LOCATION CENTRALPEAK WAEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, frigid Andic Haploxerepts
TYPICAL PEDON: Centralpeak loam - on a southeast-facing 17 percent slope, at an elevation of 2,850 feet under a mixed conifer canopy. (Colors are for dry soil unless otherwise stated.)
Oi--0 to 2 inches; needles, twigs, cones, and partially decomposed organic matter; abrupt smooth boundary.
A--2 to 6 inches; dark grayish brown (10YR 4/2) ashy loam, very dark brown (10YR 2/2) moist; weak fine granular structure; soft, very friable, slightly sticky and nonplastic; common very fine, fine, medium, and coarse roots; 5 percent fine pebbles; NaF pH 10.5; neutral (pH 6.6); abrupt wavy boundary. (0 to 7 inches thick)
Bw1--6 to 14 inches; yellowish brown (10YR 5/4) ashy loam, dark yellowish brown (10YR 3/4) moist; weak medium subangular blocky structure; soft, very friable, slightly sticky and nonplastic; common very fine, fine, medium, and coarse roots; 5 percent fine pebbles; NaF pH 10.0; neutral (pH 6.6); abrupt wavy boundary. (6 to 14 inches thick)
2Bw2--14 to 22 inches; light yellowish brown (2.5Y 6/4) coarse sandy loam, dark yellowish brown (10YR 4/4) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine, fine, and few medium roots; 5 percent fine pebbles; slightly acid (pH 6.2); clear wavy boundary. (0 to 23 inches thick)
2C--22 to 31 inches; light olive brown (2.5Y 5/4) gravelly loamy coarse sand, olive brown (2.5Y 4/4) moist; massive; soft, very friable, nonsticky and nonplastic; few very fine roots; 15 percent pebbles; slightly acid (pH 6.4); abrupt smooth boundary. (0 to 15 inches thick)
2Cr--31 inches; weathered diorite bedrock that breaks to gravelly very coarse sand.
TYPE LOCATION: Colville Indian Reservation; Ferry County, Washington; about 6 miles northwest of the town of Keller; 1,500 feet south and 1,700 feet west of the northeast corner of sec. 35, T. 31 N., R. 32 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 is 7 to 14 inches thick and has an estimated moist bulk density of 0.65 to 0.95 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. . There may be a component (less than 60 percent) of volcanic ash in the solum to a depth of 20 inches. The particle-size control section averages 5 to 25 percent granitic rock fragments. Reaction ranges from moderately acid to neutral throughout.
The A horizon has value of 4 or 5 dry, 2 or 3 moist, and chroma of 2 or 3 dry or moist. It contains 0 to 10 percent pebbles. Some pedons do not have an A horizon.
The Bw horizon has hue of 7.5YR or 10YR, value of 5 or 6 dry, 3 or 4 moist, and chroma of 3 or 4 dry and 3 through 6 moist. It is silt loam, loam, or fine sandy loam, and is gravelly in some pedons. It is 0 to 25 percent pebbles, and 0 to 5 percent cobbles.
The 2Bw horizon has hue of 2.5Y or 10YR, value of 5 or 6, 3 or 4 moist, and chroma of 4 or 5 moist and dry. It is loam, coarse sandy loam, sandy loam, or gravelly sandy loam. It is 5 to 25 percent pebbles and 0 to 5 percent cobbles.
Some pedons have a 2BC horizon instead of, or in addition to, the 2Bw and 2C horizons. The 2C horizon is multicolored or has hue of 10YR or 2.5Y, value of 5 through 7 dry, 4 or 5 moist, and chroma of 2 through 4 dry or moist. It is sandy loam, coarse sandy loam, loamy sand, or loamy coarse sand, and is gravelly in some pedons. It is 5 to 30 percent pebbles, and 0 to 5 percent cobbles. Some pedons do not have a 2C horizon.
COMPETING SERIES: These are the Aits, Apex, Canteen, Leadpoint, Moscow, Moso, Ojibway, and Waits series. Aits, Apex, Canteen, Moso, and Waits soils are more than 40 inches deep. Leadpoint soils have chroma of 0 or 1 below the A horizon. Moscow and Ojibway soils are dry for 45 to 60 consecutive days following the summer solstice. In addition, Ojibway soils have hues of 7.5YR or 5YR throughout the particle-size control section.
GEOGRAPHIC SETTING: Centralpeak soils are on ridges, shoulders, backslopes, footslopes, and toeslopes of mountains. Elevations range from 2,200 to 4,500 feet. Slopes are 5 to 65 percent. These soils formed in colluvium and residuum from granitic rock with a mantle of volcanic ash and loess. The climate is characterized by warm, dry summers and cool, moist winters. The average annual precipitation is 16 to 25 inches. The mean January temperature is 23 degrees F, the mean July temperature is 64 degrees F, and the mean annual air temperature is 42 to 44 degrees F. The frost-free season is 90 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bearspring, Brusher, Capoose, Dinkelman, Nevine, Spokane, and the competing Canteen and Moscow soils. Bearspring, Brusher, Canteen, Dinkelman, and Nevine soils are deep. Capoose soils have a lithic contact between 20 and 40 inches. Spokane soils have a mollic epipedon and are mesic.
DRAINAGE AND PERMEABILITY: Well drained. Runoff is slow to very rapid. Permeability is moderate.
USE AND VEGETATION: Timber production, grazing, wildlife habitat, watershed, and recreation are the principal uses. Native vegetation includes Douglas-fir, ponderosa pine, western larch, lodgepole pine, Scouler willow, sitka alder, and Rocky Mountain maple. Understory vegetation includes pinegrass, mallow ninebark, creambush oceanspray, pachystima, kinnikinnick, dwarf and black mountain huckleberry, elk sedge, common princess pine, longtube twinflower, dwarf rose, Columbia brome, silky lupine, fat false-solomons-seal, white spirea, common snowberry, and snowbrush ceanothus.
DISTRIBUTION AND EXTENT: Northcentral Washington. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Colville Indian Reservation, Ferry County, Washington, 1987.
REMARKS: Diagnostic horizons and features recognized in this pedon are an ochric epipedon from 2 to 7 inches mixed, a cambic horizon from 6 to 22 inches that is dominated by volcanic ash to a depth of 14 inches, and a coarse-loamy particle-size control section from 12 to 31 inches.