LOCATION SELDOVIA AK

Established Series
Rev. DVP-JDW
02/2022

SELDOVIA SERIES

The Seldovia series consists of deep and very deep, well drained soils that formed in a silty mantle of volcanic ash over variable material including glacial till, reworked glacial till, and colluvial deposits. Seldovia soils are on glacial moraines and mountainslopes. Slopes range from 8 to 65 percent. Mean annual temperature is about 37 degrees F. and the mean annual precipitation is about 70 inches.

TAXONOMIC CLASS: Medial, mixed Andic Humicryods

TYPICAL PEDON: Seldovia silt loam, on a south facing, 47 percent slope under Sitka spruce forest at 200 feet elevation. (When described, the soil was moist throughout).

Oe--2 to 0 inches; very dark brown (10YR 2/2) mucky peat; many very fine, fine, medium, and common coarse roots; extremely acid (pH 4.2); abrupt smooth boundary. (1 to 6 inches thick)

E--0 to 2 inches; dark grayish brown (10YR 4/2) silt loam; moderate fine granular structure; very friable, nonsticky, nonplastic, weakly smeary; many very fine, fine, medium, and common coarse roots; very strongly acid (pH 4.5); abrupt wavy boundary.

Bs--2 to 4 inches; dark brown (7.5YR 4/4) silt loam; moderate fine granular structure; very friable, nonsticky, nonplastic, moderately smeary; many very fine, fine, medium, and common coarse roots; very strongly acid (pH 4.5); abrupt wavy boundary.

Eb--4 to 5 inches; dark grayish brown (10YR 4/2) silt loam; moderate fine granular structure; very friable, nonsticky, nonplastic, weakly smeary; many very fine, fine, medium, and common coarse roots; 2 percent gravel; very strongly acid (pH 5.0); abrupt wavy boundary.(combined thickness of E horizons is 4 to 11 inches)

Bsb1--5 to 9 inches; dark reddish brown (5YR 3/4) silt loam; moderate fine granular structure; very friable, nonsticky, nonplastic, moderately smeary; many very fine, fine, medium, and common coarse roots; 2 percent gravel; strongly acid (pH 5.5); clear wavy boundary.

Bhsb1--9 to 19 inches; dark reddish brown (5YR 3/2) silt loam; moderate fine granular structure; very friable, nonsticky, nonplastic, moderately smeary; common very fine, fine, and medium roots; strongly acid (pH 5.5); clear wavy boundary.

Bhsb2--19 to 29 inches; dark reddish brown (5YR 3/3) silt loam; moderate fine granular structure; very friable, slightly sticky, slightly plastic, moderately smeary; few fine and fine roots; 2 percent gravel; medium acid (pH 5.8); clear wavy boundary.

2Bsb--29 to 46 inches; dark reddish brown (5YR 3/4) very gravelly silt loam; weak medium subangular blocky; very friable, nonsticky, nonplastic, moderately smeary; 30 percent gravel and 10 percent cobble; medium acid (pH 5.8). (combined thickness of B horizons is 34 to 45 inches)

2C--46 to 60 inches; light olive brown (2.5Y 5/4) and grayish brown (2.5Y 5/2) very gravelly loam; massive; friable, nonsticky, nonplastic; 45 percent gravel and 15 percent cobble; medium acid (pH 5.8).

TYPE LOCATION: Kenai Peninsula Area, Alaska; about 5 miles south of Nanwalek, 1360 feet south and 100 feet east of the NW corner of section 27, T. 10S., R. 16W., Seward Meridian; USGS Seldovia B-6 quadrangle; lat. 59 degrees 17 minutes 10 seconds N. and long. 151 degrees 55 minutes 36 seconds W.

RANGE IN CHARACTERISTICS: The mean annual soil temperature is 36 to 40 degrees F. Thickness of the ashy mantle ranges from 21 to 32 inches. Thickness of the solum is 40 to 50 inches. Depth to bedrock ranges from 40 to greater than 60 inches. The pH of the mineral horizons ranges from 4.5 to 5.8.

The E and Eb horizons have hue of 2.5Y or 10YR, value of 4 to 6, and chroma of 2 or 3. They are silt loam or very fine sandy loam. They are weakly smeary throughout.

The Bs and Bsb horizons have hue of 7.5YR or 5YR, value of 3 or 4, and chroma of 3 or 4. They are silt loam or very fine sandy loam with 0 to 14 percent gravel. They are moderately smeary throughout. Organic carbon content is assumed to be 5 to 12 percent.

The Bhs and Bhsb horizons have hue of 2.5YR or 5YR, value of 2.5 or 3, and chroma of 1 to 3. They are silt loam or very fine sandy loam. Gravel and cobble content is 0 to 14 percent. They are moderately smeary throughout. Organic carbon is assumed to be 12 to 16 percent.

The 2Bsb horizon has hue of 7.5YR or 5YR value of 3 or 4, and chroma of 3 or 4. Texture of the fines is silt loam or very fine sandy loam. Rock fragments range from 15 to 45 percent and include 10 to 30 percent gravel and 0 to 15 percent cobble. They are moderately smeary throughout. Organic carbon content is assumed to be 5 to 12 percent.

The 2C horizon has hue of 2.5Y or 10YR, value of 4 to 6, and chroma of 2 to 4. Texture of the fines is loam or sandy loam. Rock fragments range from 35 to 60 percent and include 25 to 45 percent gravel and 10 to 20 percent cobble.

COMPETING SERIES: Soils in the same family include the Portgraham series. Portgraham soil are less than 40 inches to bedrock. Soils in the same subgroup include the Kasitsna, Nanwalek, and Portgraham series. Kasitsna soils have a particle size control section that is composed of medial over loamy skeletal material. Nanwalek soils have a particle size control section that has more than 35 percent rock fragments. Portgraham soils are moderately deep to bedrock.

GEOGRAPHIC SETTING: Seldovia soils are formed in an ash mantle that averages 25 inches thick over variable materials including glacial till and colluvial deposits. Volcanic ash has been incorporated into the underlying till and colluvium to depths of 40 inches or more by leaching and mass movement. Seldovia soils are on glacial moraines and mountainslopes. Slopes range from 8 to 120 percent. Elevations are 20 to 1500 feet.

The climate is maritime with mild winters and cool summers. Mean annual precipitation ranges from 65 to 75 inches and the mean annual snowfall is 70 to 140 inches. Mean January temperature is 23 degrees F., mean July temperature is 52 degrees F., and the mean annual temperature ranges from 35 to 39 degrees F.

GEOGRAPHICALLY ASSOCIATED SOILS: These include the Jakolof, Koyuktolik, Kasitsna, Portgraham, and Tutka soils. Jakolof soils have a control section formed in sand and gravel of stream terraces. Koyuktolik soils are formed in organic matter accumulated in depressions. Portgraham and Kasitsna soils occur on similar landscapes or in complex with Seldovia soils. Tutka soils have bedrock within 20 inches and occur on glacially abraded bedrock ridges.

DRAINAGE AND PERMEABILITY: Well drained. Runoff is slow to rapid. Permeability is moderate in the ash mantle and moderately slow in the glacial till and colluvium.

USE AND VEGETATION: These soils are used for timber production, subsistence, recreation, and wildlife habitat. Seldovia soils have native vegetation of Sitka spruce, devils club, alder, salmonberry, fern, and bluejoint grass.

DISTRIBUTION AND EXTENT: Kenai Peninsula, Alaska. The series is of moderate extent.

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

SERIES ESTABLISHED: Lower Kenai Peninsula Area, Alaska, 1998.

REMARKS: Diagnostic horizons and features recognized in this profile include:

Albic horizons 0 to 2 and 4 to 5 inches (E, and Eb2).
Spodic horizons 2 to 4, 5 to 9, 9 to 19, 19 to 29, and 29 to 46 inches (Bs, Bsb1, Bhsb1, Bhsb2, and 2Bsb2).
Andic soil properties from 0 to 46 inches.
6 percent or more organic carbon in the Bhsb horizons 9 to 29 inches.
Cryic temperature regime.

National Cooperative Soil Survey
U.S.A.