LOCATION BOW WAEstablished Series
TAXONOMIC CLASS: Ashy over clayey, amorphic over smectitic, nonacid, mesic Typic Vitraquands
TYPICAL PEDON: Bow gravelly loam - pasture (colors are for moist soil unless otherwise stated. All textures are apparent field textures.)
Ap--0 to 7 inches; dark brown (10YR 3/3) gravelly loam, pale brown (10YR 6/3) dry; moderate fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine discontinuous pores; 20 percent pebbles, 10 percent cobbles; neutral (pH 6.6); clear irregular boundary. (3 to 9 inches thick)
Bw--7 to 16 inches; dark brown (7.5YR 4/4) very gravelly loam, light yellowish brown (10YR 6/4) dry; common fine prominent gray (5Y 6/1) mottles; moderate medium and fine subangular blocky structure; soft, very friable, nonsticky and nonplastic, weakly smeary; many very fine and common fine roots; common very fine discontinuous pores; 45 percent pebbles and 5 percent cobbles; neutral (pH 6.6); abrupt wavy boundary. (5 to 15 inches thick)
E--16 to 17 inches; grayish brown (2.5Y 5/2) very gravelly sandy loam, light gray (5Y 7/1) dry; common medium prominent strong brown (7.5YR 5/6) mottles; massive; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; few very fine discontinuous pores; 40 percent pebbles; neutral (pH 6.6); abrupt irregular boundary. (0 to 4 inches thick)
2E/B--17 to 23 inches; (E part) light olive gray (5Y 6/2) silt loam, white (5Y 8/1) dry; (B part) grayish brown (2.5Y 5/2) clay loam, light brownish gray (2.5Y 6/2) dry with common medium prominent yellowish brown (10YR 5/6) mottles; moderate medium subangular blocky structure; hard, firm, sticky and plastic; E part consists of tongues 1 to 3cm thick and makes up 60 percent of the horizon; common very fine and fine roots; few very fine discontinuous pores; 10 percent pebbles; slightly acid (pH 6.1); clear wavy boundary. (0 to 10 inches thick)
2B/E--23 to 31 inches; (B part) olive gray (5Y 5/2) silty clay, light brownish gray (2.5Y 6/2) dry; (E part) tongues of light olive gray (5Y 6/2) silt loam, white (5Y 8/1) dry; tongues consist of 40 percent of the horizon and are 0.5 to 1 cm thick; strong medium prismatic structure parting to strong medium angular blocky; hard, very firm, sticky and plastic; common very fine roots; few very fine continuous pores; common thin clay films on faces of peds and in pores; 5 percent pebbles; slightly acid (pH 6.1): gradual wavy boundary. (5 to 12 inches thick)
2Btg1--31 to 48 inches; olive gray (5Y 4/2) silty clay, gray (5Y 6/1) dry; strong medium and coarse prismatic structure parting to strong medium subangular blocky; very hard, very firm, sticky and plastic; few very fine roots; few very fine and fine continuous pores; many thin clay films on faces of peds and lining pores; common medium prominent dark brown (7.5YR 4/4) mottles and very dark brown (10YR 2/2) stains on ped faces; 5 percent pebbles; tongues of light olive gray (5Y 6/2) silt loam white (5Y 8/1) dry 2 to 10 mm thick on faces of some peds extends to a depth of 36 inches; interfingering of E material in root channels continues to a depth of 40 inches; neutral (pH 6.6); gradual irregular boundary. (10 to 30 inches thick)
2Btg2--48 to 60 inches; olive gray (5Y 4/2) silty clay, gray (5Y 6/1) dry; moderate coarse prismatic structure; very hard, very firm, sticky and plastic; few very fine roots; few very fine and fine continuous pores; many thin clay films on faces of peds and lining pores; 5 percent pebbles; few medium prominent dark brown (7.5YR 4/4) and very dark brown (10YR 2/2) stains on faces of peds; neutral (pH 6.6).
TYPE LOCATION: Skagit County, Washington about 4 miles west of Burlington; 2,400 feet north and 80 feet west of the southeast corner, sec. 29, T. 35 N., R. 3 E.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 50 to 54 degrees F. Thickness of the volcanic ash influence is l0 to 17 inches. Depth to the argillic horizon is 14 to 27 inches. Clay content in the argillic horizon averages 35 to 50 percent. Reaction is slightly acid or neutral throughout.
The A horizon has hue of 7.5YR or 10YR, value of 2 or 3 moist, 4 through 6 dry, and chroma of 2 to 4 moist or dry.
The Bw horizon has hue of 7.5YR or 10YR, value of 4 or 5, and chroma of 3 through 5. Texture is gravelly silt loam, gravelly loam, gravelly sandy loam, very gravelly loam, or very gravelly sandy loam. It contains 15 to 50 percent coarse fragments.
The E horizon has value of 4 through 6 moist, 6 through 8 dry, and chroma of 1 or 2 moist and dry. It is loamy sand, sandy loam, gravelly sandy loam, gravelly loamy sand, very gravelly sandy loam, or very gravelly loamy sand.
The E part of the E/B horizon is silt loam, loam or sandy loam. The Bt part has textures of clay loam, or silty clay loam. The E portion has value of 4 through 6 moist, 6 through 8 dry, and chroma of 1 or 2 moist and dry. The Bt portion has hue of 2.5Y or 5Y, value of 4 or 5 moist, 6 or 7 dry, and chroma of 1 or 2 moist and dry. This horizon contains 0 to 15 percent coarse fragments.
The B/E horizon has textures of silty clay loam, silty clay, or clay. The Bt portion has hue of 2.5Y or 5Y, value of 4 or 5 moist, 6 or 7 dry, and chroma of 1 or 2 moist or dry. The coating (E part) of this horizon has value of 4, 5, or 6 moist, 6 through 8 dry, and chroma of 1 or 2 moist and dry. This horizon contains 0 to 5 percent coarse fragments.
The Btg horizon has hue of 2.5Y or 5Y, value of 4 or 5 moist, 6 or 7 dry, and chroma of 1 or 2 moist or dry. Texture is silty clay or clay. This horizon contains 0 to 5 percent coarse fragments.
COMPETING SERIES: These are the Coveland, Coweeman, and Hardscrabble. Coveland soils have a surface layer with umbric colors 7 to 9-1/2 inches thick and lack the influence of volcanic ash. Coweeman and Hardscrabble soils lack an E horizon and an E/B horizon. In addition, Hardscrabble soils are very strongly acid throughout the Bt horizon.
GEOGRAPHIC SETTING: Bow soils are on glaciated terraces and till plains at elevations near sea level to 400 feet. Slopes are 0 to 45 percent. These soils formed in gravelly glacial drift over lacustrine material with a mantle of volcanic ash. Average annual precipitation is 20 to 40 inches. Mean January temperature is about 38 degrees F, mean July temperature is about 62 degrees F, and mean annual temperature is about 50 degrees F. The frost-free season is 170 to 220 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Catla and Clallam series and the competing Coveland series. Catla and Clallam soils have a paralithic contact within 40 inches of the surface.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; slow runoff, slow permeability.
USE AND VEGETATION: Used for pasture, cropland, woodland, and homesites. Native vegetation is Douglas-fir, western redcedar and red alder, with an understory of creambush oceanspray, western swordfern, salal, and Oregon-grape.
DISTRIBUTION AND EXTENT: Northwestern Washington. This series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Pierce County, Washington, 1939.
REMARKS: Classification only changed 4/94 because of recent amendments to Soil Taxonomy. 0 to 17 inch depths meets criteria for andic soil properties. Diagnostic horizons and features recognized in this pedon are an ochric epipedon, from the surface to 7 inches, an albic horizon that interfingers into an argillic horizon from 16 to 31 inches, and an argillic horizon from 31 to 60 inches.