LOCATION EWAN                    AK

Established Series
Rev. MHC/JPMLEE
02/2022

EWAN SERIES

The Ewan series consists of very deep, very poorly or poorly drained soils formed in an admixture of loamy lacustrine and alluvial deposits. Ewan soils are in drainage depressions on lacustrine terraces. Slopes range from 2 to 8 percent. The mean annual temperature is about 26 degrees F. and the mean annual precipitation is about 16 inches.

TAXONOMIC CLASS: Fine-loamy, mixed, superactive, nonacid Typic Cryaquepts

TYPICAL PEDON: Ewan silt loam - on a 4 percent slope under low willow shrub at 2600 feet elevation. (All colors are for moist soil)

Oi--1 inch to 0 inches; dark yellowish brown (10YR 3/4) peat; many very fine, fine and medium, and few coarse roots; gradual smooth boundary. (1 to 6 inches thick)

Ag--0 to 4 inches; very dark gray (10YR 3/1) silt loam; weak medium subangular blocky structure; very friable, slightly sticky and slightly plastic; reduced matrix; many very fine, fine and medium roots; moderately acid (pH 5.8); gradual wavy boundary. (2 to 6 inches thick)

Cg1--4 to 22 inches; dark gray (5Y 4/1) loam; weak coarse subangular blocky structure; very friable, slightly sticky and slightly plastic; common large distinct dark greenish gray (5GY 4/1) redox depletions; 5 percent subangular and rounded gravel; common very fine and fine roots; moderately acid (pH 5.8); gradual wavy boundary. (14 to 26 inches thick)

Cg2--22 to 49 inches; dark gray (5Y 4/1) loam; massive; friable; sticky and plastic; many large distinct dark greenish gray (5GY 4/1) redox depletions; 5 percent subangular and rounded gravel; neutral (pH 6.8). (0 to 26 inches thick)

Cg3--49 to 60 inches; dark greenish gray (5GY 4/1 and 5G 4/1) gravelly sandy clay loam; massive; friable; sticky and plastic; reduced matrix; 15 percent subangular and rounded gravel; neutral (pH 6.8).

TYPE LOCATION: Gulkana River Area, Alaska; about 21 miles (34 kilometers) north of Sourdough; the NE1/4 of the NW1/4 of section 8, T.12N., R.2W., Copper River Meridian.

RANGE IN CHARACTERISTICS: The control section is fine-loamy. Typically, reduced matrix colors and/or redox depletions occur within 20 inches of the surface. Reaction is moderately acid to neutral.

The Ag and ACg horizons have hue of 10YR, 2.5Y, 5Y, or 5GY; value moist of 3 or 4; chroma moist of 0, 1, or 2. Texture is loam, silt loam, or silty clay loam. Rock fragments range from 0 to 20 percent and include 0 to 15 percent subangular and rounded gravel; 0 to 10 percent subangular and rounded cobble.

The Cg horizons have hue of 10YR, or 2.5Y, 5Y or 5GY; value moist of 2, 3 or 4; chroma moist of 0, 1, 2, or 3. Texture is silt loam, loam, silty clay loam or sandy clay loam with strata of fine sand and sand common. Rock fragments range from 0 to 20 percent and include 0 to 15 percent subangular and rounded gravel and 0 to 10 percent subangular and rounded cobble. These horizons have a reduced matrix and/or common or many redox features; when present, redox concentrations have hue of 5YR, 7.5YR or 10YR; chroma moist of 4 through 6; redox depletions have hue of 2.5Y, 5Y, 5G, or 5GY; chroma moist of 0 through 2.

The C horizon (when present) has hue of 10YR, 2.5Y, or 5Y; value moist of 3 through 5; chroma moist of 1 or 2. Texture is silt loam, loam, silty clay loam, or sandy clay loam with strata of fine sand and sand common. Rock fragments range from 0 to 20 percent and include 0 to 15 percent subangular and rounded gravel and 0 to 10 percent subangular or rounded cobble

COMPETING SERIES: These are the Kalafonsky and Karluk in the same subgroup. Kalafonsky soils have a contrasting coarse silty over sandy or sandy-skeletal particle-size class. Karluk soils have less than 15 percent fine sand or coarser in the control section.

GEOGRAPHIC SETTING: Ewan soils are in depressions along drainages on lacustrine terraces. Slopes range from 2 to 8 percent. Ewan soils formed in an admixture of loamy lacustrine and alluvial deposits. The mean annual temperature is about 26 degrees F. and the mean annual precipitation is about 16 inches.

DRAINAGE AND PERMEABILITY: Very poorly or poorly drained. Runoff is slow. Permeability is moderate.

USE AND VEGETATION: This soil is used primarily as wildlife habitat. Native vegetation is dominantly open black spruce forest with an understory of low willow shrub.

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

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

SERIES ESTABLISHED: Gulkana River Area, Alaska, 1999

REMARKS: Diagnostic horizons and features recognized in this profile include: a reduced matrix from 0 to 60 inches; aquic conditions; a cryic temperature regime; pH values greater than 5.5 (1:1 H2O) throughout the profile; a control section from 10 to 40 inches that is fine-loamy.

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National Cooperative Soil Survey
U.S.A.