LOCATION WILMONT WAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Andic Haploxerepts
TYPICAL PEDON: Wilmont ashy silt loam - on a north facing 62 percent slopes at an elevation of 2,940 feet under a mixed conifer canopy. (Colors are for dry soil unless otherwise stated.)
Oi--0 to 2 inches; needles, twigs, and partially decomposed organic matter; abrupt smooth boundary.
A--2 to 7 inches; brown (10YR 5/3) ashy silt loam, dark brown (10YR 3/3) moist; weak fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many very fine and fine, few medium and coarse roots; 10 percent channers; NaF pH 10.1; neutral (pH 7.0); clear wavy boundary. (0 to 5 inches thick)
Bw1--7 to 14 inches; yellowish brown (10YR 5/4) ashy silt loam, dark yellowish brown (10YR 4/4) moist; weak fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many very fine, common fine, medium and few coarse roots; 10 percent channers; NaF pH 9.8; neutral (pH 7.2); abrupt wavy boundary. (7 to 14 inches thick)
2Bw2--14 to 19 inches; light yellowish brown(10YR 6/4) very channery sandy loam, dark yellowish brown (10YR 4/4) moist; weak fine subangular blocky structure; soft, very friable, slightly stocky and slightly plastic; common very fine and fine, few medium and coarse roots; 40 percent channers and 5 percent flagstones; neutral (pH 7.2); gradual wavy boundary. (5 to 16 inches thick)
2Bw3--19 to 29 inches; light yellowish brown (10YR 6/4) very channery sandy loam, dark yellowish brown (10YR 4/4) moist; weak fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common very fine, few fine roots; 40 percent channers, 5 percent pebbles, and 10 percent flagstones; neutral (pH 7.0); clear wavy boundary. (0 to 14 inches thick)
2C1--29 to 49 inches; brown (10YR 5/3) extremely channery loamy sand, dark brown (10YR 4/3) moist; single grain; loose, nonsticky and nonplastic; few very fine, fine, and medium roots; 55 percent channers, 5 percent pebbles, 10 percent flagstones, and 2 percent stones; neutral (pH 7.2); clear wavy boundry. (10 to 35 inches thick)
2C2--49 to 60 inches; dark grayish brown (10YR 4/2) extremely channery sand, very dark grayish brown (10YR 3/2) moist; single grain; loose, nonsticky and nonplastic; few very fine roots; 50 percent channers, 10 percent pebbles, 20 percent flagstones and 2 percent stones; neutral (pH 7.2)
TYPE LOCATION: Colville Indian Reservation; Ferry County, Washington; about 16 miles southwest of the town of Inchelium; 550 feet east and 1,975 feet north of the southwest corner sec. 14, T. 31 N., R. 34 E. W.M.
RANGE IN CHARACTERISTICS: The mean annual soil temperature at a depth of 20 inches ranges from 44 to 46 degrees F. These soils are usually moist but are dry in all parts between a depth of 8 to 24 inches for 60 to 75 consecutive days following the summer solstice. The volcanic ash mantle ranges from 7 to 14 inches thick and has an estimated moist bulk density of 0.75 to 0.85 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. Thickness of the solum ranges from 20 to 30 inches. The particle-size control section averages 35 to 60 percent rock fragments and 7 to 15 percent clay.
The A horizon has value of 4 or 5 dry, chroma of 2 or 3 dry or moist. This horizon is 0 to 10 percent channers, and 0 to 10 percent pebbles. Some pedons do not have an A horizon.
The Bw horizon has value of 5 or 6 dry, 3 or 4 moist and chroma of 3 or 4 dry or moist. It is ashy silt loam, ashy loam, or channery ashy silt loam. It contains 5 to 20 percent channers, 0 to 10 percent pebbles, and 0 to 5 percent cobbles.
The 2Bw horizon has hue of 10YR or 2.5Y, value of 5 through 7 dry, 3 through 5 moist, and chroma of 2 through 4 dry or moist. It is very channery loam or very channery sandy loam. It is 20 to 45 percent channers, 0 to 20 percent pebbles, 0 to 10 percent flagstones, 0 to 15 percent cobbles, and 0 to 15 percent soft coarse fragments.
The 2C1 horizon has hue of 7.5YR, 10YR, or 2.5Y, value of 5 or 6 dry, 3 or 4 moist, and chroma of 2 through 4 dry or moist. It is extremely channery loam, very channery sandy loam or extremely channery loamy sand. It is 30 to 55 percent channers, 0 to 20 percent pebbles, 0 to 10 percent flagstones, 0 to 10 percent cobbles, 0 to 5 percent stones, and 0 to 15 percent soft rock fragments.
The 2C2 horizon has hue of 7.5YR, 10YR or 2.5Y, value of 4 through 6 dry, 3 or 4 moist, and chroma of 2 through 4 dry or moist. It is very channery sandy loam, extremely channery loamy sand, or extremely channery sand. It is 30 to 60 percent channers, 0 to 20 percent pebbles, 0 to 20 percent flagstones, 0 to 10 percent cobbles, 0 to 5 percent stones, and 0 to 15 percent soft rock fragments.
COMPETING SERIES: These are the Belzar, Hartill, Kloochman, McCree, Newbell, Newhorn, Ohscow, Oxerine, Redriver, Talls, Threemile and Wilma series. Belzar, Hartill, Kloochman, Oxerine and Wilma soils have a lithic contact at 20 to 40 inches. Ohscow soils are dominated by angular granitic rock fragments. McCree soils have a volcanic ash mantle 14 to 27 inches thick. Newbell soils have sola 10 to 14 inches thick and contain mainly rounded and subrounded rock fragments. Tall soils have distinct clay bands in the 2A and 2B horizons and are 18 to 25 percent clay in the lower part of the control section. Threemile soils are slightly alkaline or moderately alkaline and have secondary carbonates in the lower part of the control section.
GEOGRAPHIC SETTING: Wilmont soils are on toeslopes, footslopes, and backslopes of mountains. Elevations range from 2,200 to 3,300 feet. These soil formed in colluvium and residuum from sedimentary and metasedimentary rock with a mantle of volcanic ash and loess. Slopes are 20 to 65 percent. The climate is characterized by warm, dry summers and cool, moist winters. The average annual precipitation is 18 to 25 inches. Mean January temperature is about 23 degrees F, mean July temperature is about 64 degrees F, and the mean annual air temperature is about 43 degrees F. The frost-free season is 90 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Henneway (T), Buhrig, Raisio, Rufus, Wellscreek (T), and the competing Hartill amd Oxerine soils. Henneway soils have less than 35 percent coarse fragments and 18 to 35 percent clay in the particle-size control section. Buhrig soils have a cryic temperature regime and bedrock at 20 to 40 inches. Raisio and Rufus soils have a mesic temperature regime and are on south facing slopes. Wellscreek soils have a mollic epipedon an d 18 to 30 percent clay in the particle-size control section.
DRAINAGE AND PERMEABILITY: Well drained; medium to very rapid runoff; moderate permeability in the solum, rapid in the substratum.
USE AND VEGETATION: Timber production, wildlife habitat, watershed, grazing and recreation are the principal uses. Native vegetation includes Douglas-fir, western larch, ponderosa pine, grand fir, and lodgepole pine, with an understory of pachystima, kinnikinnick, longtube twinflower, pinegrass. mallow ninebark, creambrush oceanspray, and Saskatoon serviceberry.
DISTRIBUTION AND EXTENT: Northeastern Washington. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Colville Indian Reservation; Ferry County, Washington, 1984.
REMARKS: Diagnostic horizons and features recognized in this soil are an ochric epipedon from 2 to 7 inches, a cambic horizon from 7 to 29 inches, and a particle-size control section from 10 to 40 inches from the mineral soil surface that averages 58 percent rock fragments.