LOCATION WILLANCH OREstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, nonacid, isomesic Fluvaquentic Humaquepts
TYPICAL PEDON: Willanch fine sandy loam, pasture. (Colors are for moist soil unless otherwise noted.)
Ap--0 to 8 inches; very dark grayish brown (10YR 3/2) fine sandy loam, grayish brown (10YR 5/2) dry; moderate fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and fine roots; many very fine irregular pores; common fine distinct yellowish brown (10YR 5/6) masses of iron accumulation; slightly acid (pH 6.2); clear smooth boundary. (6 to 10 inches thick)
AC--8 to 13 inches; dark brown (10YR 3/3) fine sandy loam, brown (10YR 5/3) dry; weak medium subangular blocky and moderate fine granular structure; slightly hard, very friable, slightly sticky and nonplastic; few fine and very fine roots; many fine irregular pores; common fine distinct yellowish brown (10YR 5/6) masses of iron accumulation; moderately acid (pH 5.8); clear smooth boundary. (4 to 9 inches thick)
C1--13 to 35 inches; dark grayish brown (2.5Y 4/2) sandy loam, light brownish gray (2.5Y 6/2) dry; massive; soft, very friable, slightly sticky and nonplastic; few fine roots; many fine tubular pores; many medium distinct yellowish brown (10YR 5/4) masses of iron accumulation; one inch layer of brown (10YR 5/3) fine sand within horizon; 10 percent fine gravel; moderately acid (pH 6.0); gradual smooth boundary. (15 to 20 inches thick)
C2--35 to 40 inches; dark grayish brown (10YR 4/2) loamy fine sand; massive; very friable, nonsticky and nonplastic; many very fine tubular pores; many medium distinct yellowish brown (10YR 5/4) masses of iron accumulation; one inch layer of dark grayish brown (2.5Y 4/2) silt loam; moderately acid (pH 6.0); gradual smooth boundary. (0 to 25 inches thick)
Cg--40 to 60 inches; dark grayish brown (2.5Y 4/2) and dark gray (N 4/ ) loamy sand; massive; very friable, nonsticky and nonplastic; many very fine tubular pores; many medium distinct yellowish brown (10YR 5/4) masses of iron accumulation; discontinuous strata of sand and silt loam; 10 percent fine gravel; few 1 to 10 mm. charcoal fragments; moderately acid (pH 6.0).
TYPE LOCATION: Coos County, Oregon; about 2 miles east of North Tenmile Lake on Big Creek bottom; 1,600 feet north and 600 feet east of the SE corner of section 1, T. 23 S., R. 12 W.
RANGE IN CHARACTERISTICS: The soil is saturated during the winter and has a temporary water table during stormy periods throughout the year unless drained. The mean annual soil temperature is about 53 degrees F. The difference between the mean summer and mean winter soil temperature varies from 5 to 9 degrees F. Soil depth is over 60 inches, but rooting depth may be limited by the seasonal water table. The umbric epipedon is 10 to 24 inches thick. The particle-size control section dominantly is sandy loam or fine sandy loam. Gravel content ranges from 0 to 10 percent. All horizons have redox concentrations that range from faint to prominent with moist value of 5 and chroma of 4 through 6 moist in the 10YR hue.
The A horizon has value of 2 or 3 moist, 4 or 5 dry, and chroma of 2 or 3 moist and dry.
The C horizon has hue of 2.5Y or 10YR, value of 4 or 5 moist, 5 through 7 dry, and chroma of neutral to 2 moist and dry. It is sandy loam, loamy fine sand, or loamy sand becoming coarser with increasing depth. In some pedons there are thin strata of finer textures below a depth of 35 inches. Moist chroma of 1 is below 30 inches.
COMPETING SERIES: These are the Brenner and Nestucca series in other families. Brenner soils are fine. Nestucca soils are fine-silty.
GEOGRAPHIC SETTING: Willanch soils are in shallow swales and concave depressions on flood plains at elevations from 0 to 100 feet. Slopes are 0 to 3 percent. The soils formed in mixed alluvial deposits consisting of coarse and moderately coarse textured material. Occasionally thin layers of fresh alluvium may be deposited on the surface by overflow water. The soils are in a cool wet marine climate with a mean annual precipitation of 50 to 90 inches. The mean January temperature is 43 degrees F., the mean July temperature is 61 degrees F., and the mean annual temperature is 50 to 53 degrees F. The frost-free period is 160 to 300 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Coquille, Langlois, Nehalem, and the competing Nestucca soils. All of these soils occur on floodplains. Coquille soils are in the fine-silty family. Langlois soils are in the fine family. Nehalem soils are in the fine-silty family and are well drained.
DRAINAGE AND PERMEABILITY: Poorly drained; moderately rapid permeability. These soils are subject to periods of flooding or ponding for brief durations from November through March. A seasonal water table is as high as 0.5 feet above the soil surface to 0.5 feet below the surface from November through March.
USE AND VEGETATION: The soils are used for pasture and forage crops. Native vegetation is clover and grasses, with shrubs, red alder, and tussocks.
DISTRIBUTION AND EXTENT: Coastal river valleys of western Oregon; MLRA 1. The series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Lane County Area, Oregon, 1981.
REMARKS: Diagnostic horizons and features recognized include:
Umbric epipedon - from 0 to 13 inches (Ap and AC horizons)
Aquic moisture regime - aquic conditions between 16 and 20 inches with chroma of 2 and redox concentrations directly below the umbric epipedon from 13 to 20 inches.
Nonacid feature - from 10 to 40 inches having pH of 5.0 or more.
Fluvaquentic features - irregular decrease in organic matter between 10 and 50 inches.
Aeric feature - chroma of 3 from 8 to 13 inches.