LOCATION ORIDIA WAEstablished Series
TAXONOMIC CLASS: Coarse-silty, mixed, superactive, nonacid, mesic Fluvaquentic Endoaquepts
TYPICAL PEDON: Oridia silt loam - pasture. (Colors are for moist soil unless otherwise noted.)
Ap--0 to 9 inches; dark grayish brown (10YR 4/2) silt loam, light brownish gray (2.5Y 6/2) dry; few fine prominent strong brown (7.5YR 5/6) redox concentrations, moderate medium granular structure; hard, friable, moderately sticky and moderately plastic; many fine and very fine roots; few fine tubular pores; moderately acid (pH 6.0); abrupt smooth boundary (8 to l2 inches thick)
Bg--9 to 17 inches; grayish brown (2.5Y 5/2) silt loam, light gray (2.5Y 7/2) dry; many medium prominent brown (7.5YR 4/4) redox concentrations, moderate medium and coarse subangular blocky structure; hard, friable, moderately sticky and moderately plastic; many roots; many fine tubular pores; slightly acid (pH 6.4); clear wavy boundary. (0 to l0 inches thick)
Cg1--17 to 42 inches; gray (2.5Y 5/1) silt loam, pale yellow (2.5Y 8/2) dry; many large prominent brown (7.5YR 4/4) and strong brown (7.5YR 5/6) redox concentrations, massive; hard, friable, moderately sticky and moderately plastic; common fine and very fine roots; few fine tubular pores; few thin lenses of very fine sand and fine sand; neutral (pH 6.8); abrupt smooth boundary. (5 to 36 inches thick)
Cg2--42 to 54 inches; dark gray (2.5Y 4/1) silty clay loam, light gray (5Y 7/2) dry; many large prominent strong brown (7.5YR 5/6) redox concentrations, massive; hard, friable, moderately sticky and moderately plastic; few very fine roots; few medium tubular pores; a discontinuous ortstein layer 1/4 inch thick of strong brown (7.5YR 5/6) and dark brown (7.5YR 3/4); neutral (pH 6.8); abrupt wavy boundary. (0 to 30 inches thick)
Cg3--54 to 60 inches; gray (5Y 5/l) silt loam, gray (5Y 6/l) dry; few medium prominent redox concentrations; massive; hard, friable, moderately sticky and moderately plastic; few very fine roots; interstitial pores; very strongly acid (pH 4.8).
TYPE LOCATION: King County, Washington; 850 feet north, 620 feet east of southwest corner sec. l3, T. 22 N., R. 4 E.
RANGE IN CHARACTERISTICS: Mean annual soil temperature is 50 to 54 degrees F. The particle-size control section averages 10 to 18 percent clay and less than 15 percent fine sand or coarser material. These soils have an irregular distribution of organic matter with depth.
The Ap horizon has hue of 10YR or 2.5Y, value of 3 or 4 moist, 6 or 7 dry.
The Bg and Cg horizons have hue of 2.5Y or 5Y, value of 4 or 5 moist, 6 to 7 dry, and chroma of 1 or 2 moist and dry. More than 60 percent of the soil has a chroma of 2 between 10 and 30 inches. It is moderately acid, slightly acid, or neutral silt loam or very fine sandy loam within 40 inches The Cg horizon ranges to very strongly acid silty clay loam in some parts below 40 inches in some pedons. Some pedons lack a B horizon.
COMPETING SERIES: This is the Skokomish series. Skokomish soils have a dry value of 5 or less in the Ap horizon (mollic subgroup).
GEOGRAPHIC SETTING: Oridia soils are on river floodplains at elevations of 20 to 500 feet. Slopes are 0 to 2 percent. The soils formed in recent alluvium. Oridia soils are in a marine climate with warm, dry summers, and cool, moist winters. Snow cover is intermittent. Average annual precipitation is 35 to 55 inches, which falls mostly between October and May. Each of the summer months has at least one inch of rainfall. Mean January temperature is 36 degrees F; mean July temperature is 62 degrees F. The mean annual temperature is 50 degrees F. The frost-free season is 150 to 190 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Briscot, Kline, Nooksack, Puget, Puyallup, and Sumas soils. Briscot soils are coarse- loamy. Kline soils are sandy-skeletal. Nooksack soils have a mollic epipedon and are moderately well drained. Puget soils are fine-silty. Puyallup soils have a mollic epipedon and are coarse-loamy over sandy or sandy-skeletal. Sumas soils are fine-silty over sandy or sandy- skeletal.
DRAINAGE AND PERMEABILITY: Poorly drained; very slow runoff; moderate permeability. These soils are subject to occasional brief flooding unless protected. An apparent water table is as high as 0 to 1 foot at times from November through April unless drained.
USE AND VEGETATION: Most is drained and used for cropland. Row crops and seeded grass and clover pasture are common crops. Native vegetation was western redcedar, red alder, and black cottonwood, with an
understory of western swordfern, salal, vine maple, devilsclub, western brackenfern, willow, Douglas spirea and rush.
DISTRIBUTION AND EXTENT: Northwestern Washington. The series is moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: King County area, Washington, l97l.
REMARKS: Diagnostic horizons recognized in this pedon are an ochric epipedon from 0 to 9 inches and a cambic horizon from 9 to 17 inches. The soils have an irregular decrease of organic carbon with depth and to have more than 0.2 percent organic carbon at a depth of 60 inches. The Ap horizon does not meet the color requirements for a mollic subgroup.