LOCATION NAPTOWNE                AK

Established Series
Rev. SR/JPM/DLM
05/2022

NAPTOWNE SERIES

Depth class: very deep
Drainage class: well drained
Parent material: ash influenced loess over gravelly drift
Landform: moraines and till plains
Slopes: 0 to 60 percent
Mean annual precipitation: 16 to 28 inches
Mean annual temperature: 33 to 36 degrees F.

TAXONOMIC CLASS: Medial over loamy, amorphic over mixed, superactive Andic Haplocryods

TYPICAL PEDON: Naptowne silt loam - on a slope of 4 percent under forest vegetation at 102 feet elevation. (All colors are for moist soil unless noted)

Oe--0 to 3 inches; very dark grayish brown (10YR 3/2) moderately decomposed plant material; many very fine, fine, medium, and coarse roots; extremely acid (pH 4.3); abrupt smooth boundary. (1 to 4 inches thick)

E--3 to 4 inches; dark grayish brown (10YR 4/2) silt loam; weak fine granular structure; very friable, nonsticky and nonplastic; many very fine, fine, medium, and coarse roots; smeary; very strongly acid (pH 4.5); abrupt wavy boundary. (1 to 3 inches thick)

Bs1--4 to 9 inches; brown (7.5YR 4/4) silt loam; moderate fine subangular structure; very friable, nonsticky and nonplastic; many very fine, fine, medium, and coarse roots; smeary; very strongly acid (pH 4.7); clear wavy boundary

Bs2--9 to 13 inches; brown (7.5YR 4/4) silt loam; weak fine angular blocky structure; friable, nonsticky and nonplastic; many very fine and fine roots, common medium and coarse roots; smeary; very strongly acid (pH 5.0); clear wavy boundary. (Combined thickness of the Bs horizons is 7 to 14 inches thick)

Bw--13 to 21 inches; dark yellowish brown (10YR 4/4) silt loam; weak fine angular blocky structure; friable, nonsticky and nonplastic; common very fine and fine roots, few medium roots; slightly smeary; very strongly acid (pH 5.0); clear smooth boundary. (6 to 10 inches thick)

2C--21 to 60 inches; olive brown (2.5Y 4/3) very gravelly fine sandy loam; massive; firm, nonsticky and nonplastic; 35 percent gravel; strongly acid (pH 5.5).

TYPE LOCATION: Western Kenai Peninsula Area, Alaska; about 2 miles northeast of Gray Cliff Lake; in the NW 1/4 of the SE 1/4, section 29, T. 9 N., R. 9 W.; Kenai D3 SE 1:25,00 quad; Seward Meridian; UTM north 6746770 and UTM east 613419, zone 5.

RANGE IN CHARACTERISTICS:

Particle-size control (section weighted average): greater than 15 percent fine sands and coarser
Percent clay in the substratum: 0 to 5 percent

Soil moisture regime: udic
Mean annual soil temperature: 34 degrees F
Thickness of solum: 14 to 24 inches
Thickness of loess 14 to 30 inches
Thickness of ash 14 to 24 inches
Depth to gravelly drift: 14 to 30 inches

O horizon:
Matrix color: hue of 10YR or 2.5Y; value of 3 or 4; chroma of 2 to 4
Reaction class: extremely acid to strongly acid

E horizon:
Matrix color: hue of 10YR or 2.5Y; value of 4 or 5; chroma of 1 or 2
Texture: silt loam, very fine sandy loam
Reaction class: very strongly to moderately acid

Bs horizon:
Matrix color: value of 4 or 5; chroma of 3 or 4
Texture: silt loam, very fine sandy loam
Total organic carbon: 2 to 5 percent
Reaction class: very strongly acid to moderately acid

Bw horizon:
Matrix color: hue of 10YR or 2.5Y; value of 3 to 5; chroma of 3 to 6
Texture: silt loam, very fine sandy loam
Coarse fragments: 0 to 10 percent gravel
Reaction class: very strongly acid to slightly acid

2C horizon:
Matrix color: hue of 10YR to 5Y; value of 3 to 5; chroma of 3 to 6
Texture: fine sandy loam, sandy loam, very fine sandy loam, silt loam modified by 15 to 60 total coarse fragment; 0 to 45 percent gravel, 0 to 35 percent cobbles, and 0 to 10 percent stones
Reaction class: strongly acid to slightly acid

COMPETING SERIES: These are the Cohoe, Kenai, Mutnala, and Whitsol series. Cohoe soils have less than 15 percent fine sands and coarser in the upper 40 inches of the soil profile. Kenai soils have greater than 20 percent clay in the substratum. Mutnala soils have greater than 6 percent total carbon in the spodic horizon. Whitsol soils have loess thickness is greater than 40 inches.

GEOGRAPHIC SETTING:
Drainage class: well drained
Parent material: ash influenced loess over gravelly drift
Landform: moraines and till plains
Slopes: 0 to 60 percent
Mean annual temperature: 33 to 36 degrees F.
Mean annual precipitation: 16 to 28 inches

GEOGRAPHICALLY ASSOCIATED SOILS: These are Cohoe, Soldotna, Slikok, and Tuxedni series. Cohoe and Soldotna soils are well drained and occur on similar landforms. Slikok soils are very poorly drained and occur on depressions. Tuxdeni soils are somewhat poorly drained and occur on similar landforms.

DRAINAGE AND PERMEABILITY: Well drained, low to high runoff, saturated hydraulic conductivity is high is the solum and moderately high to high in the substratum.

USE AND VEGETATION: Used for wildlife habitat, timber production, and recreation. The native vegetation is white spruce, paper birch, oakfern, and dogwood.

DISTRIBUTION AND EXTENT: MLRA 224 Cook Inlet Lowland, South-central Alaska, The series is of moderate extent.

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

SERIES ESTABLISHED: Area, Alaska, 1960

REMARKS: Diagnostic features and horizons recognized in this profile include:
Albic horizon: from 3 to 4 inches
Spodic horizon: from 4 to 13 inches
Andic properties: 4 to 21 inches
Temperature regime: cryic

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National Cooperative Soil Survey
U.S.A.