LOCATION MITCHELLBAY WAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Aquultic Haploxeralfs
TYPICAL PEDON: Mitchellbay gravelly sandy loam, forested, on a gently sloping glacial drift plain at 120 feet elevation. (Colors are for moist soil unless otherwise noted. When described on October 17, 2003 the soil was dry throughout.)
Oi--0 to 1 inch, slightly decomposed needles and twigs.
A--1 to 6 inches, very dark grayish brown (10YR 3/2) gravelly sandy loam, dark grayish brown (10YR 4/2) dry; moderate medium granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine and fine, many medium and coarse roots, many very fine and fine irregular and interstitial pores; 15 percent gravel; very strongly acid (pH 5.0); clear wavy boundary. (3 to 10 inches thick)
Bw--6 to 15 inches, dark yellowish brown (10YR 4/4) gravelly sandy loam, yellowish brown (10YR 5/4) dry; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine, many medium to coarse roots, many very fine and fine irregular and interstitial pores; 15 percent gravel; moderately acid (pH 5.6); clear wavy boundary. (6 to 10 inches thick)
E--15 to 20 inches, dark grayish brown (10YR 4/2) sandy loam, light brownish gray (10YR 6/2) dry; moderate medium prismatic structure; moderately hard, firm, slightly sticky and slightly plastic; common very fine to medium roots; common very fine irregular and tubular pores; few faint dark yellowish brown (10YR 4/6) iron masses throughout; 10 percent gravel; moderately acid (pH 6.0); gradual wavy boundary. (4 to 11 inches thick)
Btg1--20 to 26 inches, brown (10YR 4/3) loam, yellowish brown (10YR 5/4) dry; strong medium prismatic structure; very hard, extremely firm, moderately sticky and moderately plastic; common very fine and fine, few medium roots between peds; common very fine irregular and tubular pores; many prominent dark yellowish brown (10YR 4/6) iron masses throughout; few faint clay films on faces of peds; few distinct very dark grayish brown (10YR 3/2) organic stains on faces of peds; 5 percent fine gravel; slightly acid (pH 6.4); gradual wavy boundary. (8 to 16 inches thick)
Btg2--26 to 38 inches, brown (10YR 4/3) loam, yellowish brown (10YR 5/4) dry; strong coarse prismatic structure; very hard, extremely firm, moderately sticky and moderately plastic; common very fine and fine, few medium roots between peds; common very fine irregular and tubular pores; many prominent dark yellowish brown (10YR 4/6) iron masses throughout; few faint clay films on faces of peds; few distinct very dark grayish brown (10YR 3/2) organic stains on faces of peds; 5 percent fine gravel; slightly acid (pH 6.4); gradual wavy boundary. (8 to 16 inches thick)
Cd--38 to 60 inches, brown (10YR 5/3) loam, pale brown (10YR 6/3) dry; massive; very hard, extremely firm, slightly sticky and slightly plastic; few very fine roots greater than 4 inches apart between cracks; neutral (pH 7.3).
TYPE LOCATION: San Juan County, Washington; located about 1,900 feet south and 1,017 east of the northwest corner of sec. 19, T. 36 N., R. 3 W. Willamette Meridian; USGS Friday Harbor NW quarter quadrangle; lat. 48 degrees 36 minutes 12 seconds N. and long. 123 degrees 2 minutes 37 seconds W.
RANGE IN CHARACTERISTICS: Depths to diagnostic horizons and features start from the mineral soil surface.
Mean annual soil temperature - 48 to 50 degrees F.
Moisture control section - dry 60 to 75 days following the summer solstice
Depth to redoximorphic features - 9 to 18 inches
Depth to densic contact - 20 to 40 inches
Particle-size control section:
Clay content - 18 to 35 percent
A horizon
Value - 2 or 3 moist, 4 or 5 dry
Chroma - 2 or 3 moist and dry
Bw horizon
Value - 3 or 4 moist, 4 or 5 dry
Chroma - 2 or 3 moist and dry
Texture - SL or L
Clay content - 8 to 18 percent
Rock fragments - 0 to 25 percent gravel, 0 to 10 percent cobbles, 0 to 35 percent total
E horizon
Value - 4 or 5 moist, 5 to 7 dry
Chroma - 1 to 2 moist and dry
Texture - SL or L
Clay content - 4 to 12 percent
Rock fragments - 0 to 15 percent gravel
Btg horizons
Hue - 10YR or 2.5Y
Value - 3 to 5 moist, 5 to 7 dry
Chroma - 2 or 3 moist and dry
Texture - L, SIL, or SICL
Clay content - 18 to 35 percent
Rock fragments - 0 to 15 percent fine gravel
Cd horizon
Value - 3 to 5 moist, 4 to 6 dry
Chroma - 2 or 3 moist and dry
Texture - L, SL, or SIL
Clay content - 12 to 27 percent
Rock fragments - 0 to 15 percent fine gravel
COMPETING SERIES: These are the Deadmanbay, Doolyville, Killebrew, Quatama and Stockel series. Deadmanbay soils have a densic contact between 40 and 60 inches. Doolyville soils are very deep, and are 30 to 50 cm to redoximorphic features. Killebrew soils are dry in the moisture control section for 75 to 90 days, have a massive E horizon, with a bulk density of more than 1.8 g/cm3, and a hard dry rupture resistance. Quatama soils do not have redoximorphic features above 15 inches, an albic horizon, or a densic contact. Stockel soils do not have an albic horizon or a densic contact. The Wellsdale series has similar classification but an active cation-exchange activity class. Wellsdale soils do not have redoximorphic features above 20 inches, an albic horizon, or a densic contact.
GEOGRAPHIC SETTING: Mitchellbay soils are in valleys of glacial drift plains. Slopes range from 0 to 25 percent. These soils formed in glacial drift over dense glaciomarine deposits. Elevations are 0 to 500 feet. The climate is characterized by warm dry summers and mild moist winters. The mean annual precipitation is 25 to 40 inches. Mean annual temperature is 48 to 50 degrees F. The frost-free period is about 200 to 240 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Coupeville, Coveland, and Bazal soils. Coupeville soils are in depressions within valleys of glacial drift plains and have aquic conditions to the surface. Coveland soils are in valleys of glacial drift plains and have a densic contact between 40 and 60 inches. Bazal soils are in valleys of glacial drift plains and have aquic conditions to the soil surface.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat poorly drained. Saturated hydraulic conductivity is high in the upper part (A, Bw, and E horizons) and moderately high to low in the lower part (Btg and Cd horizons).
USE AND VEGETATION: These soils are used for pasture, forage crop production, and forestry. Potential natural vegetation consists of western redcedar, bigleaf maple, Douglas-fir, grand fir, red alder, swordfern, deer fern, salal, stinging nettle, gooseberry, and snowberry.
DISTRIBUTION AND EXTENT: Northwest Washington; MLRA A2, Northern Part. Series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: San Juan County, Washington, 2006.
REMARKS: Diagnostic horizons and features recognized in this pedon include:
Ochric epipedon - 1 to 6 inches (A horizon)
Cambic horizon - 6 to 15 inches (Bw horizon)
Albic horizon - 15 to 20 inches (E horizon)
Argillic horizon - 20 to 38 inches (Btg horizon)
Densic contact - 38 inches (upper boundary of Cd horizon)
Particle-size control section - 20 to 38 inches (argillic horizon)
Depth to redoximorphic features - 15 inches (depleted matrix with a chroma of 2 or less and iron masses)
ADDITIONAL DATA: NSSL pedon number 03N0236, NASIS user pedon ID # 03WA055006