LOCATION WILMA WAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, isotic, frigid Andic Haploxerepts
TYPICAL PEDON: Wilma stony fine sandy loam, under a coniferous forest on a 55 percent, convex, west-facing slope at an elevation of 4,000 feet. (Colors are for dry soil unless otherwise stated. All textures are apparent field textures)
A--0 to 4 inches; grayish brown (10YR 5/2) stony ashy fine sandy loam, very dark grayish brown (10YR 3/2) moist; weak moderate granular structure; soft, very friable, nonsticky and nonplastic; many fine and medium roots; common medium tubular pores; 15 percent gravel, 5 percent paragravel, 5 percent cobbles, 2 percent surface stones; NaF pH 9.6; neutral (pH 7.0);abrupt wavy boundary. (3 to 6 inches thick)
Bw--4 to 12 inches; brown (7.5YR 5/4) gravelly ashy sandy loam, brown (7.5YR 4/4) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; many fine and medium roots; many fine and medium tubular pores; 20 percent gravel, 5 percent paragravel, 5 percent cobbles; NaF pH 9.6; neutral (pH 6.8); abrupt wavy boundary. (6 to 11 inches thick)
2BC--12 to 24 inches; light yellowish brown (10YR 6/4) very gravelly fine sandy loam, dark yellowish brown (10YR 4/4) moist; weak medium subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; many fine roots; common fine and medium tubular pores; 50 percent gravel, 15 percent paragravel, 5 percent cobbles; NaF pH 9.2; neutral (pH 6.8); abrupt wavy boundary. (0 to 14 inches thick)
2C--24 to 37 inches; brownish yellow (10YR 6/6) very gravelly loamy sand, dark yellowish brown (10YR 4/6) moist; massive; slightly hard, friable, nonsticky and nonplastic; common fine roots; few fine tubular pores; 35 percent hard gravel, 50 percent paragravel; NaF pH 9.2; neutral (pH 6.8); abrupt wavy boundary. (10 to 15 inches thick)
2R--37 inches; granite.
TYPE LOCATION: Chelan County, Washington; about 4 miles southwest of 25 Mile Creek State Park; along USFS Road #2916; 2,000 feet west, 1,000 feet south of the northeast corner, sec. 33, T. 29 N., R. 20 E.
RANGE IN CHARACTERISTICS: Depth to diagnostic horizons and features are measured from the top of the first mineral layer. The average annual soil temperature ranges from 44 to 46 degrees F. These soils are usually moist, but are dry in all parts of the moisture control section for 60 to 90 consecutive days following the summer solstice. Depth to lithic contact ranges from 20 to 40 inches. The upper 10 to 14 inches of this soil has an estimated moist bulk density of 0.70 to 0.90 g/cc, volcanic glass content of 30 to 60 percent, acid-oxalate extractable aluminum plus one-half of the acid-oxalate extractable iron of 1.0 to 2.0 percent and 15-bar water retention of 5 to 12 percent for air dried samples. Rock fragments in the particle-size control section average 35 to 65 percent. Pararock fragment content ranges from 15 to 50 percent in the lower part of the control section and 0 to 5 percent in the upper part. Reaction is slightly acid or neutral throughout. Some pedons have an O horizon of undecomposed organic matter.
The A horizon has value of 4 to 6 dry, 3 or 4 moist, and chroma of 2 or 3 moist or dry. Surface stones and boulders range from 1 to 3 percent.
The Bw horizon has hue of 7.5YR or 10YR, value of 5 or 6 dry, 3 to 5 moist, and chroma of 2 to 4 moist or dry. Textures are gravelly ashy sandy loam, gravelly ashy fine sandy loam, or very gravelly ashy sandy loam. Angular granitic rock fragments range from 15 to 40 percent.
The 2BC horizon has hue of 10YR or 2.5Y, value of 5 or 6 dry, 4 or 5 moist, and chroma of 2 through 6 moist or dry. Texture is very gravelly or very cobbly fine sandy loam or very gravelly sandy loam. Angular granitic rock fragments range from 40 to 60 percent. Paragravel content range from 5 to 20 percent. Some pedons lack a BC horizon.
The 2C horizon has hue of 10YR or 2.5Y, value of 5 to 7 dry, 4 or 5 moist, and chroma of 2 through 6 moist or dry. Texture is very gravelly or extremely gravelly loamy sand, very gravelly coarse sandy loam, very cobbly coarse sandy loam, or very gravelly sandy loam. Angular granitic rock fragments range from 35 to 60 percent by volume. Paragravel content ranges from 15 to 50 percent.
COMPETING SERIES: These are the Kloochman, McCree, Newhorn, Redriver, and Veridge soils. Kloochman soils are dominated by gneiss or schist channers and flags in the lower part of the particle-size control section. McCree soils are more than 40 inches deep. Newhorn soils have compact till at 20 to 40 inches. Redriver soils are dry for 90 consecutive days and have 50 to 75 percent basalt rock fragments. Veridge soils are over sandstone and lack the coarse sand in the substratum. Soils that have not been updated in the new classificaiton include the Belzar, Hartill, Inkler, Newbell, Ohscow, Oxerine, Talls, Threemile, and Wilmont series. Belzar soils are slightly alkaline or moderately alkaline and are effervescent in the 2C horizon within the particle-size control section. Hartill soils are moderately deep to a paralithic contact. Inkler, Newbell, Ohscow, Talls, Threemile, and Wilmont soils are more than 40 inches deep. Oxerine soils are dominated by flags and channers in the particle-size control section. Soils with the similar isotic mineralogy include the Inkler, Juandefuca, and Tunnelcreek series. Inkler and Juandefuca soils are greater than 60 inches deep to bedrock. Tunnelcreek soils are dry for 45 to 60 consecutive days and have 15-bar moisture content of more than 12 percent in the ash mantle (medial).
GEOGRAPHIC SETTING: Wilma soils are on backslopes, shoulders, ridgecrests, and spur ridges that usually have a southerly aspect of mountains. Slopes are 15 to 65 percent. Wilma soils formed in volcanic ash overlying residuum and colluvium from granitic rock with a thin mantle of ash. Elevations range from 2,400 to 5,800 feet. The climate is characterized by warm, dry summers and cool, moist winters. The average annual precipitation is about 18 to 35 inches. The mean January temperature is about 25 degrees F, the mean July temperature is about 65 degrees F, and the mean annual temperature is about 40 to 46 degrees F. The growing season at 28 degrees F is 90 to 175 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ramparter, Palmich, Angle, and the competing McCree soils. Ramparter, Palmich, and Angle soils are all deep.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff, moderate and moderately rapid permeability.
USE AND VEGETATION: Timber production, wildlife habitat, watershed, and recreation. Natural vegetation is ponderosa pine and Douglas-fir with an understory of pachystima, shinyleaf spirea, kinnickinnick, strawberry ceanothus, antelope bitterbrush, willow, pinegrass, and elk sedge.
DISTRIBUTION AND EXTENT: North Central and Northeastern Washington; MLRA 6. Series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Chelan County, Washington, 1995. Cashmere Mountain Soil Survey.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from 0 to 4 inches (A horizon)
Cambic horizon - the zone from 4 to 12 inches (Bw horizon)
Andic feature - the zone from 0 to 12 inches (A and Bw horizons)
Lithic contact - the zone beginning at 37 inches (2R horizon)
Particle-size control section - the zone from 10 to 37 inches (part of the Bw, 2BC, and 2C horizons)
The discontinuity in the 2BC horizon represents the limit of the andic feature and the influence of air-fall volcanic ash.