LOCATION PILCHUCK WA+OREstablished Series
TAXONOMIC CLASS: Mixed, mesic Dystric Xeropsamments
TYPICAL PEDON: Pilchuck fine sand - forested. (Colors are for moist soil unless otherwise noted.)
A--0 to 20 inches; very dark gray (10YR 3/1) fine sand, dark gray (2.5Y 4/1) dry; single grain; loose, nonsticky and nonplastic; few roots; many very fine irregular pores; neutral (pH 6.6); clear smooth boundary. (0 to 23 inches thick)
C1--20 to 25 inches; dark grayish brown (2.5Y 4/2) loamy fine sand, gray (10YR 5/1) dry; single grain; loose, nonsticky and nonplastic; few roots; many very fine irregular pores; neutral (pH 6.6); abrupt wavy boundary. (0 to 48 inches thick)
C2--25 to 30 inches; very dark gray (10YR 3/1) and dark gray (10YR 4/1) fine sand, dark gray (10YR 4/1) dry; single grain; loose, nonsticky and nonplastic; few roots; many very fine irregular pores; neutral (pH 6.6); abrupt wavy boundary. (0 to 48 inches thick)
C3--30 to 38 inches; dark gray (10YR 4/1) loamy fine sand, grayish brown (10YR 5/2) dry; single grain; loose, nonsticky and nonplastic; few roots; many very fine irregular pores; slightly acid (pH 6.4); abrupt wavy boundary. (0 to 9 inches thick)
C4--38 to 60 inches; black (10YR 2/1) gravelly sand, very dark gray (10YR 3/1) dry; single grain; loose, nonsticky and nonplastic; few roots; many very fine irregular pores; neutral (pH 6.6).
TYPE LOCATION: King County, Washington; 650 feet north, 800 feet west of southeast corner, sec. 28, T. 21 N., R. 5 E.
RANGE IN CHARACTERISTICS: These soils are usually moist but are dry in the moisture control section for 60 to 75 consecutive days following summer solstice. The average annual soil temperature at a depth of 20 inches ranges from 47 to 53 degrees F. The particle-size control section is sand, fine sand or loamy fine sand. Rock fragments in the control section range from 0 to 15 percent by weighted average. These soils have an irregular decrease in organic carbon. Reaction is neutral to moderately acid throughout. Some pedons have weak granular structure in the A horizon and are structureless below or are structureless throughout. The upper 40 inches of the pedon has hue of 10YR or 2.5Y, value of 2 to 5 moist, 3 to 6 dry, and chroma of 1 to 3 moist or dry. Textures are loamy sand, loamy fine sand, fine sand or medium sand, and include gravelly sand in some subhorizon in the lower part of the control section of some pedons. The surface 5 to 9 inches is fine sandy loam or sandy loam in some pedons. The subhorizons below the control section have similar color and texture ranges, but range to very gravelly or extremely cobbly.
COMPETING SERIES: These are the Birdsview and Greenwater series. The Indianola, and Keystone series have similar classifications. All of these soils have a regular decrease in organic carbon. In addition, Birdsview soils are dry for 45 to 60 consecutive days following summer solstice. Greenwater soils have 5 to 25 percent ash and pumice in the particle-size control section. Keystone soils are dry for 75 to 90 consecutive days following summer solstice.
GEOGRAPHIC SETTING: Pilchuck soils are on flood plains at elevations of about 10 to 800 feet. The soils formed in recent sandy and gravelly alluvium. Slopes are 0 to 8 percent. The average annual precipitation is 35 to 60 inches. The average January temperature is 37 degrees F., average July temperature is 62 degrees F., and average annual temperature is about 50 degrees F. The frost-free season is about 160 to 210 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Briscot, Camas, Newberg, Puyallup, Renton, and Sultan soils. Briscot and Newberg soils are coarse-loamy. Camas soils are sandy-skeletal. Puyallup and Renton soils are coarse-loamy over sandy or sandy-skeletal. In addition, Briscot and Renton soils have an aquic moisture regime. Puyallup and Newberg soils have a mollic epipedon. Sultan soils are fine-silty. All these soils are on flood plains.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained; very slow runoff; rapid permeability; subject frequent or occasional flooding unless protected. An apparent water table is at its uppermost limit from November to April.
USE AND VEGETATION: These soils are used mostly for pasture or woodland. Native vegetation is Douglas-fir, western hemlock, western redcedar, bigleaf maple, black cottonwood, and red alder with an understory of vine maple, western swordfern, salmonberry, common snowberry, trillium, stinging nettle, bedstraw, Oregon oxalis, western brackenfern, and false-Solomon's-seal.
DISTRIBUTION AND EXTENT: Western Washington and Oregon; MLRA 2. The series is moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Snohomish County, Washington, 1938.
REMARKS: Diagnostic horizon and features recognized in this pedon are:
Ochric epipedon
Particle-size control section - the zone from 10 to 40 inches that is sandy throughout and is assumed to have an irregular decrease in organic carbon.
ADDITIONAL DATA: Characterization data is available from one pedon in Marion County, Oregon: soil survey sample # S99OR-047-001, NSSL, Lincoln, NE, 5/01. This sample pedon is a taxadjunct to the series.