LOCATION ILIAMNA                 AK

Tentative Series
Rev. DVP/DLM
02/2022

ILIAMNA SERIES

Depth class: very deep
Drainage class: well drained
Parent material: ash influenced loess over glaciofluvial deposits
Landform: outwash plains, nunataks
Slopes: 0 to 45 percent
Mean annual precipitation: 25 to 35 inches
Mean annual temperature: 33 to 36 degrees F.

TAXONOMIC CLASS: Medial over sandy or sandy-skeletal, amorphic over mixed Andic Humicryods

TYPICAL PEDON: Iliamna silt loam - on a slope of 28 percent percent under tall grass and shrub vegetation at 617 feet elevation. (All colors are for moist soil unless noted)

Oe--0 to 2 inches; very dark brown (10YR 2/2) moderately decomposed plant material; common very fine, fine, medium, and coarse roots; extremely acid (pH 4.4); clear smooth boundary. (1 to 4 inches thick)

E--2 to 3 inches; dark grayish brown (10YR 4/2) silt loam; weak fine granular structure; very friable, nonsticky and nonplastic; many very fine, fine, medium, and coarse roots; very strongly acid (pH 4.7); clear wavy boundary. (1 to 3 inches thick)

Bhs--3 to 7 inches; very dusky red (2.5YR 2.5/2) mucky silt loam; moderately fine granular structure; very friable, nonsticky and nonplastic; many very fine, fine, medium, and coarse roots; smeary; very strongly acid (pH 5.0); clear wavy boundary. (4 to 6 inches thick)

Eb--7 to 8 inches; dark grayish brown (10YR 4/2) silt loam; weak fine granular structure; very friable, nonsticky and nonplastic; many very fine, fine, medium, and coarse roots; strongly acid (pH 5.3); clear wavy boundary. (1 to 3 inches thick)

Bhsb--8 to 12 inches; dark reddish brown (5YR 3/3) mucky silt loam; moderate fine granular structure; very friable, nonsticky and nonplastic; many very fine, fine, medium, and common coarse roots; smeary; strongly acid (pH 5.3); clear wavy boundary. (3 to 9 inches thick)

Bsb--12 to 14 inches; dark reddish brown (5YR 3/4) silt loam; moderately fine granular structure; very friable, nonsticky and nonplastic; common very fine, fine roots, few medium and coarse roots; smeary; moderately acid (pH 5.7); clear wavy boundary. (1 to 4 inches thick)

Bw--14 to 19 inches; dark yellowish brown (10YR 3/4) silt loam; moderate fine granular structure; friable, nonsticky and nonplastic; common very fine and fine roots; smeary; moderately acid (pH 5.8); clear wavy boundary. (4 to 9 inches thick)

BC--19 to 29 inches; olive brown (2.5Y 4/4) silt loam; moderate fine granular structure; firm slightly sticky and slightly plastic; few very fine and fine roots; moderately acid (pH 5.8); clear wavy boundary. (0 to 6 inches thick)

2C--29 to 60 inches; dark grayish brown (2.5Y 4/2) loamy fine sand; single grain; loose, nonsticky and nonplastic; moderately acid (pH 5.8).

TYPE LOCATION: Western Kenai Area, Alaska; about 9 miles south of Clam Gulch; 750 feet east and 2,300 feet south of the NE 1/4 of section 10, T. 1 S., R. 12 W; Kenai A-4 SW 1:25,00 quad; Steward Meridian; UTM north 6664150 and UTM east 592759, zone 5.

RANGE IN CHARACTERISTICS:

Soil moisture regime: udic
Mean annual soil temperature: 34 degrees F
Thickness of ash influenced loess: 18 to 25 inches
Thickness of silty solum: 18 to 35 inches
Depth to sands and gravel: 18 to 35 inches

O horizon:
Matrix color: hue of 7.5YR to 10YR; value of 2 to 4; chroma of 2 to 4
Reaction class: extremely acid to strongly acid

E or Eb horizons:
Matrix color: hue of 10YR to 2.5Y; value of 4 or 5; chroma of 1 to 3
Texture: silt loam, very fine sandy loam
Reaction class: extremely acid or strongly acid

Bhs or Bhsb horizons:
Matrix color: hue of 2.5YR or 5YR; value of 2 or 3; chroma of 2 or 3
Texture: mucky silt loam, mucky very fine sandy loam
Total organic carbon: 6 to 12 percent
Reaction class: very strongly acid or strongly acid

Bs horizon:
Matrix color: hue of 5YR or 7.5YR; value of 3 or 5; chroma of 3 or 4
Texture: silt loam, very fine sandy loam
Reaction class: very strongly or strongly acid

Bw horizon:
Matrix color: hue of 7.5YR or 10YR; value of 3 or 4; chroma of 3 or 4
Texture: silt loam, very fine sandy loam, fine sandy loam
Reaction class: strongly acid or moderately acid

BC horizon:
Matrix color: hue of 10YR or 2.5Y; value of 3 or 4; chroma of 3 or 4
Texture: silt loam, very fine sandy loam, fine sandy loam
Coarse fragments: 0 to 5 percent gravel

2C horizon:
Matrix color: hue of 2.5Y or 5Y; value of 4 or 5; chroma of 2 or 3
Texture: sand, loamy fine sand modified by 0 to 45 percent total coarse fragments; 0 to 45 percent gravel, 0 to 10 percent cobbles
Reaction class: moderately acid or slightly acid

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

GEOGRAPHIC SETTING:
Depth class: very deep
Drainage class: well drained
Parent material: ash influenced loess over glaciofluvial deposits
Landform: outwash plains, nunataks
Slopes: 0 to 45 percent
Mean annual temperature: 33 to 36 degrees F.
Mean annual precipitation: 25 to 35 inches

GEOGRAPHICALLY ASSOCIATED SOILS: These include Whitsol and Tuxendi soils. Whitsol soil have less than 6 percent total carbon in the spodic horizon and occur on similar landforms. Tuxendi soils are somewhat poorly drained and occur on discharge slopes.

DRAINAGE AND PERMEABILITY: Well drained, low to high runoff, saturated hydraulic conductivity is high in the solum and moderately high to high in the substratum.

USE AND VEGETATION: Used for Wildlife habitat and recreation. The native vegetation is Lutz spruce, paper birch, alder, grasses, and shrubs.

DISTRIBUTION AND EXTENT: MLRA 224 Cook Inlet Lowlands, South-Central Alaska, The series is of small extent.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: WASILLA, ALASKA

SERIES PROPOSED: Area, Alaska, 1998

REMARKS: Diagnostic features and horizons recognized in this profile include:
Albic horizon: 2 to 3 and 7 to 8 inches.
Spodic horizon with greater than 6 percent total carbon: from 3 to 7 and 8 to 12 inches.
Temperature regime: cryic

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National Cooperative Soil Survey
U.S.A.