LOCATION WILLABY WAEstablished Series
TAXONOMIC CLASS: Fine, isotic, isomesic Andic Dystrudepts
TYPICAL PEDON: Willaby silt loam, on a 5 percent east facing slope under coniferous forest at 340 feet elevation. (Colors are for moist soil unless otherwise stated. All textures are apparent field textures. When described the soil was moist.)
01--1/2 to 2 1/2 inches; accumulation of leaves, needles, twigs and moss.
02--1/4 inch to 0; decomposed organic material.
A1--0 to 6 inches; dark reddish brown (5YR 3/3) silt loam, brown (7.5YR 4/4) dry; moderate fine granular structure; soft, very friable, slightly sticky and slightly plastic; common medium and coarse roots; many fine tubular and interstitial pores; about 2 percent subangular pebbles; very strongly acid (pH 4.6); clear smooth boundary. (4 to 7 inches thick)
A3--6 to 11 inches; dark brown (7.5YR 3/4) heavy silt loam, strong brown (7.5YR 5/6) dry; strong very fine and fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine and few medium and coarse roots; many very fine and fine interstitial pores; 2 percent subangular and rounded pebbles; very strongly acid (pH 4.8); abrupt smooth boundary. (4 to 6 inches thick)
B21--11 to 25 inches; strong brown (7.5YR 5/6) silty clay, reddish yellow (7.5YR 6/6) dry; moderate fine and medium subangular blocky structure; hard, friable, sticky and plastic; common very fine, and few fine, medium and coarse roots; many very fine tubular and interstitial pores; 5 percent subangular and rounded pebbles; very strongly acid (pH 4.8); clear smooth boundary. (12 to 16 inches thick)
IIB22--25 to 47 inches; yellowish brown (10YR 5/6) very gravelly silty clay, brownish yellow (10YR 6/6) dry; moderate fine subangular blocky structure; hard, friable, sticky and plastic; few very fine and fine roots; many very fine tubular and interstitial pores; 40 percent rounded and subangular pebbles and 5 percent cobbles; very strongly acid (pH 4.8); gradual smooth boundary. (18 to 24 inches thick)
IIC--47 to 63 inches; yellowish brown (10YR 5/4) extremely gravelly silty clay loam, very pale brown (10YR 7/4) dry; common fine distinct yellowish red (5YR 5/8) mottles; reddish yellow (5YR 6/8) dry; massive; hard, friable, sticky and plastic; common very fine interstitial pores; 60 percent subangular and rounded pebbles, 10 percent cobbles; very strongly acid (pH 4.6).
TYPE LOCATION: Grays Harbor County, Washington; about 3 miles north of Humptulips; 250 feet west, 2,540 feet north of the southeast corner of section 33, T.21N., R.10W., WM.
RANGE IN CHARACTERISTICS: Depth to the IIC horizon ranges from 40 to 60 inches. The particle size control section is 15 to 35 percent hard rock fragments and is 35 to 50 percent clay. The mean annual soil temperature is 49 to 52 degrees F.
The A horizon has hue of 5YR through 10YR moist, value of 3 or 4 moist and 4 or 5 dry and chroma of 3 or 4 moist and 4 through 6 dry. This horizon with a chroma of 3 is less than 10 inches thick.
The B horizon has hue of 7.5YR or 10YR and value of 5 or 6 moist. It is silty clay or heavy silty clay loam. Hard rock fragments range from 2 to 15 percent.
The IIB horizon has hue of 10YR or 7.5YR and value of 5 or 6 moist. It is gravelly or very gravelly silty clay or heavy silty clay loam. Hard subangular and rounded pebbles and cobbles range from 15 to 60 percent by volume.
The IIC horizon has value of 5 or 6 moist, 6 or 7 dry, and chroma of 4 or 6. It is silty clay or silty clay loam with 60 to 90 percent subangular and rounded pebbles and cobbles. This horizon is cemented or compacted below 40 inches in some pedons.
COMPETING SERIES: These are the Blachly, Dement, Desolation, Kilowan, and Melby series. All of these soils lack discontinuity in the control section. Also, Blachly soils are 5YR or 2.5YR in the B2 horizon. Dement soils have a hue of 5YR moist in the B horizon. Desolation soils have a solum more than 60 inches thick. Kilowan soils have a paralithic contact at 20 to 40 inches. Melby soils contain 5 to 15 percent weathered siltstone and shale fragments.
GEOGRAPHIC SETTING: Willaby soils are on piedmont outwash and till plains in the Olympic Mountains. Slopes are 0 to 15 percent. Elevations range from 100 to 500 feet. They are in a coastal marine climate with cool, wet winters and cool, dry summers. The annual precipitation is 110 to 150 inches. The mean January temperature is 38 degrees F.; the mean July temperature is 60 degrees F.; and the mean annual temperature is about 50 degrees F. The growing season (28 degrees F.) is 200 to 240 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Halbert, Nemah, Nordby and O'Brien soils. Halbert and Nemah soils have an aquic moisture regime. Nordby soils are loamy-skeletal and have an umbric epipedon. O'Brien soils are medial in the control section.
DRAINAGE AND PERMEABILITY: Moderately well drained; slow or medium runoff; moderately slow permeability.
USE AND VEGETATION: Principal uses are timber production, wildlife habitat, watershed and recreation. The major tree species are Douglas fir and western hemlock. Understory species include salal, western brachenfern and cascara.
DISTRIBUTION AND EXTENT: Central western Washington. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Grays Harbor County, Washington, 1979.
REMARKS: Classification only changed 4/94 because of recent amendments to Soil Taxonomy.