LOCATION ZENKER WAEstablished Series
TAXONOMIC CLASS: Medial, mixed, mesic Typic Fulvudands
TYPICAL PEDON: Zenker silt loam - forested. (Colors are for moist soil unless otherwise stated. All textures are apparent field textures.)
A--0 to 11 inches; very dark brown (10YR 2/2) silt loam, dark yellowish brown (10YR 3/4) dry; moderate medium and fine granular structure; soft, very friable, slightly sticky and slightly plastic, weakly smeary; many fine and very fine roots; many fine and very fine tubular pores; 60 percent weathered pebble-sized sandstone fragments; strongly acid (pH 5.4); gradual wavy boundary. (6 to 11 inches thick)
AB--11 to 17 inches; very dark grayish brown (10YR 3/2) silt loam, dark yellowish brown (10YR 4/4) dry; weak medium and fine subangular blocky structure; soft, friable, slightly sticky and slightly plastic, weakly smeary; common fine and very fine roots; many fine and very fine tubular pores; 10 percent weathered cobble-size sandstone fragments; 50 percent weathered pebble-sized sandstone fragments; moderately acid (pH 5.6); clear wavy boundary. (5 to 9 inches thick)
Bw--17 to 60 inches; brown (10YR 4/3) loam, yellowish brown (10YR 5/4) dry; weak medium and fine subangular blocky structure; soft, friable, slightly sticky and slightly plastic, weakly smeary; few fine and very fine roots; common very fine tubular pores; 10 percent weathered cobble-sized sandstone fragments, 55 percent weathered pebble-sized sandstone fragments; moderately acid (pH 5.8).
TYPE LOCATION: Wahkiakum County, Washington; 1,300 feet west and 300 feet south of the northeast corner of section 6, T. 9 N., R. 5 W.
RANGE IN CHARACTERISTICS: The solum thickness and depth to bedrock ranges from 40 to more than 60 inches. The 10- to 40- inch particle-size control section is 20 to 27 percent clay and averages 35 to 80 percent weathered sandstone fragments. Average annual soil temperature ranges from 47 to 51 degrees F. Organic carbon is less than 4 percent in some part of the 2/3's of the particle-size control section. The umbric epipedon ranges from 10 to 20 inches in thickness. Reaction ranges from moderately acid to extremely acid.
The A horizon has hue of 10YR or 7.5YR, value of 2 or 3 moist, 3 to 5 dry and chroma of 2 or 3 moist and 2 to 4 dry. It has 0 to 70 percent pebble-size weathered sandstone fragments.
The BA horizon has hue of 10YR or 7.5YR, value of 3 or 4 moist, 3 through 6 dry, and chroma of 2 through 6 moist or dry. It has 20 to 70 percent pebble-size weathered sandstone fragments. Texture is loam or silt loam.
The Bw horizon has value of 3 or 4 moist, 4 to 6 dry and chroma of 3 to 6 dry and moist. It is silt loam or loam in the fine-earth fraction.
COMPETING SERIES: There are no competing series. Similar soils in other families are the Bear Prairie, Calawah, Cinebar, Elochoman, Le Bar, Lytell, Mossyrock, Newaukum, Quillayute and Trouter series. Bear Prairie, Mossyrock and Quillayute soils have an umbric epipedon more than 20 inches thick. Calawah, Cinebar, and La Bar soils lack rock fragments in the particle-size control section. Elochoman soils are 27 to 35 percent clay and 0 to 15 percent coarse fragments in the particle-size control section. In addition, Cinebar, Mossyrock, Newaukum and Trouter soils have a xeric moisture regime. Newaukum soils have 5 to 30 percent hard rock fragments in the particle-size control section. Lytell soils have firm shot-sized concretions in the upper part of the particle-size control section, moderate or strong structure in the Bw horizon and 27 to 35 percent apparent clay in the control section. Trouter soils also have a lithic contact at 20 to 40 inches.
GEOGRAPHIC SETTING: Zenker soils are on colluvial mountain slopes deeply incised by many small drainageways forming a parallel pattern. Slopes are 8 to 90 percent. Elevation ranges from 50 to 1,700 feet. These soils formed from sandstone. The climate is characterized by cool, wet winters and relatively cool summers. The average annual precipitation ranges from 70 to 120 inches. The average January temperature is 37 degrees F.; the average July temperature is 62 degrees F.; and the average annual temperature is 46 to 50 degrees F. The growing season (28 F.) is 200 to 240 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Elochoman and Lytell soils. Elochoman soils are less than 15 percent sand and 0 to 15 percent coarse fragments in the particle-size control section. Lytell soils have 27 to 35 percent clay in the particle-size control section.
DRAINAGE AND PERMEABILITY: Well drained; moderate to rapid runoff; moderate permeability.
USE AND VEGETATION: Timber production. Native vegetation is mostly Douglas-fir and western hemlock and minor amounts of red alder, western redcedar, Sitka spruce, and bigleaf maple with an understory of vine maple, western swordfern, Oregongrape, salmonberry, western brackenfern, red elderberry, salal, red huckleberry, Oregon oxalis and starflower.
DISTRIBUTION AND EXTENT: Coastal mountains of southwestern Washington. Series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Wahkiakum County, Washington, 1976.
REMARKS: Diagnostic horizons and features recognized in this pedon are an umbric epipedon from the mineral surface to 17 inches and a cambic horizon from 17 to 60 inches. This description reflects a change in classification based on amendment 16. The particle-size control section has an estimated moist bulk density of less than 0.90 g/cc, volcanic glass content of 30 to 60 percent, acid-oxalate extractable aluminum plus one-half iron of more than 1 percent.
ADDITIONAL DATA: Riverside Laboratory data is available for this soil, sample number R75-123. Organic carbon estimates are based on data from the Elochoman series and are available at the National Soil Survey Laboratory, Lincoln, NE- sample number S77WA25-6.
REMARKS: Classification only changed 4/94 because of recent amendments to Soil Taxonomy.