LOCATION SAN JUAN WAEstablished Series
TAXONOMIC CLASS: Sandy, isotic, mesic Pachic Ultic Haploxerolls
TYPICAL PEDON: San Juan sandy loam rangeland, on a south facing glacial outwash plain with a slope of 3 percent and elevation of 65 feet. When described on October 22, 2003 the soil was moist to 10 inches and dry below. Colors are for moist soil unless otherwise noted.
A1--0 to 4 inches; black (10YR 2/1) sandy loam, dark gray (10YR 4/1) dry; weak fine granular structure; soft, very friable, non-sticky and non-plastic; many very fine and fine roots; many very fine and fine irregular pores; strongly acid (pH 5.1); abrupt smooth boundary. (4 to 8 inches thick)
A2--4 to 13 inches; black (10YR 2/1) sandy loam, dark gray (10YR 4/1) dry; moderate medium subangular blocky structure; soft, very friable, non-sticky and non-plastic; many very fine and fine roots; many very fine and fine irregular pores; 5 percent fine gravel; moderately acid (pH 5.8); abrupt smooth boundary. (8 to 12 inches thick)
A3--13 to 19 inches; black (10YR 2/1) sandy loam, dark gray (10YR 4/1) dry; moderate medium subangular blocky structure; soft, very friable, non-sticky and non-plastic; common very fine and fine roots; many very fine and fine irregular pores; 5 percent fine gravel; slightly acid (pH 6.4); clear wavy boundary. (6 to 10 inches thick)
Bw--19 to 27 inches; very dark brown (10YR 2/2) gravelly loamy coarse sand, brown (10YR 4/3) dry; weak medium subangular blocky structure; soft, very friable, non-sticky and non-plastic; few very fine roots; many very fine and fine interstitial pores; 30 percent gravel; slightly acid (pH 6.5); clear wavy boundary. (4 to 10 inches thick)
C1--27 to 41 inches; very gravelly coarse sand, variegated parent material colors, 40 percent dark, 40 percent light, and 20 percent intermediate mineral colors; single grain; loose, non-sticky and non-plastic; few very fine roots; many very fine and fine interstitial pores; 55 percent gravel; neutral (pH 6.8); clear wavy boundary. (4 to 18 inches thick)
C2--41 to 62 inches; extremely gravelly coarse sand, variegated parent material colors, 40 percent dark, 40 percent light, and 20 percent intermediate mineral colors; single grain; loose, non-sticky and non-plastic; many very fine and fine interstitial pores; 75 percent gravel and 5 percent cobbles; neutral (pH 6.7); clear wavy boundary. (4 to 24 inches thick)
C3--62 to 70 inches; extremely gravelly coarse sand, variegated parent material colors, 40 percent dark, 40 percent light, and 20 percent intermediate mineral colors; single grain; loose, non-sticky and non-plastic; many very fine and fine interstitial pores; 75 percent gravel; neutral (pH 6.9). (0 to 12 inches thick)
TYPE LOCATION: San Juan County, Washington, about 5 miles south of the town of Friday Harbor on American Camp portion of San Juan Island National Historical Park; about 590 feet south and 2,000 feet west of the northeast corner of Section 12, T. 34 N., R. 3 W. Willamette Baseline Meridian; USGS False Bay NE quarter quadrangle; Latitude 48 degrees 27 minutes and 43 seconds North, Longitude 123 degrees 0 minutes and 14 seconds West.
RANGE IN CHARACTERISTICS: Depths to diagnostic horizons and features start from the mineral soil surface.
Average annual soil temperature - 50 to 54 degrees F.
Soil moisture control section - dry 75 to 90 days following summer solstice
Mollic epipedon thickness - 20 to 32 inches
Base saturation by ammonium acetate - greater than 50 percent within the epipedon
Base saturation by sum of cations - less than 75 percent from 10 to 30 inches
Volcanic glass - less than 5 percent throughout
Particle size control section:
Clay Content - 0 to 12 percent
Rock fragments - 0 to 35 percent in the A2 and A3 horizons, 15 to 60 percent in the Bw horizon, and 35 to 85 percent in the C horizons with a weighted average between 15 and 35 percent
A1 horizon
Value - 2 or 3 moist, 3 or 4 dry
Chroma - 1 or 2 moist and dry
Clay content - 5 to 12 percent
Rock fragments - 0 to 15 percent gravel
A2 and A3 horizons
Value - 2 or 3 moist, 3 or 4 dry
Chroma - 1 or 2 moist and dry
Reaction - moderately acid or slightly acid
Texture - SL, L, or LS
Clay content - 2 to 12 percent
Rock fragments - 0 to 35 percent gravel, 0 to 5 percent cobbles, 0 to 35 percent total
Bw horizon
Hue - 10YR or 7.5YR
Value - 2 or 3 moist, 3 or 4 dry
Chroma - 1 to 3 moist and dry
Reaction - slightly acid or moderately acid
Texture - LCOS, SL, or LS
Clay content - 0 to 8 percent
Rock fragments - 15 to 60 percent gravel, 0 to 5 percent cobbles, 15 to 60 percent total
C horizons
Hue - 2.5Y or variegated mineral colors
Value - 3 or 4 moist, 4 or 5 dry
Chroma - 2 or 3 moist and dry
Reaction - slightly acid or neutral
Texture - COS, LS, or LCOS
Clay content - 0 to 5 percent
Rock fragments - 35 to 80 percent gravel, 0 to 15 percent cobbles, 35 to 85 percent total
COMPETING SERIES: There are no competing series in this family.
GEOGRAPHIC SETTING: San Juan soils are on dunes, hillslopes, and glacial outwash plains with slopes of 0 to 60 percent and elevations from 0 to about 300 feet. These soils formed in eolian sands over glacial outwash. The maritime climate is characterized by warm dry summers and mild moist winters. Average annual precipitation is 18 to 30 inches. Average annual temperature is 48 to 50 degrees F. The frost-free period is 200 to 240 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ebeys, Hoypus, Keystone, Pilepoint, and Snakelum soils, all of which also occur on hillslopes and glacial outwash plains. Ebeys soils are formed entirely in well sorted eolian and glacial outwash sands with no appreciable gravel or cobbles. Hoypus soils lack a mollic epipedon and have a sandy-skeletal particle-size control section. Keystone soils lack a mollic epipedon and are formed in well sorted eolian and glacial outwash sands with no appreciable gravel or cobbles. Pilepoint soils have an argillic horizon, are 20 to 40 inches to a densic contact, and have redoximorphic features at 20 to 40 inches. Snakelum soils are not pachic and formed in dense stratified glacial outwash and drift.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat excessively drained. Saturated hydraulic conductivity is high to very high through the profile.
USE AND VEGETATION: Mainly used for wildlife habitat, pasture, and hay. Potential natural vegetation may include an overstory of scattered Oregon white oak and Douglas-fir but is primarily prairie vegetation including Roemers fescue, western brackenfern, baldhip rose, common snowberry, and trailing blackberry.
DISTRIBUTION AND EXTENT: Northwest Washington; MLRA 2, Northern part. Series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: 1910 Reconnaissance survey of the western part of Puget Sound Basin, Washington.
REMARKS: Diagnostic horizons and features recognized in this pedon include:
Mollic epipedon - 0 to 27 inches (A1, A2, A3, and Bw horizons)
Particle-size control section - the zone from 10 to 40 inches
Base saturation by sum of cations - less than 30 percent from 10 to 30 inches
ADDITIONAL DATA: Characterization pedon sampled at the type location, NSSL pedon number 04N0409. Reference sample, NSSL pedon number 03N0239