LOCATION NIKISHKA                AK

Established Series
Rev. DVP-JPM
05/2022

NIKISHKA SERIES

The Nikishka series consists of very deep, well drained soils that formed in a thin layer of ash-influenced loess overlying glaciofluvial deposits. Nikishka soils are on outwash plains, stream escarpments, and moraines. Slopes range from 0 to 45 percent. Mean annual temperature is about 38 degrees F., and the average annual precipitation is about 19 inches.

TAXONOMIC CLASS: Sandy-skeletal, mixed Typic Haplocryods

TYPICAL PEDON: Nikishka silt loam - under forest vegetation (All colors are for moist soil)

Oi--3 1/2 to 3 inches; forest litter. (0 to 2 inches thick)

Oe--3 inches to 0; dark reddish brown (5YR 2/2) mat of roots and decaying organic materials; many white and yellow mycelia; many white sand size grains of volcanic ash, especially at bottom of horizon; very strongly acid; abrupt smooth boundary. (2 to 3 inches thick)

E--0 to 2 inches; dark gray (5Y 4/1) and gray (5Y 5/1) silt loam; weak fine subangular blocky structure; very friable; common roots; very strongly acid; abrupt irregular boundary. (0 to 3 inches thick)

Bs1--2 to 4 inches; dark reddish brown (5YR 3/3) silt loam; weak fine and medium subangular blocky structure; very friable; common roots; strongly acid; abrupt irregular boundary. (1 to 5 inches thick)

Bs2--4 to 8 inches; strong brown (7.5YR 5/6) and brown (10YR 4/3) silt loam; weak medium and coarse subangular blocky structure; very friable; common roots; medium acid; clear wavy boundary. (3 to 5 inches thick)

BC--8 to 13 inches; dark yellowish brown (10YR 4/4) silt loam; weak coarse subangular blocky structure; very friable; few roots; slightly acid; clear wavy boundary. (3 to 10 inches thick)

2C1--13 to 21 inches; olive brown (2.5Y 4/4) gravelly silt loam; massive; very friable; few roots; 20 percent gravel; slightly acid; abrupt wavy boundary. (0 to 12 inches thick)

3C2--21 to 60 inches; variegated sand and gravel; loose; few roots decreasing with depth; medium acid.

TYPE LOCATION: Kenai-Kasilof Area, Alaska. NW1/4, SW1/4, Section 15, T.7N., R.12W., Seward Meridian.

RANGE IN CHARACTERISTICS: Thickness of the loess mantle over the coarse substratum ranges from 8 to 14 inches. The solum thickness ranges from 8 to 13 inches. There is less than 15 percent gravel in the loess mantle. The lower part of the control section has 50 to 70 percent coarse fragments with 10 to 15 percent cobbles, and 40 to 55 percent gravel. The weighted average coarse fragment content of the control section is greater than 35 percent. Reaction throughout the profile ranges from slightly to extremely acid.

The E horizon is absent in some profiles.

The Bs horizons have hue ranging from 2.5YR to 10YR; value moist from 3 to 5; and chroma moist from 2 to 6.

COMPETING SERIES: These are the Lutak and Yakutat(T) series in the same family and the Bernice series. Bernice soils have solums less than 7 inches thick. Lutak soils have massive firm substratums. Yakutat(T) soils have loamy sand or coarser texture with greater than 35 percent coarse fragments in the solum.

GEOGRAPHIC SETTING: The Nikishka soils occur on very gravelly moraines, stream escarpments, and outwash plains. The soils formed in a thin layer of eolian silt loam and volcanic ash overlying coarse textured glaciofluvial material. The climate is maritime transitional. Mean annual air temperatures range from 33 to 43 degrees F., and the mean annual precipitation ranges from 16 to 22 inches. Slopes range from 0 to 45 percent.

GEOGRAPHICALLY ASSOCIATED SOILS: These include the competing Bernice series and the Kalifonsky, Naptowne, Salamatof, and Soldatna series. Kalifonsky soils occur in depressions and are poorly drained. Naptowne soils occur on similar landforms and are non-skeletal. Soldotna soils occur on similar landforms and have loess mantles thicker than 15 inches. Salamatof soils occur in muskegs and are organic soils.

DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderate in the loess mantle and rapid in the substratum. Runoff is slow to rapid.

USE AND VEGETATION: The native vegetation is a forest of white spruce, paper birch, and quaking aspen. Some areas are cleared, primarily for small gardens.

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

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

SERIES ESTABLISHED: Kenai-Kasilof Area, Alaska, 1960.

REMARKS: Diagnostic horizons and features recognized in this soil are: a.spodic horizon from 2 to 8 inches; cryic temperature regime; a transition zone 8 inches thick between coarse-silty material and sandy-skeletal material; weighted average of sandy-skeletal particle size from 10 to 40 inches.

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National Cooperative Soil Survey
U.S.A.