LOCATION VALLAN WAEstablished Series
TAXONOMIC CLASS: Loamy, mixed, superactive, frigid Lithic Haploxerepts
TYPICAL PEDON: Vallan ashy loam - grassland. (Colors are for dry soil unless otherwise noted.)
A--0 to 2 inches; brown (10YR 5/3) very dark grayish brown (10YR 3/2) moist ashy loam; moderate fine granular structure; soft, very friable, slightly sticky, slightly plastic; many roots; neutral (pH 6.7); abrupt smooth boundary. (1 to 3 inches thick)
Bw1--2 to 10 inches; yellowish brown (10YR 5/4) loam, dark yellowish brown (10YR 3/4) moist; moderate fine and medium granular structure; soft, very friable, slightly sticky, slightly plastic; many roots; slightly acid (pH 6.4); clear smooth boundary. (3 to 10 inches thick)
Bt--10 to 16 inches; yellowish brown (10YR 5/4) loam, dark brown (7.5YR 3/4) moist; moderate medium subangular blocky structure; hard, friable, slightly sticky, slightly plastic; common roots; common fine and medium pores; faint to distinct thick clay film in pores and on peds; 15 percent angular and rounded gravel and stones; slightly acid (pH 6.4); abrupt wavy boundary. (2 to 10 inches thick)
R--16 inches; hard slightly weathered andesite bedrock.
TYPE LOCATION: Ferry County, Washington; 500 feet east and 400 feet south of the northwest corner in the SW1/4NE1/4 sec. 26, T. 37 N., R. 32 E.
RANGE IN CHARACTERISTICS: Depth to a lithic contact ranges from 6 to 20 inches. The mean annual soil temperature at the lithic contact ranges from 44 to 46 degrees F. These soils are usually moist but are dry between a depth of 8 inches and the lithic contact for 60 to 75 consecutive days following the summer solstice. The particle-size control section is 10 to 18 percent clay and 5 to 25 percent rock fragments by weighted average. Reaction is slightly acid or neutral throughout.
The A horizon has hue of 7.5YR or 10YR, value of 4 or 5 dry, 2 or 3 moist; and chroma of 2 or 3 moist and dry.
The Bt 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 or moist. It is gravelly loam or loam and is 5 to 25 percent gravel, cobbles, and stones.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Vallan soils are on summits, shoulders, and backslopes of glacially scoured foothills and mountains. These soils formed mainly in colluvium and residuum from rhyodacite and andesite, with a minor component of glacial till. The upper part of the soil also contains an admixture of volcanic ash and loess. Slopes are 5 to 65 percent. Elevations range from 3,000 to 5,500 feet. The climate is characterized by warm, dry summers and cold, moist winters. The average annual precipitation is 15 to 25 inches. The mean January temperature is about 23 degrees F, the mean July temperature is about 64 degrees F, and the mean annual air temperature is about 43 degrees F. The frost-free period is 70 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Hum, Koepke, Molson, and Nevine soils. Hum soils are very deep and are on upland hill slopes. Koepke, Molson, and Nevine soils are deep. Keopke soils are on footslopes and backslopes of glaciated hills and mountains. Molson soils are on upland slopes. Nevine soils are on moraines, foothills and mountains.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability; slow to rapid runoff.
USE AND VEGETATION: Principal uses are livestock grazing and wildlife habitat. Native vegetation includes bluebunch wheatgrass, Idaho fescue, arrowleaf balsamroot, lupine, common yarrow, Wyeth eriogonum, common snowberry, and saskatoon serviceberry. Tree species are widely scattered, stunted Douglas-fir and ponderosa pine.
DISTRIBUTION AND EXTENT: Northcentral Washington. MLRA 6, 43A. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Ferry County (North Ferry Area), Washington, 1971.
REMARKS: Diagnostic horizons and features recognized in this pedon are an ochric epipedon from the surface to 7 inches, a cambic horizon from 2 to 16 inches, 15 percent rock fragments in the particle-size control section (from 10 to 16 inches), and a lithic contact at 16 inches.