LOCATION AABAB                   WA

Established Series
Rev. SBC/RFP/JJR
02/2024

AABAB SERIES

The Aabab series consists of very deep, somewhat poorly drained soils that formed in mixed sedimentary alluvium derived from sandstone and siltstone. Aabab soils are on river terraces and proglacial lakes on till plains and slopes are 0 to 5 percent slope. The mean annual precipitation is about 90 inches and the mean annual temperature is about 49 degrees F.

TAXONOMIC CLASS: Fine-silty, isotic, isomesic Aquandic Dystrudepts

TYPICAL PEDON: Aabab medial silt loam, forested. (Colors are for moist soil unless otherwise noted.)

Oi--0 to 1 inch; slightly decomposed deciduous leaves and twigs; abrupt smooth boundary.

A1--1 to 4 inches; dark yellowish brown (10YR 3/4) medial silt loam, yellowish brown (10YR 5/4) dry; moderate medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common very fine and fine roots; many very fine tubular pores moderately acid (5.6); clear smooth boundary. (2 to 7 inches thick)

A2--4 to 12 inches; dark yellowish brown (10YR 4/4) medial silt loam, light yellowish brown (10YR 6/4) dry; moderate medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common fine, medium, and coarse roots; many very fine and common fine tubular pores; strongly acid (pH 5.4); clear wavy boundary. (6 to 11 inches thick)

Bw1--12 to 19 inches; dark yellowish brown (10YR 4/4) silty clay loam, light yellowish brown (10YR 6/4) dry; few fine and medium distinct grayish brown (10YR 5/2) redox depletions, light gray (10YR 7/2) dry, and common fine distinct yellowish red (5YR 4/6) redox concentrations, reddish yellow (5YR 6/8) dry; moderate coarse and very coarse prismatic structure; hard, firm, moderately sticky and slightly plastic; few fine roots; many very fine and fine tubular pores; strongly acid (pH 5.4); abrupt wavy boundary. (5 to 9 inches thick)

Bw2--19 to 22 inches; brown (10YR 5/3) silt loam, light gray (10YR 7/2) dry; common fine and medium distinct yellowish red (5YR 5/8) redox concentrations, reddish yellow (5YR 6/8) dry; moderate medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; few fine roots; few very fine tubular pores; moderately acid (pH 5.6); clear wavy boundary. (2 to 4 inches thick)

Bw3--22 to 44 inches; yellowish brown (10YR 5/4) silty clay loam, very pale brown (10YR 7/3) dry, many fine and medium distinct yellowish red (5YR 4/6) redox concentrations, yellowish red (5YR 5/8) dry; moderate very coarse prismatic structure parting to weak medium subangular blocky; hard, firm, moderately sticky and moderately plastic; few fine roots; many very fine and fine tubular pores; dark reddish brown (2.5YR 3/4) iron coatings on some peds, reddish brown (2.5YR 4/4) dry; strongly acid (pH 5.4); clear smooth boundary. (20 to 25 inches thick)

Cg--44 to 61 inches; greenish gray (5GY 5/1) silty clay loam, light gray (2.5Y 7/2) dry; few fine distinct dark greenish gray (5BG 4/1) redox concentrations, not visible when dry; massive; very hard, very firm, moderately sticky and moderately plastic; common very fine and fine tubular pores; moderately acid (pH 5.6).

TYPE LOCATION: Pacific County, Washington; 2/10 mile south of South Fork Nemah River bridge on U. S. Highway 101, then due west approximately 300 feet; SE1/4 section 11, T. 11 N., R. 10 W.

RANGE IN CHARACTERISTICS: The solum is 35 to 52 inches thick. The mean annual soil temperature is 47 to 55 degrees F. The particle-size control section has 25 to 35 percent clay. The soil is strongly acid to moderately acid. The ochric epipedon is 8 to 14 inches thick.

The A horizon has hue of 7.5YR or 10YR, value of 3 or 4 moist, 4 through 6 dry, and chroma of 3 through 5 moist or dry. When value is 3 and chroma is 3, the horizon is less than 10 inches thick. This horizon has granular or subangular blocky structure.

The Bw horizon has value of 4 or 5 moist, 5 through 7 dry, and chroma of 3 through 5 moist, 2 through 4 dry. It is silt loam or silty clay loam, and has prismatic or subangular blocky structure.

The Cg or Bg horizon has hue of 2.5Y, 5Y, or 5GY, value of 3 through 5 moist, 5 through 7 dry and chroma of 1 through 3 moist or dry. It is silt loam or silty clay loam.

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: Aabab soils are on river and stream terraces and proglacial lakes on till plains at elevations of 10 to 500 feet. Slopes are 0 to 5 percent. These soils formed from mixed sedimentary alluvium derived from sandstone and siltstone. They occur in a coastal marine climate with cool, wet winters and cool, dry summers. Mean annual precipitation ranges from 75 to 120 inches. The mean January temperature is 38 degrees F., mean July temperature is 60 degrees F., and the mean annual temperature is 49 degrees F. The growing season (28 degrees F.) is about 160 to 220 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Astoria, Humptulips, Lytell, Nuby, Satsop, Swem, Sylvia, Tealwhit, and Zenker soils. Astoria, Lytell, and Zenker soils are well drained. Satsop, Swem, and Sylvia soils are moderately well drained. Nuby and Tealwhit soils are poorly drained. Humptulips soils are somewhat excessively drained and have a coarse-loamy over sandy or sandy-skeletal control section.

DRAINAGE AND PERMEABILITY: Somewhat poorly drained; slow runoff; slow permeability.

USE AND VEGETATION: Timber production, agriculture, wildlife habitat, and recreation are the principal uses. Native vegetation is red alder, western redcedar, western hemlock, and Sitka spruce. Understory species are salal, swordfern, buttercups, and various mosses and grasses.

DISTRIBUTION AND EXTENT: West side of the Olympic Peninsula in western Washington; MLRA 4A. The series is of small extent.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: BOZEMAN, MONTANA

SERIES ESTABLISHED: Pacific County, Washington, 1978.

REMARKS: Diagnostic horizons and features recognized in this pedon include:
Andic properties - from 1 to 12 inches (A1 and A2 horizons)
Cambic horizon - from 12 to 44 inches
Aquic feature - from 12 to 19 inches having redox depletions and aquic conditions (Bw1 horizon)
Particle-size control section - from 10 to 40 inches
All depths to diagnostic horizons and features are measured from the top of the first mineral horizon.

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National Cooperative Soil Survey
U.S.A.