LOCATION SWEDNA AK
Established Series
Rev. MHC-JPM
02/2022
SWEDNA SERIES
The Swedna series consists of very deep, very poorly or poorly drained soils that formed in stratified alluvium over gravelly alluvium. Swedna soils are on floodplains. Slopes range from 0 to 8 percent. The mean annual temperature is about 26 degrees F., and the average annual precipitation is about 16 inches.
TAXONOMIC CLASS: Coarse-loamy over sandy or sandy-skeletal, mixed, superactive, nonacid Typic Cryaquents
TYPICAL PEDON: Swedna fine sandy loam - on a 2 percent convex slope with a westerly exposure under sedge and bluejoint reedgrass at 2475 feet elevation. (All colors are for moist soil)
Oi/C--1 inch to 0; dark reddish brown (5YR 3/3) peat with lenses of very dark grayish brown (10YR 3/2) fine sandy loam; many very fine, fine and medium roots; moderately acid (pH 5.6); abrupt smooth boundary. (0 to 2 inches thick)
AC--0 to 1 inch; very dark grayish brown (10YR 3/2) fine sandy loam; weak thick platy structure; very friable, nonsticky and nonplastic; many very fine, fine and medium roots; moderately acid (pH 5.6); clear smooth boundary. (0 to 4 inches thick)
C--1 to 8 inches; dark grayish brown (10YR 4/2) stratified fine sand through silt with composite texture of fine sandy loam; weak medium subangular blocky structure; very friable, nonsticky and nonplastic; common very fine and fine roots; moderately acid (pH 5.6); clear smooth boundary. (0 to 8 inches thick)
Cg1--8 to 27 inches; very dark grayish brown (10YR 3/2) stratified fine sand through silt with composite texture of fine sandy loam; weak medium subangular blocky structure; very friable, nonsticky and nonplastic; many medium prominent yellowish red (5YR 4/6) redox concentrations and dark greenish gray (5GY 4/1) redox depletions; common very fine and fine roots; moderately acid (pH 5.8); gradual wavy boundary. (6 to 16 inches thick)
Cg2--27 to 31 inches; dark greenish gray (5GY 4/1) stratified sand through silt with a composite texture of sandy loam; weak medium subangular blocky structure; very friable, nonsticky and nonplastic; reduced matrix with many medium prominent dark reddish brown (2.5YR 3/4) redox concentrations; common very fine and fine roots; moderately acid (pH 6.0); clear smooth boundary. (0 to 12 inches thick)
2C4--31 to 60 inches; dark brown (10YR 3/3) very gravelly coarse sand; single grain; loose, nonsticky and nonplastic; 40 percent rounded gravel and 10 percent rounded cobble; slightly acid (pH 6.4).
TYPE LOCATION: Gulkana River Area, Alaska; about 19 miles (30 kilometers) north of Sourdough; the NW1/4 of the NW1/4 of section 29, T.12N., R.2W., Copper River Meridian.
RANGE IN CHARACTERISTICS: These soils are stratified sand through silt. The upper sediments range from 10 to 37 inches in thickness over very and extremely gravelly sand. The upper part of the control section is coarse-loamy upon mixing. Organic carbon content is assumed to vary irregularly with increasing depth. Depth to a reduced matrix or many redox features ranges from 0 to 10 inches. Reaction throughout the profile ranges from moderately acid to neutral.
The AC horizon has hue of 10YR or 2.5Y; value moist of 2 through 4; chroma moist of 1 through 3. Texture is commonly fine sandy loam but ranges to include sandy loam, or fine sand.
The C horizon (when present) has hue of 10YR or 2.5Y; value moist of 3 or 4; chroma moist of 1 through 3. Texture is stratified sand through silt; occasional pockets and strata of organic materials occur and have texture of muck or mucky peat.
The Cg horizon has hue of 10YR through 5BG; value moist of 2.5 through 4; chroma moist of 1 or 2. Texture is stratified sand through silt. These horizons have a reduced matrix and/or common or many redox features; when present, redox concentrations have hue of 5YR through 10YR; chroma moist of 4 through 6; redox depletions have hue of 2.5Y through 5GY; chroma moist of 1 or 2.
The 2C horizons are variegated sand and gravel. Texture includes sand or coarse sand. Rock fragments range from 35 to 70 percent and include 25 to 60 percent rounded gravel and 0 to 30 percent rounded cobble. Pockets and strata of sand and silt are common.
COMPETING SERIES: These are the
Niklavar soils in the same family. Niklavar soils lack redoximorphic features in the upper 10 inches.
GEOGRAPHIC SETTING: The Swedna soils are on floodplains. Slopes range from 0 to 8 percent. Swedna soils formed in stratified loamy alluvium 10 to 37 inches thick, underlain by very gravelly sand. The mean annual temperature is about 26 degrees F. and the average annual precipitation is about 16 inches. Elevation ranges from 1850 to 2475 feet.
DRAINAGE AND PERMEABILITY: Very poorly or poorly drained. Slow to medium runoff. Moderate permeability in the upper horizons and rapid in the gravelly underlying material. Swedna soils are subject to flooding.
USE AND VEGETATION: Mostly sedges, bluejoint reedgrass and low willow. Primary uses of these soils are for recreation and wildlife habitat.
DISTRIBUTION AND EXTENT: Gulkana River Area, Alaska. The soil is of minor extent.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: WASILLA, ALASKA
SERIES ESTABLISHED: Gulkana River Area, Alaska. 1999
REMARKS: Diagnostic features recognized in this profile include: no diagnostic horizons; redox depletions and reduced matrix from 8 to 31 inches; assumed irregular decrease in organic carbon based on colors, stratification, and frequent flooding; cryic temperature regime; coarse loamy particle size (weighted average) from 0 to 31 inches and sandy skeletal particle size from 31 to 60 inches.
National Cooperative Soil Survey
U.S.A.