LOCATION WYNHOFF            WA
Established Series
Rev. WCH/RJE/TLA
07/2005

WYNHOFF SERIES


The Wynhoff series consists of moderately deep, well drained soils formed in colluvium and residuum from granite, rhyodacite porphyry and some metasedimentary rock with an admixture of loess. These soils are on shoulders, backslopes, and footslopes of hills and mountains. Slopes are 8 to 65 percent. The average annual precipitation is about 14 inches, and the mean annual temperature is about 48 degrees F.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Typic Haploxerolls

TYPICAL PEDON: Wynhoff stony loam-on a southeast facing 45 percent slopes, at an elevation of 2,260 feet under grasses and shrubs. (Colors are for dry soil unless otherwise stated).

A1--0 to 7 inches; brown (10YR 5/3) stony loam, dark brown (10YR 3/3) moist; moderate fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine and common fine roots; 20 percent gravel, 5 percent cobbles, 2 percent surface stones; neutral (pH 6.7); gradual wavy boundary.

A2--7 to 12 inches; yellowish brown (10YR 5/4) gravelly loam, dark brown (10YR 3/3) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine roots; 25 percent gravel and 5 percent cobbles; neutral (pH 6.8); clear wavy boundary. (Combined thickness of the A horizon is 9 to 18 inches).

Bw1--12 to 19 inches; light yellowish brown (10YR 6/4) very gravelly loam, brown (10YR 4/3) moist; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine roots, 35 percent gravel, 5 percent cobbles, and 2 percent stones, neutral (pH 6.8); clear wavy boundary.

Bw2--19 to 28 inches; light yellowish brown (10YR 6/4) very gravelly loam, brown (10YR 4/3) moist; weak medium subangular blocky structure slightly hard, friable, slightly sticky and slightly plastic; common very fine roots; 40 percent gravel, 10 percent cobbles, and 2 percent stones; neutral (pH 6.7); clear smooth boundary. (Combined thickness of the Bw horizon is 9 to 25 inches).

C--28 to 34 inches; light yellowish brown (10YR 6/4) extremely gravelly coarse sandy loam, yellowish brown (10YR 5/4) moist; massive; soft very friable, nonsticky and nonplastic; few very fine roots; 50 percent gravel, 10 percent cobbles, and 5 percent stones; neutral (pH 6.7); clear wavy boundary. (4 to 20 inches thick)

R--34 inches; slightly weathered rhyodacite porphyry.

TYPE LOCATION: Colville Indian Reservation; Ferry County, Washington, about 8 miles southeast of the town of Keller; 1,600 feet north and 350 feet west of the southeast corner of sec. 34, T. 29 N., R. 33 E. W.M.

RANGE IN CHARACTERISTICS: Depth to a lithic contact is 20 to 40 inches. The mean annual soil temperature is 49 to 51 degrees F. These soils are usually moist but are dry in all parts between a depth of 8 and 24 inches (or lithic contact) for 90 to 105 consecutive days following the summer solstice. The mollic epipedon is 10 to 18 inches thick. The particle-size control section averages 8 to 15 percent clay and 40 to 70 percent angular rock fragments. Reaction is neutral to slightly alkaline throughout.

The A horizon has value of 4 or 5 dry, 2 or 3 moist, and chroma of 2 through 4 dry, 2 or 3 moist. It is stony loam and may be gravelly or very gravelly loam or sandy loam in the lower part. It is 15 to 55 percent angular gravel, 0 to 10 percent cobbles, and 0.1 to 3 percent surface stones.

The Bw horizon has value of 5 through 7 dry, 3 through 5 moist, and chroma of 3 or 4 dry, 2 to 4 moist. It is loam, fine sandy loam, or sandy loam and is very gravelly or very cobbly. It is 20 to 60 percent angular gravel, 5 to 20 percent cobbles, and 0 to 5 percent stones.

The C horizon has hue of 10YR or 2.5Y, value of 5 to 7 dry, 4 through 6 moist, and chroma of 3 or 4 dry of moist. It is fine sandy loam, sandy loam, coarse sandy loam, or loamy coarse sand. It is very gravelly, very cobbly, extremely gravelly, or extremely cobbly. This horizon is 35 to 60 percent angular gravel, 5 to 20 percent cobbles, and 0 to 5 percent stones.

COMPETING SERIES: These are the Benco, Clint, Oldsferry and Storer series. Benco soils are very deep. Clint soils are from basalt and have hue of 7.5YR or 5YR. Oldsferry soils are from shale and have shaly and channery textural modifiers. Storer soils are deep to bedrock.

GEOGRAPHIC SETTING: Wynhoff soils are on shoulders, backslopes, and footslopes of hills and mountains. Elevations range from 1,400 to 4,700 feet. Slopes are 8 to 65 percent. These soils formed in colluvium and residuum from granite, rhyodacite porphyry and some metasedimentary rock with an admixture of loess. The climate is characterized by warm, dry summers and cold, moist winters. The average annual precipitation is 12 to 18 inches. The mean January temperature is about 25 degrees F, the mean July temperature is about 71 degrees F, and the mean annual air temperature is about 48 degrees F. The frost-free season is 110 to 150 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cashmont, Conconully, Couleedam, Ginnis, Johntom, Roosevelt, Scoap, Soaplake, Spokane, Swakane, and Tyee soils. Cashmont, Ginnis, Roosevelt, and Spokane soils are coarse-loamy. Couleedam, Johntom, Soaplake, and Swakane soils are shallow to a lithic contact. Tyee soils are shallow to a paralithic contact. Conconully soils are moderately deep to dense till. Scoap soils are frigid.

DRAINAGE AND PERMEABILITY: Well drained; slow to runoff; moderate permeability.

USE AND VEGETATION: Livestock grazing, wildlife habitat, and watersheds are the principal uses. The native vegetation is bluebunch wheatgrass, Idaho fescue, Sandberg bluegrass, silky lupine, arrowleaf balsamroot, common yarrow, Wyeth eriogonum, threetip sagebrush and scattered ponderosa pine.

DISTRIBUTION AND EXTENT: Northcentral Washington. The series is of small extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon

SERIES ESTABLISHED: Colville Indian Reservation; Ferry County, Washington, 1987.

REMARKS: Diagnostic horizons and features recognized in this soil are a mollic epipedon from the surface to 12 inches, a cambic horizon from 12 to 28 inches, a lithic contact at 34 inches, and an average of 50 percent rock fragments in the particle-size control section.

ADDITIONAL DATA: NSSL S95WA-047-005.


National Cooperative Soil Survey
U.S.A.