LOCATION WINCHUCK OR

Established Series
Rev. MHF/CDJ/RWL
01/2013

WINCHUCK SERIES

The Winchuck series consists of very deep, well drained soils that formed in alluvium from mixed sources. Winchuck soils are on high stream terraces. Slopes are 0 to 30 percent. The mean annual precipitation is about 80 inches and the mean annual temperature is about 54 degrees F.

TAXONOMIC CLASS: Fine, isotic, isomesic Typic Haplohumults

TYPICAL PEDON: Winchuck silt loam, pasture. (Colors are for moist soil unless otherwise noted.)

Ap--0 to 8 inches; dark brown (7.5YR 3/2) silt loam, brown (10YR 5/3) dry; moderate very fine subangular blocky structure parting to moderate fine granular; soft, very friable, slightly sticky and slightly plastic; many fine roots; many very fine irregular pores; strongly acid (pH 5.2); clear wavy boundary. (7 to 10 inches thick)

BA--8 to 18 inches; dark brown (7.5YR 3/2) silty clay loam, brown (10YR 5/3) dry; strong fine subangular blocky structure; hard, friable, slightly sticky and plastic; common fine roots; many very fine continuous tubular pores; strongly acid (pH 5.2); clear wavy boundary. (0 to 12 inches thick)

Bt1--18 to 24 inches; dark reddish brown (5YR 3/3) silty clay, reddish brown (5YR 5/4) dry; moderate medium subangular blocky structure parting to strong very fine subangular blocky; hard, firm, sticky and plastic; few fine roots; many very fine continuous tubular and irregular pores; nearly continuous distinct clay films on ped faces and in pores; strongly acid (pH 5.2); gradual wavy boundary.

Bt2--24 to 34 inches; dark reddish brown (5YR 3/4) silty clay, reddish brown (5YR 4/3) dry; moderate coarse subangular blocky structure parting to strong very fine subangular blocky; very hard, very firm, sticky and plastic; few fine roots; many very fine tubular and irregular pores; nearly continuous distinct clay films on ped faces and in pores; strongly acid (pH 5.2); clear wavy boundary. (Combined thickness of the Bt horizons ranges from 15 to 25 inches)

BCt--34 to 46 inches; brown (7.5YR 4/4) heavy silty clay loam, brown (7.5YR 5/4) dry; moderate very fine subangular blocky structure; hard, firm, sticky and plastic; few fine roots; many very fine continuous tubular pores; common distinct clay films on ped faces and in pores; strongly acid (pH 5.2); gradual wavy boundary. (7 to 15 inches thick)

2C--46 to 60 inches; strong brown (7.5YR 5/6) gravelly sandy clay loam, reddish yellow (7.5YR 6/6) dry; massive; very hard, firm, slightly sticky and slightly plastic; no roots; many very fine irregular pores; 30 percent gravel; strongly acid (pH 5.4).

TYPE LOCATION: Curry County, Oregon; located about 1980 feet south and 3300 feet west of the NE corner of section 6, T. 41 S., R. 12 W., W. M. (Latitude 42 degrees, 02 minutes, 01 seconds N, Longitude 124 degrees, 09 minutes, 56 seconds W)

RANGE IN CHARACTERISTICS: The mean annual soil temperature is 54 to 59 degrees F. The difference between mean summer and mean winter soil temperature varies from 5 to 9 degrees F. The soils are usually moist and are dry for less than 45 consecutive days in all parts between depths of 4 and 12 inches in the four months following the summer solstice. The difference between mean summer and mean winter soil temperature varies from 5 to 9 degrees F. The particle-size control section averages 45 to 60 percent clay. Solum thickness ranges from 36 to 60 inches. Reaction ranges from very strongly to strongly acid. Depth to stratified gravelly alluvial material is 40 to over 60 inches. The umbric epipedon is 10 to 20 inches thick. The C.E.C. of the solum by ammonium acetate is 15 to 35 meq. per 100 grams of clay. The base saturation (by sum of cations) at 50 inches below the top of the argillic horizon is 10 to 30 percent. The upper cubic meter of the solum contains 12 to 20 kilograms of organic carbon.

The A horizon has hue of hue of 10YR to 5YR, value of 2 or 3 moist, 4 to 5 dry and chroma of 2 or 3 moist and 2 to 4 dry. Organic matter is 4 to 8 percent.

The BA horizon has hue of 7.5YR or 5YR, value of 3 or 4 moist, 3 to 5 dry and chroma of 3 or 4 moist and dry. It is 35 to 40 percent clay. Organic matter is 2 to 4 percent.

The Bt horizon has hue of 5YR or 7.5YR, value of 3 or 4 moist, 4 to 6 dry and chroma of 3 to 6 moist and dry. It is silty clay or clay and has 45 to 60 percent clay. Organic matter is 2 to 4 percent.

The BCt horizon is commonly lighter colored and has hue of 5YR to 10YR, value of 4 or 5 moist and chroma of 4 to 6 moist and dry. It is silty clay loam or clay loam and has 35 to 40 percent clay.

The 2C horizon has hue of 7.5YR to 2.5Y, value of 5 to 7 moist, 6 to 8 dry and chroma of 6 to 8 moist and dry. It is typically gravelly sandy clay loam or very gravelly sandy clay loam with 20 to 35 percent clay and 25 to 55 percent gravel. Faint redox concentrations occur in some pedons.

COMPETING SERIES: These are the Bullgulch, Hunterscove, Loeb, Macklyn, Quinliven, Vandamme, and Wadecreek series. Bullgulch soils have a mean annual soil temperature of less than 54 degrees F., a particle-size control section averaging 35 to 45 percent clay, an umbric epipedon greater than 20 inches thick, and a hue of 10YR throughout the Bt horizon. Hunterscove soils have a mean annual soil temperature of less than 54 degrees F., a particle-size control section averaging 35 to 45 percent clay, and are 20 to 40 inches deep to a paralithic contact. Loeb soils have a particle-size control section averaging 35 to 45 percent clay and are 40 to 60 inches deep to a paralithic contact. Macklyn soils are 20 to 40 inches deep to a paralithic contact. Quinliven soils have an ochric epipedon, redox depletions with chroma of 2 or less below 50 inches, and are moderately well drained. Wadecreek soils have a mean annual soil temperature of less than 54 degrees F. and redox depletions occuring in the lower Bt horizon.

GEOGRAPHIC SETTING: Winchuck soils are on high stream terraces. Slopes are 0 to 30 percent. The soils formed in alluvium from mixed sources. Elevation is 100 to 400 feet. The climate is humid, characterized by warm wet winters and warm moist summers with fog. A strong marine influence limits the diurnal and annual range of temperature. The mean annual precipitation is about 70 to 90 inches. The mean annual temperature is about 52 to 57 degrees F. The frost-free period is 270 to 330 days. Winchuck soils are on the Senecal geomorphic surface.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bagness, Bayside, Bigriver, Ettersburg, and Pistolriver soils. Bagness, Bayside, Bigriver, and Pistolriver soils occur on floodplains. Ettersburg soils occur on low stream terraces. Bagnell and Ettersburg soils are fine-loamy and are well drained. Bayside and Bigriver soils lack argillic horizons. Pistolriver soils have contrasting textures at depths of 20 to 30 inches and are somewhat poorly drained.

DRAINAGE AND PERMEABILITY: Well drained; slow permeability.

USE AND VEGETATION: These soils are used for timber production, pasture, homesites, watershed, and wildlife habitat. Native vegetation is Douglas fir, grand fir, California laurel, redwood, red alder, bigleaf maple, tanoak, cascara buckthorn, salmonberry, western swordfern, evergreen huckleberry, and salal.

DISTRIBUTION AND EXTENT: Along coastal streams of southwestern Oregon; MLRA 4B. The series is of small extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California

SERIES ESTABLISHED: Curry County, Oregon, 1966. The source of the name is the Winchuck River in coastal southwestern Curry County.

REMARKS: Diagnostic horizons and features in this pedon include:

Umbric epipedon - from the surface to a depth of 18 inches (Ap, BA horizons).

Argillic horizon - from depth of 18 to 46 inches (Bt1, Bt2, BCt horizons).

ADDITIONAL DATA: Reference sample from pedon S72OR, samples 2-375-2 381, from Coos County, Oregon, sampled by SSL, Riverside, CA 9/73.

National Cooperative Soil Survey
U.S.A.