LOCATION NAPTOWNE AK

Established Series
Rev. SR-JPM
8/95

NAPTOWNE SERIES

The Naptowne series consists of very deep, well drained soils that formed in a mantle of eolian silt loam and volcanic ash overlying glacial till. Naptowne soils are on moraines and lower mountain sideslopes. Slopes range from 0 to 45 percent. Mean annual temperature is about 34 degrees F., and the average annual precipitation is about 22 inches.

TAXONOMIC CLASS: Medial over loamy, mixed Typic Haplocryods

TYPICAL PEDON: Naptowne silt loam - on a 10 percent slope under forest vegetation. (All colors are for moist soil)

Oi--2 to 1 1/2 inches; forest litter.

Oe--1 1/2 inches to 0; dark reddish brown (R 2/2) mat of roots, moss, and decomposing parts of plants; mycelia; layers of white grains the size of sand at the bottom of horizon; medium acid; abrupt smooth boundary. (1 to 4 inches thick)

E--0 to 1 1/2 inches; gray (10YR 5/1) silt loam; weak fine subangular blocky structure; friable; common medium distinct brown patches; abundant roots; charcoal particles; very strongly acid; abrupt wavy boundary. (1 to 2 inches thick)

Bs--1 1/2 to 5 inches; brown (7.5YR 4/4) and dark yellowish brown (10YR 4/4) silt loam; weak fine subangular blocky structure; friable, roots plentiful; strongly acid; clear wavy boundary. (2 to 6 inches thick)

BC--5 to 9 inches; olive brown (2.5Y 4/4) silt loam; weak medium subangular blocky structure; friable; few roots; streaks and patches of brown; vesicular; few rounded pebbles; medium acid; clear wavy boundary. (0 to 6 inches thick)

C1--9 to 19 inches; olive (5Y 4/3) silt loam; weak thick platy structure; very friable; few roots; rounded pebbles up to 2 inches in diameter; medium acid; abrupt wavy boundary. (6 to 20 inches thick)

2C2--19 to 60 inches; olive (5Y 4/3) gravelly sandy loam; massive breaking to weak fine angular blocks; firm in place, friable broken out; common medium distinct patches of yellowish brown; few roots; contains several boulders; medium acid.

TYPE LOCATION: Kenai - Kasilof Area, Alaska. SE 1/4 of the NE 1/4 of ection 13, T.5N., R.8W., Seward Meridian.

RANGE IN CHARACTERISTICS: The solum ranges from 3 to 7 inches in thickness. Depth to gravelly till ranges from 15 to 30 inches. Texture of the control section is silt loam or sandy loam with less than 18 percent clay and more than 15 percent fine sand or coarser. The exchange complex of that part of the control section above the glacial till is dominated by amorphous material. Reaction throughout the profile is strongly or moderately acid.

The E horizon has hue of 5YR, 7.5YR, 10YR, or 2.5Y; value from 4 to 6; and chroma of 1 or 2. The Bs horizon has hue of 5YR, 7.5YR, or 10YR; value from 3 to 5; and chroma from 2 to 4.

The C horizon has hue of 7.5YR, 10YR, 2.5Y, or 5Y; value from 3 to 5; and chroma from 2 to 4. Texture is dominantly silt loam, but ranges to include fine sandy loam or sandy loam. Coarse fragment content ranges from 0 to 15 percent.

The texture of the 2C horizon is silt loam or sandy loam. Coarse fragment content ranges from 15 to 30 percent and includes a few large stones.

COMPETING SERIES: These are the Bernice, Boulder Point, Cohoe, Darling, Flat Horn, Kenai, Kroto, Strandline, Swanson(T), Tuomi(T), and Whitsol series in the same subgroup. Bernice soils are sandy-skeletal throughout. Boulder Point, Cohoe, Darling, Flat Horn, Kenai, Kroto, Strandline, Swanson, Tuomi, and Whitsol soils have solums thicker than 7 inches.

GEOGRAPHIC SETTING: The Naptowne soils are on moraines and mountain sideslopes. They formed in an admixture of volcanic ash and silt loam overlying glacial till. The climate is transitional between maritime and continental. The average annual precipitation ranges from 16 to 28 inches. Mean annual temperature ranges from 33 to 36 degress F. Slopes range from 0 to 45 percent.

DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderate. Slow to rapid runoff.

USE AND VEGETATION: Used for timber production, wildlife habitat, recreation, pasture, hay, and cropland. Native vegetation is white spruce, paper birch, and aspen forest.

DISTRIBUTION AND EXTENT: Southcentral Alaska. The series is of moderate extent. SERIES ESTABLISHED: Kenai - Kasilof Area, Alaska. 1960.

REMARKS: Diagnostic horizons and features recognized in this profile include: a spodic horizon from 1 to 5 inches; cryic temperature regime, the exchange complex of the control section from 10 to 19 inches is dominated by amorphous material; the control section from 19 to 40 inches averages coarse-loamy in particle size; the solum is less than 7 inches thick.

The Naptowne series formerly classified as coarse-loamy. The exchange complex of the upper part of the control section, however, is dominated by amorphous material and is at least 4 inches thick. Also, the solum is less than 7 inches thick.

National Cooperative Soil Survey
U.S.A.

Contact: Mike Gracz Kenai Watershed Forum  PO Box 15301 Fritz Creek, AK  99603 907-235-2218

04 May 2007 10:23