LOCATION SKOKOMISH WAEstablished Series
TAXONOMIC CLASS: Coarse-silty, mixed, superactive, nonacid, mesic Fluvaquentic Endoaquepts
TYPICAL PEDON: Skokomish silt loam-cultivated (colors are for moist soil unless otherwise indicated).
Ap--0 to 8 inches; very dark grayish brown (10YR 3/2) silt loam; weak medium granular structure; friable; many roots; and slightly to moderately acid.
Bg1--8 to 15 inches; dark grayish brown (10YR 4/2) silt loam; few medium faint yellow and brown redox concentrations; weak fine and medium subangular blocky structure; slightly hard, friable; slightly to moderately acid and gradual smooth lower boundary.
Bg2--15 to 36 inches; dark grayish brown (10YR 4/2) silt loam, many fine distinct redox concentrations; weak fine and medium subangular blocky structure; slightly hard, friable; moderately acid; gradual smooth lower boundary.
Cg--36 to 60 inches; stratified grayish brown (10YR 5/2) silt loam and very fine sandy loam; many prominent redox concentrations becoming less prominent with depth; massive to weakly platy; slightly hard, friable; moderately acid; some thin strata of fine sand and clays.
TYPE LOCATION: Mason County, Washington. Skokomish River Valley, 500 feet south of the center of sec. 12 T. 21 N., R. 4 W.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 47 to 52 degrees F. The water table is as high as 1 foot to the soil surface at times from October to May, unless the soil is drained.
The Ap horizon has value of 2 or 3, 4 or 5 dry, and chroma of 1 to 3 moist and dry. It is moderately acid or slightly acid.
The Bg horizon has hue of 5Y, 2.5Y, or 10YR, value of 4 or 5, 5 to 7 dry, and chroma of 1 or 2 moist and dry and has few to many, faint to distinct redox concentrations. Reaction is moderately acid or slightly acid.
The Cg horizon has hue of 5Y, 2.5Y, or 10YR, value of 4 to 6, 5 to 7 dry, and chroma of 0 to 2 moist and dry and has many prominent redox concentrations. It is mostly stratified silt loam and very fine sandy loam above 48 inches and is stratified with layers of gravelly sand to clay below.
COMPETING SERIES: This is the Oridia series. Oridia soils have a dry value of 6 or 7 in the Ap horizon (not meet mollic subgroup).
GEOGRAPHIC SETTING: The Skokomish soils formed in recent alluvium on flood plains at an elevation of sea level to about 200 feet. Slopes are 0 to 3 percent. These soils are in a mild, marine climate. Summers are cool and relatively dry. Winters are mild and wet. Average annual precipitation is 60 to 90 inches. Mean January temperature is about 38 degrees F, mean July temperature is about 62 degrees F, and the mean annual temperature is about 50 degrees F. The frost-free season is 180 to 220 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Grove soils and the Dungeness Variant soils. Grove soils are on terraces and are well drained and sandy-skeletal. Dungeness Variant soils have a udic moisture regime and are moderately well drained.
DRAINAGE AND PERMEABILITY: Poorly drained; slow to ponded runoff; moderate permeability; these soils are subject co common, brief flooding from November to April; an apparent high water table is as high as the surface to 1 foot at times from November to April.
USE AND VEGETATION: Some is cleared and drained and used for cropland. Some is used for woodland and some for pasture. Native vegetation is red alder, western redcedar, western hemlock, and bigleaf maple, with an understory of vine maple, sedge, rush, salmonberry, devilsclub ladyfern, red elderberry, and western swordfern.
DISTRIBUTION AND EXTENT: Flood plain of the Skokomish River in western Washington. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Mason County, Washington, 1953.
REMARKS: Diagnostic horizons and features recognized in this pedon are an ochric epipedon from the surface to 8 inches, a cambic horizon from 8 to 36 inches and an assumed irregular decrease in organic carbon with depth based on stratified textures. The organic carbon is estimated to be more than 0.2 percent at 50 inches. The Ap horizon meets the color requirement for a mollic subgroup.