LOCATION COHOE              AK
Established Series
Rev. RBH/SR/DLM
03/2005

COHOE SERIES


Depth class: very deep
Drainage class: well drained
Parent material: ash influenced loess over glaciolacustrine deposits
Landform: moraines on till plains
Slopes: 0 to 60 percent
Mean annual precipitation: 15 to 30 inches.
Mean annual temperature: 33 to 36 degrees F.

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

TYPICAL PEDON: Cohoe silt loam on a 4 percent slope forest at 397 feet (121 meter) (All colors are for moist soil)

Oe--0 to 2 inches (0 to 6 cm); very dark brown (10YR 2/2) moderately decomposed plant material; common very fine, fine roots, and medium roots; very strongly acid (pH 4.8); abrupt wavy boundary. (0 to 5 inches (0 to 13 cm) thick)

E--2 to 4 inches (6 to 11 cm); brown (10YR 5/3) and dark grayish brown (10YR 4/2) silt loam; weak fine granular structure; very friable, nonsticky and nonplastic; common very fine, fine, and medium roots; very strongly acid (pH 4.7); abrupt wavy boundary. (1 to 3 inches (2 to 8 cm) thick)

Bs--4 to 8 inches (11 to 20 cm); brown (7.5YR 4/4) silt loam; weak fine subangular blocky structure; very friable, nonsticky and nonplastic; common very fine, fine, and medium roots; strongly acid (pH 5.1); clear wavy boundary. (2 to 10 inches (5 to 25 cm) thick)

Bw1--8 to 14 inches (20 to 35 cm); dark yellowish brown (10YR 4/4) silt loam; weak very fine subangular blocky structure; very friable, nonsticky and nonplastic; common very fine, fine, and medium roots; strongly acid (pH 5.3); gradual wavy boundary.

Bw2--14 to 24 inches (35 to 60 cm); olive brown (2.5Y 4/4) and dark yellowish brown (10YR 4/4) silt loam; weak very fine subangular blocky structure; very friable, nonsticky and nonplastic; common very fine, fine, and medium roots; strongly acid (pH 5.5); clear wavy boundary. (Combined thickness of the Bw horizons is 6 to 30 inches (15 to 80 cm))

2BC1--24 to 34 inches (60 to 86 cm); light olive brown (2.5Y 5/3) silt loam; very weak very fine angular blocky structure; very friable, nonsticky and nonplastic; common very fine, fine, and medium roots; moderately acid (pH 5.7); gradual wavy boundary.

2BC2--34 to 52 inches (86 to 133 cm); light olive brown (2.5Y 5/3) silt loam; very weak very fine angular blocky structure; very friable, nonsticky and nonplastic; 1 percent gravel; moderately acid (pH 6.0); abrupt wavy boundary. (Combined thickness of the 2BC horizons is 0 to 29 inches (0 to 73 cm))

3C1--52 to 58 inches (133 to 149 cm); dark olive gray (5Y 3/2) gravelly sand; single grained; loose, nonsticky and nonplastic; 19 percent gravel; moderately acid (pH 6.0); abrupt wavy boundary. (3 to 12 inches (7 to 30 cm) thick)

3C2--58 to 72 inches (149 to 185 cm); olive gray (5Y 4/2) very gravelly fine sandy loam; massive; friable, nonsticky and nonplastic; 40 percent gravel, 5 percent cobbles; slightly acid (pH 6.2).

TYPE LOCATION: Kenai-Kasilof Area, Alaska. NW 1/4, SE 1/4, NW 1/4, section 34, T. 1S., R. 13W., Seward Meridian; UTM north 6657877 and UTM east 583422, zone 5 about 5 miles west of Ninilchik.

RANGE IN CHARACTERISTICS:
Loess thickness: 20 to greater than inches 30 (50 to 75 cm)
Ash thickness: 15 to 25 inches (40 to 65 cm)
Particle size control section (weighted average): less than 15 percent fine sands and coarser
Depth to glaciolacustrine deposits: greater than 30 inches (75 cm); upper part has silt loam or very fine sandy loam textures with less than 15 percent coarse fragments
Depth to gravelly, very gravelly material, or sand textures: greater than 40 inches (100 cm)

O horizon:
Matrix color: hue of 5YR to 10YR; value of 2 to 4; chroma of 1 or 2
Texture: slightly decomposed plant material, moderately decomposed plant material
Reaction class: extremely acid to strongly acid

E horizon:
Matrix color: hue of 7.5YR or 10YR; value of 4 or 5; chroma of 1 or 2
Texture: silt loam, very fine sandy loam
Reaction class: very strongly acid or strongly acid
Coarse white grains of sand size volcanic ash are commonly mixed with the E horizon

Bs horizon:
Matrix color: hue of 2.5YR; value of 3 or 4; chroma of 4 to 6
Texture silt loam, very fine sandy loam
Reaction class: very strongly acid or strongly acid

Bw horizon:
Matrix color: hue of 10YR or 2.5Y; value of 3 to 5; chroma of 2 to 6
Texture: silt loam, very fine sandy loam
Reaction class: strongly acid or moderately acid

2BC horizon:
Matrix color: 10YR or 2.5Y: value of 4 or 5; chroma of 2 to 4
Texture: silt loam, very fine sandy loam
Coarse fragments: 0 to 10 percent gravel; 0 to 5 percent cobbles
Reaction class: strongly acid or moderately acid

3C horizon:
Matrix color: hue of 10YR to 5Y; value of 3 to 5; chroma of 1 to 3
Texture: sandy loam, loam, silt loam, sand modified by 0 to 50 percent total Coarse fragments; 0 to 40 percent gravel; 0 to 10 percent cobbles
Reaction class: moderately or slightly acid

COMPETING SERIES: These are the Kenai, Mutnala, Naptowne, and Whitsol series. Kenai soils have more than 18 percent clay in the loamy part control section. Mutnala and Naptowne soils have a weighted average of greater than 15 percent fine sands and coarser and are bisequal. Whitsol soils have stratified textures in the substratum.

GEOGRAPHIC SETTING:
Depth class: very deep
Drainage class: well drained
Parent material: ash influenced loess over glaciolacustrine deposits
Landform: moraines on till plains
Slopes: 0 to 60 percent
Climate: maritime with cool summers and long moderately cold winters
Mean annual temperature: 33 to 36 degrees F.
Mean annual precipitation: 15 to 30 inches.

GEOGRAPHICALLY ASSOCIATED SOILS: These include Island, Soldotna, Spenard, and Starichkof soils. Island soils lack albic horizons and occur on subtle depressions. Soldotna soils have sandy or sandy-skeletal substratums. Spenard soils are poorly drained mineral soils in shallow depressions. Starichkof soils are poorly drained peat soils occupying bogs.

DRAINAGE AND PERMEABILITY: Well drained, low to high runoff. Saturated hydraulic conductivity is high in the upper part of the solum, moderately high or high in the lower part of the solum, and high to very high in the substratum.

USE AND VEGETATION: Some areas have been cleared and used for potatoes,
hardy vegetables, hay, and pasture. The natural vegetation is an open growing Lutz spruce paper birch and balsam poplar, and a understory of bluejoint grass and associated forbs and shrubs.

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

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon

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

REMARKS: Diagnostic features and horizons recognized in this profile include:
Albic horizon: 2 to 4 inches (6 to 11 cm)
Spodic horizon: 4 to 8 inches (11 to 20 cm)
Andic material: 2 to 14 inches (6 to 35 cm)
Loamy material: 14 to 40 inches (35 to 100 cm)
Medial mineralogy: 4 to 14 inches (11 to 35 cm)
Mixed mineralogy: 14 to 40 inches (35 to 100 cm)
Temperature regime: cryic
Moisture regime: udic

ADDITIONAL DATA: This profile was sampled in 2001 as S01AK-122005 Western Kenai Peninsula Area, Alaska, National Cooperative Soil Survey. 87AK-122-008


National Cooperative Soil Survey
U.S.A.