LOCATION SANPOIL WAEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, frigid Cumulic Endoaquolls
TYPICAL PEDON: Sanpoil silt loam - on a 1 percent slope, at 1,920 feet elevation under pasture. (Colors are for dry soil unless otherwise stated.)
Ap--0 to 12 inches; dark grayish brown (10YR 4/2) silt loam, very dark gray (10YR 3/1) moist; common fine distinct dark yellowish brown (10YR 4/4) moist mottles; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine roots; common very fine and fine irregular pores; neutral (pH 6.8); clear wavy boundary.
A--12 to 28 inches; dark grayish brown (10YR 4/2) loam, very dark gray (10YR 3/1) moist; common fine faint dark yellowish brown (10YR 4/4) moist mottles; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine roots, common very fine and fine irregular pores; 5 percent fine pebbles; neutral (pH 6.8); abrupt wavy boundary. (Combined thickness of the A horizon is 24 to 37 inches.)
AC--28 to 31 inches; brown (10YR 5/3) sandy loam, dark brown (10YR 3/3) moist; many fine distinct dark yellowish brown (10YR 4/4) moist mottles; massive; soft, very friable, nonsticky and nonplastic; common very fine roots; common very fine and fine irregular pores; 5 percent fine pebbles; neutral (pH 6.6); abrupt wavy boundary. (3 to greater than 36 inches thick)
Ab--31 to 41 inches; grayish brown (10YR 5/2) fine sandy loam, very dark grayish brown (10YR 3/2) moist; common fine faint dark brown (10YR 3/3) moist mottles; weak medium subangular structure; slightly hard, friable, nonsticky and nonplastic; few very fine roots; common very fine and fine irregular pores; 5 percent fine pebbles; neutral (pH 6.6); abrupt wavy boundary. (0 to 10 inches thick)
2C--41 to 60 inches; multicolored very gravelly sand; single grain; loose, nonsticky and nonplastic; 40 percent pebbles, 10 percent cobbles; neutral (pH 7.2).
TYPE LOCATION: Colville Indian Reservation, Ferry County, Washington; about 14 miles south of the town of Republic; 2,100 feet north and 1,100 feet west of the southeast corner of sec. 14, T. 34 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 saturated in the moisture control section from winter through late spring. The particle-size control section is 5 to 18 percent clay and 0 to 15 percent rock fragments by weighted average. Reaction is slightly acid or neutral.
The A horizon has value of 4 or 5 dry, 2 or 3 moist, and chroma of 1 or 2 dry or moist. It is silt loam or loam in the lower part. It is 0 to 15 percent pebbles.
The AC horizon has hue of 10YR, 2.5Y, or 5Y; value of 4 through 6 dry, 2 through 4 moist, and chroma of 1 through 3 dry or moist. It is silt loam, loam, or sandy loam and may be gravelly. It is commonly stratified. Pebble content ranges from 0 to 20 percent.
The Ab horizon has value of 4 or 5 dry, 2 or 3 moist, and chroma of 1 or 2 dry or moist. It is silt loam, loam, or fine sandy loam and may be gravelly. Pebble content ranges from 0 to 20 percent. Some pedons lack an Ab horizon.
The 2C horizon has the same colors as the C horizon or is multicolored. Textures range from sandy loam to very gravelly sand and stratification is common. It is 0 to 50 percent pebbles and 0 to 10 percent cobbles. The 2C horizon is below 60 inches in some pedons.
COMPETING SERIES: These are the Conway, Four Star, and Schrader series. Conway soils usually dry between a depth of 10 and 33 inches from about August 15 to November 15 and average 15 to 30 percent have rock fragments mainly pebbles in the particle-size control section. Schrader soils lack a buried A horizon and are up to 15 percent exchangeable sodium in the particle-size control section.
GEOGRAPHIC SETTING: Sanpoil soils are on flood plains and low stream terraces. These soils formed in recent alluvium of mixed mineralogy. Slopes are 0 to 2 percent. Elevations range from 1,600 to 3,800 feet. The climate is characterized by warm, dry summers and cold, moist winters. The average annual precipitation is 15 to 20 inches. The mean January temperature is about 22 degrees F, mean July temperature is about 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 Loony, Louploup, Martella, Parmenter, Ret, Stapaloop, and Wapal soils. Loony and Martella soils are moderately well drained. Louploup, Parmenter, and Stapaloop soils are well drained. Ret soils are somewhat poorly drained. Wapal soils are somewhat excessively drained. In addition, Loony, Louploup, Martella, Parmenter, Stapaloop, and Wapal soils lack a mollic epipedon.
DRAINAGE AND PERMEABILITY: Poorly drained and very poorly drained; very slow runoff to ponded; moderate permeability to the discontinuity; moderately rapid to rapid permeability below the discontinuity.
USE AND VEGETATION: Hay and pasture, grazing, wildlife habitat, and watershed are the principal uses. The native vegetation is quaking aspen, thinleaf alder, paper birch, willow, Douglas-fir, and western larch, with an understory of common snowberry, starry false-Solomons-seal, wood rose, Rocky mountain maple, Lewis mockorange, redosier dogwood, thimbleberry, American skunkcabbage, cow parsnip, false bugbane, blue wildrye, Dutch rush, and Dewey sedge.
DISTRIBUTION AND EXTENT: Northcentral Washington. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Ferry County, Colville Indian Reservation, Washington, 1987.
REMARKS: Diagnostic horizons and features recognized in this soil are a mollic epipedon from the surface to 41 inches, and a weighted average of 5 percent rock fragments in the particle-size control section. This soil previously was named Kegel Variant.