LOCATION SNAKELUM WAEstablished Series
TAXONOMIC CLASS: Sandy, isotic, mesic Ultic Haploxerolls
TYPICAL PEDON: Snakelum coarse sandy loam, grassland, on a south-facing glacial outwash plain with a slope of 5 percent and elevation of 60 meters. Colors are for dry soil unless otherwise noted.
A--0 to 25 cm; very dark brown (10YR 2/2) coarse sandy loam, black (10YR 2/1) moist; moderate fine granular structure; slightly hard, friable, nonsticky and nonplastic; high in organic matter; strongly acid to moderately acid; abrupt smooth boundary. (15 to 41 cm thick)
AB--25 to 46 cm; dark grayish brown (10YR 4/2) sandy loam, very dark brown (10YR 2/2) moist; weak fine granular structure; hard, firm, nonsticky and nonplastic; strongly acid to moderately acid; clear smooth boundary. (10 to 30 cm thick)
Bw--46 to 60 cm; light brownish gray (10YR 6/2) sandy loam; dark grayish brown (10YR 4/2) moist; few faint yellow and brown mottles; massive; hard, very firm, nonsticky and nonplastic; moderately acid; clear smooth boundary. (15 to 30 cm thick)
2BC--60 to 122 cm; light brownish gray (10YR 6/2) loamy coarse sand, dark grayish brown (10YR 4/2) moist; single grain, loose, nonsticky and nonplastic; slightly acid; gradual smooth boundary (30 to 91 cm thick)
2C--122 to 152 cm; coarse sand; variegated parent material colors; single grain, loose, nonsticky and nonplastic; few gravel; slightly acid.
TYPE LOCATION: Island County, Washington; Smith Prairie, 3 miles east of Coupeville; 200 meters north, 480 meters west of the southeast corner of section 1, T. 31N., R. 1E. Willamette Baseline Meridian. Latitude 48 deg, 11 min, 51 sec north, Longitude 122 deg, 37 min, 20 seconds west.
RANGE IN CHARACTERISTICS: Depths to diagnostic horizons and features start from the mineral soil surface.
Soil moisture control section - dry for 75 to 90 consecutive days following summer solstice
Mean annual soil temperature - 10 to 12 degrees C.
Mollic epipedon - 25 to 50 cm thick.
Reaction - slightly acid or strongly acid.
Depth to sand or loamy sand textures - 40 to 60 cm
Particle-size control section:
Rock Fragments - 0 to 5 percent gravel
A horizon
Value - 2 to 4 dry and 1 or 2 moist
Chroma - 1 or 2 moist and dry
AB horizon
Value - 4 or 5 dry and 2 or 3 moist
Chroma - 2 or 3 moist and dry
Texture - SL or FSL
Clay content - 5 to 15 percent
Bw horizon
Value - 5 to 7 dry and 4 or 5 moist
Chroma - 2 or 3 moist and dry
Texture - SL or FSL
Clay content - 5 to 15 percent
2BC horizon
Value - 5 to 7 dry and 4 or 5 moist
Chroma - 2 or 3 moist and dry
Texture - LCOS, LS, or COS
Clay content - 2 to 6 percent
2C horizon
Hue - 10YR to 5Y
Value - 4 to 7 dry and 4 to 6 moist
Chroma - 1 to 3 moist and dry
Texture - COS or LCOS
Clay content - 2 to 5 percent
COMPETING SERIES: This is the Hobohill soils. Hobohill soils lack a cambic horizon and are dry in all parts of the moisture control section for 90 to 105 consecutive days following the summer solstice.
GEOGRAPHIC SETTING: Snakelum soils formed in glacial outwash or other sandy drift on braided glacial outwash plains from near sea level to about 185 meters. Slopes are 0 to 15 percent. These soils are in a mild marine climate with mild, wet winters and cool, dry summers. The average annual precipitation is 457 to 635 mm. The mean January temperature is about 5 degrees C, the mean July temperature is about 13 degrees C, and the mean annual temperature is about 10 degrees C. The frost-free season is about 230 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Hoypus soils and San Juan soils. Hoypus soils lack a mollic epipedon and have a sandy-skeletal particle-size control section. Hoypus soils form under forest canopy on similar landscape positions. San Juan soils are pachic and formed on dunes and hillslopes of glacial outwash plains.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat excessively drained. Saturated hydraulic conductivity is high in the A, AB and Bw horizons and very high in the 2BC and 2C horizons.
USE AND VEGETATION: Snakelum soils are used for home sites, crop production, and livestock grazing. Potential natural vegetation may include an overstory of scattered Oregon white oak and Douglas fir but is primarily prairie grass vegetation including Roemers fescue, western brackenfern, baldhip rose, common snowberry, and trailing blackberry.
DISTRIBUTION AND EXTENT: Whidbey Island in the Puget Sound of western Washington; MLRA 2. The series is of small extent.
MLRA OFFICE RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Island County, Washington, 1950.
REMARKS: Diagnostic horizon and features recognized in this pedon include:
Mollic epipedon - the zone from the surface to 46 cm (A and AB horizons)
Cambic horizon - the zone from 46 to 60 cm (Bw)
Particle-size control section - the zone from 25 to 100 cm
This revision (5/2006) includes a change in classification based on field investigations and lab data from similar soils. The previous classification was coarse-loamy, mixed, superactive, mesic Humic Dystroxerepts.