LOCATION UNCAS              WA
Established Series
Rev. NCD/RJE/JAL
10/2002

UNCAS SERIES


The Uncas series consists of very deep, very poorly drained soils formed in alluvium, dominantly volcanic ash, with a surface layer of muck. Uncas soils are on bottomlands and in lake basins. Slopes are 0 to 3 percent. Average annual precipitation is about 30 inches, and the average annual temperature is about 44 degrees F.

TAXONOMIC CLASS: Ashy, glassy, nonacid, frigid Histic Vitraquands

TYPICAL PEDON: Uncas muck - cultivated. (Colors are for moist soils unless otherwise stated.)

Op--0 inches to 7; black (10YR 2/1) muck, dark gray (10YR 4/1) dry; about 15 percent fiber, less than 5 percent rubbed; moderate fine and medium granular structure; soft, friable, nonsticky and nonplastic; many very fine, fine, and few medium roots; neutral (pH 6.6) clear wavy boundary. (5 to 10 inches thick)

A--7 to 14 inches; very dark grayish brown (10YR 3/2) ashy silt loam, grayish brown (10YR 5/2) dry; few fine distinct dark brown (10YR 3/3) redox concentrations; moderate fine and medium subangular block structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine, fine, and few medium roots; neutral (pH 6.6); clear wavy boundary. (6 to 10 inches thick)

Bg--14 to 21 inches; light brownish gray (2.5Y 6/2) ashy silt loam, pale yellow (2.5Y 8/2) dry; few fine and medium distinct dark brown (10YR 3/3) redox concentrations; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, fine, and few medium roots; neutral (pH 6.8) clear wavy boundary. (6 to 9 inches thick)

Cg1--21 to 32 inches; light brownish gray (2.5Y 6/2) ashy silt loam, pale yellow (2.5Y 8/2) dry; common fine and medium distinct dark brown (10YR 3/3) redox concentrations; massive; slightly hard, friable, slightly sticky and slightly plastic; common very fine, fine, and few medium roots; neutral (pH 6.8); clear wavy boundary. (0 to 12 inches thick)

Cg2--32 to 37 inches; light olive brown (2.5Y 5/4) ashy silt loam, pale yellow (2.5Y 7/4) dry; common fine and medium distinct dark brown (10YR 3/3) redox concentrations; massive; slightly hard, friable, slightly sticky and slightly plastic; few very fine, fine, and medium roots; neutral (pH 6.8); clear wavy boundary. (0 to 6 inches thick)

Cg3--37 to 43 inches; dark olive gray (5Y 3/2) ashy silt loam, olive gray (5Y 5/2) dry; common fine and medium distinct light gray (5Y 7/1) redox depletions; massive; slightly hard, friable, slightly sticky and slightly plastic; few very fine, fine, and medium roots; neutral (pH 6.8); clear wavy boundary. (0 to 8 inches thick)

Cg4--43 to 67 inches; grayish brown (2.5Y 5/2) ashy silt loam, light gray (2.5Y 7/2) dry; many fine and medium distinct dark yellowish brown (10YR 4/4) redox concentrations; massive; slightly hard, friable, slightly sticky and slightly plastic; few very fine, fine, and medium roots; neutral (pH 6.8).

TYPE LOCATION: Pend Oreille County, Washington; 1,200 feet west and 300 feet south of the northeast corner sec. 26, T. 30 N., R. 45 E., W.M.

RANGE IN CHARACTERISTICS: Mean annual soil temperature is 45 to 47 degrees F. These soils are saturated during the winter and spring. The 0.02 to 2.0mm fraction is estimated to have 30 to 60 percent volcanic glass, acid-oxalate extractable aluminum plus one-half of the extractable iron of 0.4 to 1.0 percent and 15-bar water retention of less than 12 percent.

The Op horizon contains 20 to 30 percent organic carbon.

The A horizon has values of 2 to 4 moist, 4 to 6 dry, chroma of 1 or 2, moist and dry. Some pedons have an AB or AC horizon with value of 5 to 7 dry, 4 to 6 moist and chroma of l or 2 dry or moist.

The Bg and Cg horizons have hue of 2.5Y or 5Y; values of 3 through 6 moist, 5 through 8 dry, and dominately have chroma of 1 or 2, moist or dry. Redox concentrations range from few to many fine and medium. Reaction is neutral to slightly alkaline.

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: These soils are on bottomlands or lake basins. These soils formed in alluvium, dominantly volcanic ash, with a surface layer of muck. Slopes are 0 to 3 percent. Elevation ranges from 1,900 to 3,000 feet. Climate is continental characterized by warm, dry summers and cool, moist winters. Average annual temperature ranges from 42 to 45 degrees F. Average annual precipitation ranges from 18 to 35 inches. Frost-free season is about 90 to 120 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Hoodoo soils and Kegel and Pywell soils. Kegel soils are coarse-loamy. Pywell soil is a Histosol.

DRAINAGE AND PERMEABILITY: Very poorly drained; very slow runoff; moderate or moderately slow permeability. Some of these soils are partially artificially drained. The water table is at 1/2 to 1-1/2 feet during the winter and below 2 feet during the growing season.

USE AND VEGETATION: Most soil areas are cleared and used for hay or pasture. Principal vegetation on uncleared areas is quaking aspen, black cottonwood and western redcedar with an understory of common snowberry, wood rose, black hawthorn, redosier dogwood, western meadowrue, false Solomons-seal, spreading sweetroot, largeleaf avens, sweetscented bedstraw, and blue wildrye.

DISTRIBUTION AND EXTENT: Northeastern Washington. Series is of small extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana

SERIES ESTABLISHED: Pend Oreille County Area, Washington, 1981.

REMARKS: Diagnostic horizons and features recognized in this pedon are a histic epipedon from the surface to 7 inches and a cambic horizon from 14 to 21 inches.


National Cooperative Soil Survey
U.S.A.