LOCATION CHUNILNA AK

Established Series
Rev. MHC-JPM
2/96

CHUNILNA SERIES

The Chunilna series consists of very deep, very poorly drained soils formed in a mantle of volcanic ash influenced loess over gravelly glacial till deposits. Chunilna soils are in depressions on till plains. Slopes range from 0 to 20 percent. The mean annual temperature is about 33 degrees F. and the mean annual precipitation is about 28 inches.

TAXONOMIC CLASS: Medial over loamy-skeletal, mixed Typic
Cryaquands

TYPICAL PEDON: Chunilna silt loam - on a level slope under paper birch forest at 450 feet elevation. (All colors are for moist soil, all textures are apparent field textures)

Oe--4 inches to 0; dark brown (7.5YR 4/4) partially decomposed forest litter and moss. (2 to 5 inches thick)

A1--0 to 4 inches; very dark brown (10YR 2/2) mucky silt loam with occasional lenses of yellowish brown (10YR 5/8) fine sandy loam lenses of volcanic ash; weak fine subangular blocky structure; very friable, nonsticky and nonplastic; many very fine, fine and medium roots; very strongly acid (pH 4.6); clear smooth boundary. (3 to 8 inches thick)

A2--4 to 9 inches; dark brown (10YR 3/3) silt loam with occasional lenses of yellowish brown (10YR 5/8) fine sandy loam and very fine sandy loam lenses of volcanic ash; weak fine subangular blocky structure; very friable, nonsticky and nonplastic; common very fine and fine roots; very strongly acid (pH 4.8); clear smooth boundary. (0 to 5 inches thick)

Bg--9 to 14 inches; dark brown (10YR 4/3) silt loam with common medium distinct dark grayish brown (2.5Y 4/2) mottles; weak medium subangular blocky structure; very friable, nonsticky and nonplastic; common very fine and fine roots; very strongly acid (pH 4.8); clear wavy boundary. (4 to 20 inches thick)

2Bg--14 to 22 inches; dark grayish brown (2.5Y 4/2) gravelly loam with common medium distinct strong brown (7.5YR 4/6) mottles; weak coarse subangular blocky structure; friable, slightly sticky and slightly plastic; 20 percent subangular gravel and 5 percent subangular cobble; strongly acid (pH 5.2); gradual wavy boundary. (4 to 12 inches thick)

2C1--22 to 34 inches; dark grayish brown (2.5Y 4/2) very gravelly sandy loam; massive; friable, slightly sticky and slightly plastic; 40 percent subangular gravel; moderately acid (pH 5.4); diffuse irregular boundary. (10 to 22 inches thick)

2C2--34 to 60 inches; olive gray (5Y 4/2) very gravelly sandy loam; massive; friable, slightly sticky and slightly plastic; 40 percent subangular gravel and 5 percent subangular cobble; moderately acid (pH 5.4).

TYPE LOCATION: Susitna Valley Area, Alaska; about 4 miles north of Trapper Creek; the NE 1/4 of the NE 1/4 of section 7, T. 26N., R. 5W., Seward Meridian.

RANGE IN CHARACTERISTICS: Mean annual soil temperature ranges from 33 to 37 degrees F. Depth to glacial till material ranges from 14 to 33 inches. The loess mantle is dominated by volcanic ash with moist bulk density assumed at less than 0.9 grams per cubic centimeter and phosphorous retention greater than 85 percent. The A horizons have more than 6 percent organic carbon. Reaction ranges from very strongly acid to strongly acid in the solum and strongly acid to moderately acid in the substratum.

The A horizons have moist value of 2 or 3; chroma moist of 1 thru 3. Texture is mucky silt loam or silt loam.

The Bg horizon has moist hue of 2.5Y or 10YR; value moist of 3 or 4; chroma moist of 2 or 3.

The 2Bg horizon has moist hue of 10YR or 2.5Y; value moist of 3 or 4; chroma moist of 2 or 3. Texture is sandy loam or loam. Coarse fragment content ranges from 20 to 40 percent with 10 to 40 percent subangular gravel and 0 to 10 percent subangular cobble.

The 2C horizons have moist hue of 10YR, 2.5Y or 5Y; value moist of 4 or 5; chroma moist of 1 or 2. Coarse fragment content ranges from 35 to 50 percent with 25 to 40 percent subangular gravel and 0 to 25 percent subangular cobble.

COMPETING SERIES: This is the Sukoi series in the same subgroup. Sukoi soils are medial throughout the control section and have paralithic compact till within 20 inches of the surface.

GEOGRAPHIC SETTING: Chunilna soils are in depressions on glacial till plains. Slopes range from 0 to 20 percent. Chunilna soils formed in volcanic ash influenced loess overlying very gravelly glacial till. The mean annual temperature is about 33 degrees F. and the mean annual precipitation is about 28 inches.

DRAINAGE AND PERMEABILITY: Very poorly drained. Runoff is slow. Permeability is moderate in the surface horizons and moderately slow in the underlying material.

USE AND VEGETATION: This soil is used primarily as wildlife habitat. Native vegetation is dominantly paper birch, white spruce and bluejoint reedgrass.

DISTRIBUTION AND EXTENT: Southcentral Alaska. The series is of moderated extent.

MLRA OFFICE RESPONSIBLE: Anchorage, Alaska

SERIES ESTABLISHED: Matanuska-Susitna Area, Alaska, 1996.

REMARKS: Diagnostic horizons and features recognized in this profile include: redox mottles within 9 inches of the surface; an aquic moisture regime; a cryic temperature regime; bulk density of the upper part of the control section is assumed less than 0.9 g/cc; the lower part of the control section is loamy-skeletal.

National Cooperative Soil Survey
U.S.A.

 


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04 May 2007 10:19