LOCATION SUNTRANA AK
Established Series
Rev. KMO-JPM
02/2022
SUNTRANA SERIES
The Suntrana series consists of very deep, poorly drained soils formed in a mantle of ash-influenced loess overlying dense glaciofluvial material on glacial moraines. Slopes range from 2 to 7 percent. The mean annual temperature is about 34 degrees F., and the average annual precipitation is about 25 inches.
TAXONOMIC CLASS: Medial over loamy, mixed, superactive Andic Cryaquods
TYPICAL PEDON: Suntrana silt loam -- on a 2 percent slope under forest vegetation. (All colors are for moist soil)
Oe--4 inches to 0; very dark brown (10YR 2/2) moderately decomposed forest litter and moss; abrupt smooth boundary. (2 to 6 inches thick)
E--0 to 1 inch; dark grayish brown (10YR 4/2) silt loam; weak fine subangular blocky structure; friable; many fine roots; strongly acid; abrupt smooth boundary. (0 to 3 inches thick)
Bs1-- 1 to 3 inches; very dark gray (10YR 3/1) silt loam; weak fine subangular blocky structure; friable; many fine roots; strongly acid; abrupt smooth boundary. (1 to 2 inches thick)
Bs2--3 to 5 inches; dark brown (7.5YR 3/2) silt loam; weak fine subangular blocky structure; friable; common fine roots; strongly acid; abrupt smooth boundary. (0 to 4 inches thick)
C1--5 to 10 inches; grayish brown (10YR 5/2) very fine sandy loam; common medium prominent yellowish red (5YR 4/6) mottles; massive; friable; strongly acid; abrupt smooth boundary. (0 to 10 inches thick)
C2--10 to 20 inches; pale brown (10YR 6/3) silt loam; few fine faint brown (10YR 5/3) mottles; massive; friable; moderately acid; abrupt smooth boundary. (0 to 10 inches)
2C3--20 to 60 inches; brown (10YR 5/3) silty clay loam; common fine faint dark yellowish brown (10YR 4/4) mottles; massive; very firm; moderately acid.
TYPE LOCATION: Yentna Area, Alaska; NE 1/4, SE 1/4, Section 11, T. 14N., R. 9W, Seward Meridian.
RANGE IN CHARACTERISTICS: Thickness of the solum ranges from 5 to 15 inches. Texture of the upper part of the control section is silt loam, loam, or fine sandy loam with the exchange complex dominated by amorphous material. Texture of the lower part of the control section is dominantly silty clay loam. Depth to the contrasting firm glaciofluvial material ranges from 14 to 20 inches. Mottles are present below the spodic horizons. Reaction throughout the profile ranges from very strongly acid to moderately acid.
An A horizon is present in some pedons, with thickness ranging from 0 to 4 inches. Hue is 7.5YR or 10YR, value moist is 2 or 3, and chroma moist is 1 or 2. Texture is dominantly silt loam, but ranges to include loam or fine sandy loam.
The E horizon has value moist from 2 to 6, and chroma moist of 1 or 2. Texture is dominantly silt loam, but ranges to include loam or fine sandy loam.
The Bs horizons have hue from 5YR to 10YR, value moist from 3 to 5, and chroma moist from 2 to 4. Texture is dominantly silt loam, but ranges to include loam or fine sandy loam.
A BC horizon is present in some pedons. Thickness ranges from 0 to 6 inches. Hue is 7.5YR or 10YR, value moist ranges from 3 to 6, and chroma moist from 2 to 4. Texture is silt loam or loam.
The C horizon has hue of 10YR or 2.5Y, value moist from 4 to 6, and chroma moist from 2 to 4. Texture is silt loam or very fine sandy loam.
The 2C horizon has hue of 10YR or 2.5Y, value moist from 4 to 6, and chroma moist of 2 or 3. Texture is silty clay loam with lenses of silty clay. Consistence is firm or very firm.
COMPETING SERIES: These are the
Boulder Point,
Cohoe,
Darling,
Kenai,
Kroto(T),
Strandline(T), Swanson(T), Tuomi(T) and
Whitsol series. All these series are do not have mottles in the upper 20 inches of the profile. Also, Boulder Point soils have a stony substratum and Cohoe soils have a stratified sandy and silty substratum within the control section.
GEOGRAPHIC SETTING: Suntrana soils formed in an ash-influenced loess mantle overlying firm glaciofluvial material on moraines. Slopes range from 2 to 7 percent.
The climate is transitional from maritime to continental with long cold winters and short warm summers. Annual average precipitation ranges from 20 to 30 inches. Mean annual temperature ranges from 30 to 40 degrees F.
DRAINAGE AND PERMEABILITY: Poorly drained. Slow to medium runoff. Moderate permeability in the loess mantle and very slow in the firm substratum.
USE AND VEGETATION: The native vegetation is a forest of white and black spruce, paper birch and alder. A few areas support sparse forest with an understory of bluejoint grass.
DISTRIBUTION AND EXTENT: Southcentral Alaska. The series is of minor extent.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: WASILLA, ALASKA
SERIES ESTABLISHED: Yentna Area, Alaska. 1986.
REMARKS: Diagnostic horizons and features recognized in this pedon include: spodic horizons from 1 to 5 inches; cryic temperature regime; exchange complex dominated by amorphous material from 10 to 20 inches; loamy particle size below 20 inches; redox features occur within 50 centimeters of the mineral surface and directly below the spodic horizon.
National Cooperative Soil Survey
U.S.A.