LOCATION NOOKSACK           WA
Established Series
Rev. DES/RJE
10/2002

NOOKSACK SERIES


The Nooksack series consists of deep, moderately well drained soils formed in alluvium on floodplains and low river terraces. Slopes are 0 to 2 percent. Average annual precipitation is about 45 inches. Mean annual temperature is about 50 degrees F.

TAXONOMIC CLASS: Coarse-silty, mixed, superactive, mesic Fluventic Haploxerolls

TYPICAL PEDON: Nooksack silt loam, cultivated. (Colors are for moist soil unless otherwise stated.)

Ap1--0 to 2 inches; very dark grayish brown (10YR 3/2) silt loam, grayish brown (10YR 5/2) dry; few fine faint dark yellowish brown (10YR 4/4) mottles; weak thin platy structure; slightly hard, very friable; many roots; slightly acid (pH 6.1); abrupt smooth boundary.

Ap2--2 to 11 inches; very dark grayish brown (10YR 3/2) silt loam, grayish brown (10YR 5/2) dry; weak coarse prismatic structure; slightly hard, very friable; common roots; slightly acid (pH 6.1); abrupt smooth boundary. (combined thickness of the A horizon is 10 to 15 inches)

Bw--11 to 29 inches; dark grayish brown (2.5Y 4/2) heavy silt loam, light brownish gray (2.5Y 6/2) dry; weak medium prismatic structure that parts to weak medium subangular blocky structure; hard, friable, slightly sticky, slightly plastic; common roots; moderately acid (pH 6.0); clear smooth boundary. (5 to 21 inches thick)

C1--29 to 42 inches; dark grayish brown (10YR 4/2) and grayish brown (2.5Y 5/2) silt loam and thin lenses of very fine sandy loam, light brownish gray (2.5Y 6/2) dry; massive; slightly hard, very friable; common roots; slightly acid (pH 6.1); clear smooth boundary. (10 to 15 inches thick)

C2--42 to 60 inches; grayish brown (2.5Y 5/2) heavy silt loam, light brownish gray (2.5Y 6/2) dry; massive; hard, friable, sticky, plastic; common roots; moderately acid (pH 6.0).

TYPE LOCATION: About 1 1/2 miles northwest of Fall City, King County, Washington; 2,140 feet north and 1,800 feet east of the southwest corner sec. 4, T.24N., R.7E.

RANGE IN CHARACTERISTICS: The mean annual soil temperature is estimated to range from 47 to 52 degrees F. The particle-size control section averages 10 to 15 percent clay, less than 15 percent fine and coarser sand, and less than 1 percent coarse fragments. The soil is slightly acid or moderately acid.

The A horizon has value of 2 or 3 moist, 4 or 5 dry, and chroma of 2 or 3 moist and dry. It is weak coarse prismatic and weak thin platy structure.

The Bw horizon has value of 4 or 5 moist, 5 or 6 dry, and chroma of 2 to 4 moist and dry. It is mostly silt loam but some pedons have thin lenses of very fine sandy loam.

The C horizon has value of 4 or 5 moist, 5 or 6 dry, and chroma of 2 to 4 moist and dry and in some pedons is mottled below a depth of 36 inches. The C horizon contains (1/8 to 3/8 inch) lenses of very fine sandy loam in some pedons.

COMPETING SERIES: These are the similar Hampson, Malo, and Newberg series. Hampson soils are frigid. Malo and Newberg soils are coarse- loamy.

GEOGRAPHIC SETTING: Nooksack soils are on flood plains and low terraces from sea level to 500 feet. They formed in silty alluvium. These soils have a marine climate with cool, moist winters and warm, dry summers. The average annual precipitation is 35 to 55 inches. The average July temperature is 64 degrees F.; the average January temperature is 38 degrees F.; and the average temperature is 50 degrees F. The frost free season is about 190 days.

PRINCIPAL ASSOCIATED SOILS: These are the Oridia, Puget, Puyallup, and Sultan soils and the competing Newberg soils. Oridia and Puget soils have an ochric epipedon and aquic moisture regime. Puyallup soils are coarse-loamy over sandy or sandy-skeletal. Sultan soils are fine-silty and have an ochric epipedon.

DRAINAGE AND PERMEABILITY: Moderately well drained; moderate permeability; slow runoff.

USE AND VEGETATION: Used mostly for cropland. Row crop and seeded grass pasture are common crops. Native vegetation is Douglas-fir, western redcedar, and red alder, with an understory of trailing blackberry, salmonberry, western swordfern, Oregon-grape, and red elderberry.

DISTRIBUTION AND EXTENT: Northwestern Washington. Series is of small extent.

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

SERIES ESTABLISHED: King County, Washington 1943.

REMARKS: Diagnostic horizons and features recognized in this pedon are a mollic epipedon from the surface to 11 inches, a cambic horizon from 11 to 29 inches, and a particle-size control section from 10 to 40 inches, with an assumed irregular decrease in organic carbon. Organic carbon is assumed to be more than 0.3 percent at 60 inches.


National Cooperative Soil Survey
U.S.A.