LOCATION NOHOKOMEEN WA

Established Series
Rev. CAB/SBC
06/2011

NOHOKOMEEN SERIES

The Nohokomeen series consists of very deep, somewhat poorly drained soils formed in volcanic ash mixed with alluvium over glacial drift on debris aprons, terraces, debris cones and fan terraces. Slopes are 0 to 25 percent. The mean annual precipitation is about 1,800 millimeters. The mean annual temperature is about 9 degrees C.

TAXONOMIC CLASS: Coarse-loamy, isotic, frigid Aquandic Dystrudepts

TYPICAL PEDON: Nohokomeen ashy sandy loam, on a debris apron landform with a NW facing slope of 3 percent at 256 meters elevation under coniferous forest vegetation. When described on June 10, 2008 the soil was moist throughout. (Colors are for moist soil unless otherwise noted.)

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

Oe--3 to 7 cm; moderately decomposed plant material; abrupt wavy boundary.

Bw--7 to 30 cm; dark brown (7.5YR 3/4) ashy sandy loam, brown (7.5YR 5/4) dry; weak fine subangular blocky structure; very friable, soft, nonsticky, nonplastic; common very fine, fine, medium, and coarse roots throughout; 5 percent fine gravel and 5 percent medium and coarse gravel; strongly acid (pH 5.5); clear smooth boundary.

Bg1--30 to 73 cm; dark brown (7.5YR 3/4) ashy sandy loam, brown (7.5YR 5/3) dry; moderate medium subangular blocky structure; very friable, soft, nonsticky, nonplastic; common fine and medium and few very fine and coarse roots throughout; common distinct medium strong brown (7.5YR 4/6) masses of oxidized iron with clear boundaries in the matrix, and many distinct medium grayish brown (10YR 5/2) iron depletions with clear boundaries in the matrix; moderately acid (pH 5.8); abrupt smooth boundary.

Bg2--73 to 108 cm; brown (7.5YR 4/4) very fine sandy loam, brown (7.5YR 5/4) dry; moderate medium subangular blocky structure; very friable, soft, nonsticky, nonplastic; few fine roots throughout; common distinct medium grayish brown (10YR 5/2) iron depletions with diffuse boundaries in the matrix, and common distinct medium strong brown (7.5YR 4/6) masses of oxidized iron with diffuse boundaries in the matrix; moderately acid (pH 5.9); abrupt wavy boundary.

2BC--108 to 150 cm; olive brown (2.5Y 4/3) very gravelly loamy sand, light yellowish brown (2.5Y 6/3) dry; single grain; loose, nonsticky, nonplastic; few very fine roots throughout; 10 percent fine gravel, 20 percent medium and coarse gravel, and 10 percent cobbles; moderately acid (pH 6.0).

TYPE LOCATION: North Cascades National Park, Whatcom County, Washington; 560 meters west and 707 meters north of SE corner of Section 29, T34N, R12E Willamette Meridian; Mount Triumph, Washington USGS quadrangle; 48 degrees 39 minutes 43 seconds north latitude, 121 degrees 15 minutes 58 seconds west longitude; NAD83; UTM 627667 meters E, 5391320 meters N, zone 10N.

RANGE IN CHARACTERISTICS:
Mean annual soil temperature: 6 to 8 degrees C. Frigid soil temperature regime.
Soil moisture control section: dry for less than 45 consecutive days from June to October. Udic soil moisture regime.

A horizons are sometimes present with thickness ranging from 0 to 10 centimeters, textures of SL or FSL, reaction of very strongly acid or strongly acid, hue of 10YR, moist value of 2 or 3, and moist chroma of 1 or 2.

E horizons are sometimes present with thickness ranging from 0 to 3 centimeters, textures of SL or FSL, reaction of very strongly acid or strongly acid, hue of 10YR, moist value of 4 to 6, and moist chroma of 1 or 2.

Bw horizons:
Hue - 10 YR or 7.5YR
Value - 3 to 5 moist, 4 to 6 dry
Chroma - 3 or 4 moist or dry
Fine earth texture - ashy SL, ashy FSL, or ashy VFSL
Rock fragments - 0 to 30 percent total
0 to 20 percent gravel
0 to 15 percent cobbles
0 to 5 percent stones
Clay content - 3 to 8 percent
Volcanic glass - 5 to 35 percent
Reaction - strongly acid to moderately acid
Thickness - 15 to 40 centimeters

Bg horizons:
Hue -10YR or 2.5Y
Value - 3 to 5 moist, 4 to 6 dry
Chroma - 3 or 4 moist or dry
Fine earth texture - SL, FSL or SIL; ashy in the upper part in some pedons
Rock fragments - 0 to 30 percent total
0 to 25 percent gravel
0 to 10 percent cobbles
0 to 5 percent stones
Clay content - 3 to 10 percent
Volcanic glass - 0 to 15 percent
Reaction - moderately acid to slightly acid
Thickness - 40 to 80 centimeters

2BC horizon:
Hue -2.5Y or Variegated
Value - 3 to 5 moist, 4 to 6 dry
Chroma - 3 or 4 moist or dry
Fine earth texture - SL, LS or COS
Rock fragments - 35 to 85 percent total
25 to 50 percent gravel
10 to 35 percent cobbles
0 to 10 percent stones
Clay content - 0 to 6 percent
Volcanic glass - 0 to 5 percent
Reaction - moderately acid to slightly acid

COMPETING SERIES: There are no competing series in this family.

GEOGRAPHIC SETTING: The Nohokomeen soils are on debris aprons, terraces, debris cones, and fan terraces at elevations of 125 to 600 meters. Slopes are 0 to 25 percent. These soils formed in volcanic ash mixed with alluvium over glacial drift. The climate consists of cool, dry summers and cold, wet winters. Mean annual precipitation ranges from 1,700 to 2,500 millimeters, and mean annual air temperature ranges from 5 to 10 degrees C. Frost free season is 60 to 90 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Roland (T) and Tricouni (T) soils. Roland soils are on similar landforms but lack andic soil properties. Tricouni soils formed on similar terraces and debris cones but lack redoximorphic features and are well drained.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat poorly drained; moderately high to very high saturated hydraulic conductivity.

USE AND VEGETATION: Used for watershed, recreation, woodland, and wildlife habitat. Potential natural vegetation consists of western redcedar, and Douglas-fir with minor amounts of red alder and western hemlock, with an understory of vine maple, red huckleberry, sword fern, bracken fern, and salmonberry on the wetter sites.

DISTRIBUTION AND EXTENT: Western slopes of the North Cascade Mountains, Washington. MLRA 3. Series is of small 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:
Particle-size control section: 32 to 107 centimeters (25 to 100 cm from the mineral surface)
Ochric epipedon: 0 to 18 centimeters (Oi, Oe, and the upper 11 centimeters of Bw horizon)
Cambic horizon: 7 to 108 centimeters (Bw, Bg1, and Bg2 horizons)
Aquandic feature: 7 to 73 centimeters (Bw and Bg1 horizons)
Redoximorphic features with chroma of 2 or less: 30 to 108 centimeters (Bg1 and Bg2 horizons)

National Cooperative Soil Survey
U.S.A.