LOCATION LYALL WA

Established Series
Rev. CAB/SBC
06/2011

LYALL SERIES

The Lyall series consists of very deep, well drained soils formed in minor amounts of volcanic ash mixed with alluvium and reworked glacial drift on terraces, alluvial fans, valley walls, and debris cones. Slopes are 0 to 15 on terraces and alluvial fans and 15 to 65 percent on valley walls and debris cones. The mean annual precipitation is about 1,650 millimeters. The mean annual temperature is about 7 degrees C.

TAXONOMIC CLASS: Sandy-skeletal, isotic, frigid Vitrandic Dystroxerepts

TYPICAL PEDON: Lyall gravelly ashy sandy loam, on a valley wall landform with a SW facing slope of 30 percent at 535 meters elevation under coniferous forest vegetation. When described on September 28, 2007 the soil was moist in the upper 10 cm and dry below. (Colors are for moist soil unless otherwise noted.)

Oi--0 to 4 cm; slightly decomposed plant material; abrupt smooth boundary.

Oe--4 to 7 cm; moderately decomposed plant material; abrupt wavy boundary.

A--7 to 19 cm; very dark brown (10YR 2/2) gravelly ashy coarse sandy loam, dark grayish brown (10YR 4/2) dry; weak fine granular structure; soft, very friable, nonsticky, nonplastic; common very fine, fine, medium, and coarse roots throughout; 5 percent fine gravel and 15 percent medium and coarse gravel; strongly acid (pH 5.5); clear wavy boundary.

Bw1--19 to 44 cm; dark yellowish brown (10YR 4/4) very gravelly ashy coarse sandy loam, yellowish brown (10YR 5/4) dry; single grain; loose, nonsticky, nonplastic; common very fine, fine, medium, and coarse roots; 10 percent fine gravel, 30 percent medium and coarse gravel, and 5 percent cobbles; moderately acid (pH 5.7); clear wavy boundary.

Bw2--44 to 75 cm; dark yellowish brown (10YR 3/6) very gravelly loamy sand, yellowish brown (10YR 5/6) dry; single grain; loose, nonsticky, nonplastic; common very fine and fine and few medium and coarse roots; 10 percent fine gravel, 35 percent medium and coarse gravel, and 5 percent cobbles; moderately acid (pH 5.8); gradual wavy boundary.

Bw3--75 to 120 cm; dark yellowish brown (10YR 4/4) very gravelly loamy sand, yellowish brown (10YR 5/4) dry; single grain; loose, nonsticky, nonplastic; few very fine and fine roots; 5 percent fine gravel, 40 percent medium and coarse gravel, and 5 percent cobbles; moderately acid (pH 5.9); abrupt wavy boundary.

2C--120 to 150 cm; olive brown (2.5Y 4/3) extremely gravelly loamy sand, light olive brown (2.5Y 5/3), dry; single grain; loose, nonsticky, nonplastic; few very fine roots;10 percent fine gravel, 40 percent medium and coarse gravel, and 10 percent cobbles; moderately acid (pH 6.0).

TYPE LOCATION: North Cascades National Park, Whatcom County, Washington; 345 meters west and 430 meters south of NE corner of Section 1, T39N, R13E Willamette Meridian; Hozomeen Mountain, Washington USGS quadrangle; 48 degrees, 53 minutes, 50 seconds north latitude, 121 degrees, 2 minutes, 47 seconds west longitude; NAD83; UTM 643189 meters E, 5417873 meters N, zone 10.

RANGE IN CHARACTERISTICS:
Mean annual soil temperature: 6 to 8 degrees C. Frigid soil temperature regime.
Soil moisture control section: dry for 60 to 90 consecutive days from June to October. Xeric soil moisture regime.

A horizon:
Hue - 7.5YR or 10YR
Value - 2 or 3 moist, 3 to 5 dry
Chroma - 1 or 2 moist or dry
Fine earth texture - ashy FSL, ashy SL, or ashy COSL
Rock fragments -10 to 45 percent total
10 to 25 percent gravel
0 to 15 percent cobbles
0 to 5 percent stones
Clay content - 2 to 8 percent
Volcanic glass - 5 to 15 percent
Reaction - very strongly acid to moderately acid
Thickness - 1 to 14 centimeters

Bw horizons:
Hue -10YR or 2.5Y
Value - 3 to 5 moist, 4 to 6 dry
Chroma - 2 to 6 moist or dry
Fine earth texture - ashy COSL, ashy FSL or ashy SL in the upper part
LS or ashy LS in the lower part
Rock fragments - 25 to 80 percent total
20 to 55 percent gravel
5 to 30 percent cobbles
0 to 5 percent stones
Clay content - 2 to 8 percent
Volcanic glass - 5 to 15 percent in the upper part
0 to 10 percent in the lower part
Reaction - strongly acid to slightly acid
Thickness - 100 to 150 centimeters

2C horizons:
Hue - 2.5 Y, 10YR or variegated
Value - 3 or 4 moist, 4 to 6 moist
Chroma - 2 to 4 moist or dry
Fine earth texture -COS, LCOS or LS
Rock fragments - 35 to 80 percent total
30 to 55 percent gravel
5 to 30 percent cobbles
0 to 5 percent stones
Clay content - 0 to 5 percent
Volcanic glass - 0 to 5 percent
Reaction - strongly acid to moderately acid

COMPETING SERIES: These are the Pajo and Tripod series. The Pajo soils have a paralithic contact with weathered bedrock at a depth of 50 to 100 cm. Tripod soils have an umbric epipedon.

GEOGRAPHIC SETTING: The Lyall soils are on valley walls, terraces, alluvial fans, and debris cones at elevations of 300 to 800 meters. Slopes are 0 to 65 percent. These soils formed in alluvium and reworked glacial drift with minor amounts of volcanic ash. The climate consists of cool, dry summers and cold, wet winters. Mean annual precipitation ranges from 600 to 1700 millimeters, and mean annual air temperature ranges from 5 to 10 degrees C. Frost free season is 70 to 100 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Mesahchie (T), Goode (T), and Busterbrown (T) soils. Mesahchie soils have an umbric epipedon and a volcanic ash mantel, and form in areas of more herbaceous vegetation on valley walls and alluvial fans. Goode soils have a volcanic ash mantle and form on more stable portions of terraces, alluvial fans and valley walls. Busterbrown soils lack ash and form on wetter, more active portions of terraces, debris cones and alluvial fans.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; high to very high saturated hydraulic conductivity.

USE AND VEGETATION: Used for watershed, recreation, woodland, and wildlife habitat. Potential natural vegetation consists primarily of Douglas-fir with an understory of clasping twistedstalk, trailing blackberry, tall Oregon-grape, bracken fern, and snowberry.

DISTRIBUTION AND EXTENT: Western slopes of the North Cascade Mountains, Washington. MLRA 3. Series is of moderate extent.

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

SERIES ESTABLISHED: North Cascades National Park Service Complex soil survey, 2011.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: 0 to 18 centimeters (Oi, Oe, and upper 11 centimeters of the A horizon)
Cambic horizon: 19 to 44 centimeters (Bw1 horizon)
Vitrandic feature: 7 to 44 centimeters (A and Bw1 horizons)
Particle-size control section: 32 to 107 centimeters (25 to 100 centimeters from the mineral surface)

National Cooperative Soil Survey
U.S.A.