LOCATION CHILLIGAN AK
Established Series
Rev. MHC/JPM
02/2022
CHILLIGAN SERIES
The Chilligan series consists of very deep, well drained soils formed in a mantle of volcanic ash influenced loess overlying stratified loamy glacial outwash and lacustrine deposits. Chilligan soils are on glacial outwash plains and hillslopes. Slopes range from 0 to 35 percent. Mean annual temperature is about 35 degrees F., and the average annual precipitation is about 20 inches.
TAXONOMIC CLASS: Medial over loamy, mixed, superactive Andic Haplocryods
TYPICAL PEDON: Chilligan silt loam -- on a 3 percent slope under paper birch vegetation. (All colors are for moist soil, textures are apparent field textures)
Oi--2 inches to 0; dark reddish brown (5YR 2.5/2) fibrous forest and grass litter; abrupt smooth boundary. (1 to 3 inches thick)
E--0 to 1 inch; gray (10YR 5/1) silt loam; weak fine granular structure; very friable, nonsticky and nonplastic; many roots of all sizes; very strongly acid (pH 5.0); abrupt wavy boundary. (1 to 3 inches thick)
Bhs--1 to 3 inches; dark reddish brown (5YR 2.5/2) very fine sandy loam; moderate fine granular structure; very friable, nonsticky and nonplastic; many roots of all sizes; strongly acid (pH 5.2); abrupt wavy boundary. (0 to 3 inches thick)
Eb--3 to 5 inches; grayish brown (2.5Y 5/2) silt loam; weak fine granular structure; very friable, nonsticky and nonplastic; common very fine, fine and medium and few coarse roots; strongly acid (pH 5.2); abrupt wavy boundary. (1 to 3 inches thick)
Bsb--5 to 9 inches; reddish brown and dark reddish brown (5YR 4/4 and 5YR 3/3) very fine sandy loam; moderate fine granular structure; very friable, nonsticky and nonplastic; common very fine roots; strongly acid (pH 5.4); clear smooth boundary. (3 to 6 inches thick)
BCb--9 to 24 inches; yellowish brown and brown (10YR 5/4 and 10YR 4/3) silt loam; weak medium subangular blocky structure; very friable, nonsticky and nonplastic; few very fine roots; moderately acid (pH 5.6); abrupt smooth boundary. (6 to 16 inches thick)
2C1--24 to 41 inches; grayish brown (2.5Y 5/2) stratified fine sand, very fine sand, silt and silty clay loam; massive; friable, slightly sticky and plastic; moderately acid (pH 6.0); gradual smooth boundary. (15 to 35 inches thick)
2C2--41 to 60 inches; dark yellowish brown and dark grayish brown (10YR 3/4 and 10YR 4/2) stratified fine sand, very fine sand, silt and silty clay loam; massive; very friable, slightly sticky and slightly plastic; moderately acid (pH 6.0).
TYPE LOCATION: Matanuska-Susitna Valley Area, Alaska; about 9 miles SW of Knik; NW1/4, NE1/4 of section 21 T.14N., R.4W., Seward Meridian.
RANGE IN CHARACTERISTICS: Mean annual soil temperature ranges from 33 to 37 degrees F. The thickness of the volcanic ash influenced loess deposits ranges from 14 to 26 inches. The bulk density of the loess mantle is assumed less than 0.90 grams/cc and the phosphorous retention is assumed greater than 85 percent. The weighted average particle size of the underlying material is coarse-loamy. There are less than 15 percent coarse fragments throughout the control section. Reaction ranges from very strongly to moderately acid in the solum and moderately to slightly acid in the substratum.
The E and Eb horizons have hue moist of 10YR or 2.5Y; value moist of 4 or 5; chroma moist of 1 or 2. Texture is silt loam or very fine sandy loam.
The Bh horizon, when present, has hue moist of 2.5YR or 5YR; value moist of 2.5 or 3; chroma moist of 2 or 3. Texture is silt loam, very fine sandy loam or loam.
The Bs and Bsb horizons have hue moist of 2.5YR through 7.5YR; value moist of 3 or 4; chroma moist of 3 through 6. Texture is silt loam, very fine sandy loam or loam.
The BC horizon has hue moist of 10YR or 2.5Y; value moist of 3 through 5; chroma moist of 3 or 4.
The 2C horizons have hue moist of 10YR through 5Y; value moist of 3 through 5; chroma moist of 2 or 3. Textures are stratified and include fine sand, very fine sandy loam, silt loam, loam and silty clay loam.
COMPETING SERIES: These are the
Boulder Point,
Cohoe,
Kenai,
Kroto,
Strandline,
Suntrana, Swanson (T), Tuomi (T) and
Whitsol series in the same family. Boulder Point soils are stony throughout the lower control section. Cohoe and Suntrana soils are mottled in the control section. Kenai soils have more than 18 percent clay throughout the lower control section. Kroto and Strandline soils are not stratified. Swanson, Tuomi and Whitsol soils do not have lenses with greater than 18 percent clay in the substratum.
GEOGRAPHIC SETTING: The Chilligan series occur on glacial outwash plains and hillslopes. They formed in an admixture of eolian silt and volcanic ash overlying stratified medium and fine textured glacial outwash material. The climate is transitional maritime-continental with the average annual precipitation of about 20 inches. Mean annual temperature is about 35 degrees F.
DRAINAGE AND PERMEABILITY: Well drained. Moderate permeability in the loess mantle and moderately slow permeability in the underlying glacial material. Slow to rapid runoff.
USE AND VEGETATION: Used for wildlife habitat. Native vegetation is white spruce and paper birch.
DISTRIBUTION AND EXTENT: Southcentral Alaska. The series is of minor extent.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: WASILLA, ALASKA
SERIES ESTABLISHED: Matanuska-Susitna Soil Survey, Alaska, 1996.
REMARKS: Diagnostic horizons and features recognized in this profile are:
albic horizons from 0 to 1 and 3 to 5 inches; spodic horizons from 1 to 3 and 5 to 9 inches; assumed andic materials from 0 to 24 inches; a weighted average particle size class of coarse-loamy from 24 to 40 inches; cryic temperature regime.
National Cooperative Soil Survey
U.S.A.