LOCATION KEYSTONE           WA
Established Series
Rev. MPR/CAB/SBC
07/2007

KEYSTONE SERIES


The Keystone series consists of very deep, somewhat excessively drained soils formed in sandy glacial outwash on plains, hillslopes, kames, and moraines at elevations of near sea level to 60 meters. Slopes are 3 to 25 percent. Mean annual precipitation is about 610 mm. Mean annual temperature is about 9 degrees C.

TAXONOMIC CLASS: Isotic, mesic Dystric Xeropsamments

TYPICAL PEDON: Keystone sandy loam-forested, on an 8 percent slope. (Colors are for dry soil unless otherwise noted.)

Oi--0 to 3 cm; slightly decomposed plant material; clear smooth boundary.

A1--3 to 8 cm; dark grayish brown (10YR 4/2) sandy loam, black (10YR 2/1) moist; strong coarse granular structure; slightly hard, very friable, nonsticky, nonplastic; many very fine, fine, and medium roots; moderately acid (pH 5.7); clear wavy boundary.

A2--8 to 20 cm; brown (10YR 5/3) sandy loam, very dark grayish brown (10YR 3/2) moist; weak medium subangular blocky structure; slightly hard, very friable, nonsticky, nonplastic; many very fine, fine, and medium roots; 5 percent gravel; moderately acid (pH 5.6); clear wavy boundary. (Combined A horizon thickness is 13 to 24 cm)

Bw1--20 to 48 cm; light yellowish brown (2.5Y 6/4) loamy sand, olive brown (2.5Y 4/3) moist; single grain; loose, nonsticky, nonplastic; common fine and many medium and coarse roots; 5 percent gravel; strongly acid (pH 5.5); clear wavy boundary.

Bw2--48 to 86 cm; light yellowish brown (2.5Y 6/4) very gravelly loamy sand, light olive brown (2.5Y 5/3) moist; single grain; loose, nonsticky, nonplastic; few fine and medium roots; 25 percent gravel, 5 percent cobbles, and 5 percent stones; moderately acid (pH 6.0); clear wavy boundary. (Combined Bw horizon thickness is 30 to 68 cm)

C--86 to 150 cm; light yellowish brown (2.5Y 6/3) loamy sand, light olive brown (2.5Y 5/3) moist; massive; moderately hard, friable, nonsticky, nonplastic; slightly acid (pH 6.3); 5 percent gravel.

TYPE LOCATION: San Juan County, Washington; 114 meters south and 386 meters west of NE corner of section 22, T 35N, R 3W; Willamette Meridian; USGS Friday Harbor, Washington quadrangle; lat. 48 degrees, 31 minutes, 14 seconds N. and long. 123 degrees, 2 minutes, 40 seconds W.

RANGE IN CHARACTERISTICS: Depths to diagnostic horizons and features start from the mineral soil surface.

Average annual soil temperature - 10 to 11 degrees C.
Moisture control section - dry 75 to 90 days following summer solstice
Reaction - slightly acid to strongly acid
Particle size control section:
Clay content - 0 to 8 percent
Rock fragments - 0 to 35 percent gravel, 0 to 5 percent cobbles, 0 to 5 percent stones, and 0 to 35 percent total

A1 horizon
Hue - 10YR or 7.5YR
Value - 2 or 3 moist, 4 to 6 dry
Chroma - 1 to 3 moist and dry
Texture - FSL, SL, or LS
Clay content - 0 to 8 percent
Rock fragments - 0 to 15 percent gravel

A2 horizon
Hue - 10YR or 7.5YR
Value - 2 or 3 moist, 4 to 6 dry
Chroma - 1 to 3 moist and dry
Reaction - slightly acid or moderately acid
Texture - SL or LS
Clay content - 0 to 8 percent
Rock fragments - 0 to 35 percent gravel

Bw horizons
Hue - 10YR or 7.5YR
Value - 3 to 5 moist, 5 to 7 dry
Chroma - 2 to 5 moist and dry
Reaction - slightly acid to strongly acid
Texture - LS or S
Clay content - 0 to 5 percent
Rock fragments - 0 to 35 percent gravel, 0 to 5 percent cobbles, and 0 to 5 percent stones

C horizon
Hue - 10YR or 2.5Y
Value - 2 to 4 moist, 5 to 7 dry
Chroma - 2 to 4 moist and dry
Reaction - slightly acid or moderately acid
Texture - LS or COS
Clay content - 0 to 5 percent
Rock fragments - 0 to 35 percent gravel

COMPETING SERIES: These are the Birdsview, Greenwater, Indianola, and Pilchuck series. All of these soils are dry in the moisture control section less than 75 consecutive days following the summer solstice. In addition, Birdsview soils can have a frost free period of less than 200 days and mean annual soil temperature less than 10 degrees C. Greenwater soils have 5 to 25 percent volcanic ash and pumice in the control section. Pilchuck soils lack a B horizon, have a chroma of 2 or less throughout the control section, and have an irregular decrease in organic carbon with depth.

GEOGRAPHIC SETTING: Keystone soils formed in sandy glacial drift on glacial outwash plains, hillslopes, kames and moraines. Elevations are near sea level to 90 meters. Slopes are 3 to 25 percent. Mean annual precipitation ranges from 457 to 762 mm most of which falls as rain in the late fall, winter and early spring. Mean annual temperature is about 9 to 10 degrees C. The frost-free season is 200 to 240 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bow, Laconner, and Whidbey series. Bow and Laconner soils are on broad glaciated terraces and till plains. Bow soils are in a fine family and have an argillic horizon. Laconner soils are sandy-skeletal and have a densic contact at 25 to 40 cm. Whidbey and Keystone soils are in complex on similar landscape positions. Whidbey soils are in a loamy-skeletal family and are underlain by dense glacial till at a depth of 20 to 40 cm.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat excessively drained. Saturated hydraulic conductivity is very high throughout.

USE AND VEGETATION: Used for home sites, crop production, livestock grazing, and timber production. Potential natural vegetation consists of Douglas-fir, Pacific madrone, lodgepole pine, oceanspray, baldhip rose, salal, Cascade Oregongrape, rattlesnake plantain, and bracken fern.

DISTRIBUTION AND EXTENT: Northwestern Washington, MLRA A2. This series is of moderate extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon

SERIES ESTABLISHED: Island County, Washington, 1950.

REMARKS: Diagnostic horizon and other features:
Ochric epipedon
Particle size control section - 25 to 100 cm

This revision (5/2006) includes a new type location and a mineralogy class change from mixed to isotic, based on laboratory data.

ADDITIONAL DATA: NSSL pedon 04N0761


National Cooperative Soil Survey
U.S.A.