LOCATION KILLEBREW WAEstablished Series
TYPICAL PEDON: Killebrew sandy loam, forested, on a gently sloping glacial outwash plain at 67 m elevation. (Colors are for dry soil unless otherwise noted. When described on October 5, 2005 the soil was dry throughout.)
Oi--0 to 3 cm; slightly decomposed plant material; abrupt wavy boundary.
A--3 to 13 cm; very dark grayish brown (10YR 3/2) sandy loam, very dark brown (10YR 2/2) moist; weak fine subangular blocky structure; soft, very friable, nonsticky, nonplastic; many very fine and fine, common medium and coarse roots; many very fine and fine irregular pores; 10 percent gravel; very strongly acid (pH 5.0); clear wavy boundary.(8 to 24 cm thick)
Bw--13 to 23 cm; brown (7.5YR 5/4) sandy loam, brown (7.5YR 4/3) moist; weak medium subangular blocky structure; soft, very friable, slightly sticky, slightly plastic; many fine and medium roots; many very fine and fine irregular pores; 10 percent gravel; moderately acid (pH 5.6); clear wavy boundary. (8 to 25 cm thick)
E--23 to 43 cm; light brownish gray (2.5Y 6/2) gravelly sandy loam, grayish brown (2.5Y 5/2) moist; massive; hard, firm, nonsticky, nonplastic; few very fine roots; few very fine and fine irregular pores; many prominent yellowish brown (10YR 5/8), and dark yellowish brown (10YR 4/6) moist, iron-manganese masses in matrix; 20 percent gravel and 5 percent cobbles; moderately acid (pH 6.0); gradual wavy boundary. (10 to 20 cm thick)
2Btg--43 to 69 cm; light olive brown (2.5Y 5/4) silt loam, olive brown (2.5Y 4/4) dry; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic; few very fine roots in cracks; few very fine and fine tubular pores; many distinct light brownish gray (2.5Y 6/2) grayish brown (2.5Y 5/2) moist, iron depletions and many prominent yellowish brown (10YR 5/8) dark yellowish brown (10YR 4/6) moist, iron-manganese masses; 5 percent gravel; slightly acid (pH 6.4); clear wavy boundary.(15 to 30 cm thick)
2Cd--69 to 152 cm; light olive brown (2.5Y 5/3) loam, olive brown (2.5Y 4/3) moist; massive; hard, firm, slightly sticky, slightly plastic; no roots, 10 percent gravel; neutral (pH 7.3).
TYPE LOCATION: San Juan County, Washington; located about 600 meters south and 60 meters west of the northeast corner of sec. 34, T. 35 N., R. 2 W. Willamette Meridian; USGS Richardson NE quarter quadrangle; lat. 48 degrees 29 minutes 14 seconds N. and long. 122 degrees 54 minutes 38 seconds W.
RANGE IN CHARACTERISTICS: Depths to diagnostic horizons and features start from the mineral soil surface.
Mean annual soil temperature - 9 to 10 degrees C.
Moisture control section - dry 75 to 90 days following the summer solstice Depth to redoximorphic features - 23 to 46 cm
Depth to densic contact - 50 to 100 cm
Particle-size control section:
clay content - 18 to 35 percent
A horizon
Value - 2 or 3 moist, 3 to 5 dry
Chroma - 2 or 3 moist and dry
Bw horizon
Value - 3 or 4 moist, 4 or 5 dry
Chroma - 3 or 4 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
Bulk density - 1.8 to 1.9 g/cm3
Rock fragments - 0 to 25 percent gravel, 0 to 5 percent cobbles
Btg horizons
Hue - 10YR or 2.5Y
Value - 3 to 5 moist, 4 to 6 dry
Chroma - 2 to 4 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, Mitchellbay, Quatama, and Stockel series. Deadmanbay soils have a densic contact between 100 and 150 cm. Mitchellbay soils are dry in the moisture control section for 60 to 75 days, and have an E horizon which has moderate medium prismatic structure, bulk density of less than 1.8 g/cm3, and a moderately hard dry rupture resistance. Quatama soils do not have redoximorphic features above 38 cm, 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 50 cm, an albic horizon, or a densic contact.
GEOGRAPHIC SETTING: Killebrew soils are in valleys and on glacial drift plains. Slope ranges from 0 to 25 percent. These soils formed in glacial drift underlain by dense glaciomarine deposits. Elevations are 0 to 158 m. The climate is characterized by warm dry summers and mild moist winters. Mean annual precipitation is 457 to 762 mm. The average annual temperature is 9 to 10 degrees C. The frost-free period is about 200 to 240 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Coupeville, Coveland, and Bazal (T) soils. Coupeville soils are in depressions within valleys and glacial drift plains and have aquic conditions to the surface. Coveland soils are in valleys and glacial drift plains and have a densic contact between 100 and 150 cm. Bazal soils are in valleys and glacial drift plains and have aquic conditions to the soil surface.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat poorly drained. Saturated hydraulic conductivity is moderately rapid in the upper part (A and Bw horizons) and moderately slow to very slow in the lower part (E, Btg, and Cd horizons).
USE AND VEGETATION: Killebrew soils are used for timber production, wildlife habitat, forage crop production, and livestock grazing. Potential natural vegetation is Douglas-fir, madrone, lodgepole pine, oceanspray, baldhip rose, salal, Cascade Oregongrape, rattlesnake plantain, and bracken fern.
DISTRIBUTION AND EXTENT: Northwest Washington; MLRA A2, Northern Part. Series is of small 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
Albic horizon - 23 to 43 cm (E horizon)
Argillic horizon - 43 to 69 cm (Btg horizon)
Densic contact - 69 cm (upper boundary of Cd horizon)
Particle-size control section - 43 to 69 cm (argillic horizon)
Depth to redoximorphic features - 23 cm (depleted matrix with a chroma of 2 or less and iron-manganese concentrations)