particle-size control section. Nook soils are dry in the moisture control section for more than 60 consecutive days.
GEOGRAPHIC SETTING: McDoug soils are on flood plains and low terraces at elevations of 800 to 1,600 feet. These soils formed in alluvium derived dominantly from basic igneous rock. Slopes are 0 to 3 percent. The climate is characterized by warm, dry summers and cool, wet winters. Average annual precipitation is 45 to 60 inches. The mean January temperature is about 31 degrees F, mean July temperature is about 62 degrees F, and the mean annual temperature is 47 to 50 degrees F. The frost-free season is 130 to 150 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the McElroy, Pillery, St. Martins, and Underwood soils. McElroy soils are medial-skeletal. Pillery soils are coarse-loamy. St. Martin soils are in a fine family. Underwood soils have an argillic horizon.
DRAINAGE AND PERMEABILITY: Moderately well drained; slow runoff; moderate permeability. Rare flooding occurs from March to May. An apparent water table is as high as 2.5 to 3.5 feet at time from March to May.
USE AND VEGETATION: Used for timber production, hayland, pastureland, and wildlife habitat. The native vegetaiton is Douglas-fir, red alder, western redcedar, black cottonwood, and bigleaf maple. Understory species include vine maple, hawthorne, wild rose, blackberry, thimbleberry, and snowberry.
DISTRIBUTION AND EXTENT: Skamania County, Washington. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Skamania County, Washington, 1987.
REMARKS: Diagnostic horizons and features included in this pedon:
Pachic epipedon - from 0 to 25 inches (A, AB, and BA horizons)
Cambic horizon - from 25 to 38 inches (Bw horizon)
Particle-size control section - from 10 to 40 inches.
Classification changed 6/98 based on addition of CEC activity classes to Soil Taxonomy.