LOCATION DIRRANT                 AK

Established Series
Rev. MHC/DLM
02/2022

DIRRANT SERIES

Depth class: shallow to permafrost
Drainage class: very poorly drained
Landforms: till plains
Parent material: silty eolian deposits over gravelly alluvium
Elevation: 387 to 778 feet
Slope: 0 to 6 percent
Annual precipitation: 21 to 29 inches
Annual temperature: 24.8 degrees F
Frost-free period: 60 to 90 days

TAXONOMIC CLASS:

TYPICAL PEDON: Dirrant peat- on a slope of 4 percent under sedge/lichen dwarf scrub. (All colors are for moist soil)

Oi--0 to 5 inches; dark yellowish brown (10YR 3/4) peat; many very fine and fine roots; very strongly acid (pH 5.1); gradual smooth boundary.

Oe--5 to 13 inches; very dark brown (10YR 2/2) mucky peat; many very fine and fine roots; very strongly acid (pH 5.2); abrupt smooth boundary.

Cg--13 to 17 inches; very dark gray (5Y 3/1) gravelly loam; friable, nonsticky and nonplastic; few very fine and fine roots; 15 percent gravel, 2 percent cobbles; strongly acid (pH 5.2); abrupt smooth boundary.

Cgf--17 to 60 inches; very dark gray (5Y 3/1) permanently frozen gravelly loam; 15 percent gravel, 2 percent cobbles; moderately acid (pH 5.6).

TYPE LOCATION: Steward River Training Site, Alaska; UTM coordinates: Zone 3, Easting 469828, Northing 7184175

RANGE IN CHARACTERISTICS:

Range in Characteristics
Soil moisture class: aquic
Average annual soil temperature: about 31 degrees F.
Mean summer soil temperature: about 35 degrees F.
Depth to permafrost: 16 to 29 inches
Mica content: visible, but less than 25 percent by weight

Oi, Oe horizon:
Hue: 2.5YR to 10YR
Value: 2 to 3
Chroma: 2 to 4
Texture: peat, mucky peat
Organic matter content: 65 to 90 percent
Rock fragments: 0 to 5 percent rounded indurated gravel
*#Reaction: strongly acid to slightly acid

Cg horizon:
Hue: 5Y or 10Y
Value: 2.5 or 3
Chroma: 1 or 2
Texture: cobbly sandy loam, very cobbly sandy loam, gravelly loam
Clay content: 5 to 25 percent
Silt content: 10 to 45 percent
Sand content: 40 to 75 percent
Organic matter content: 0 to 1 percent
Rock fragments: 0 to 30 percent subangular very strongly cemented gravel, 0 to 5 percent subangular very strongly cemented cobbles
Reaction: very strongly acid to slightly acid

Cgf horizon:
Hue: 5Y or 10Y
Value: 2.5 or 3
Chroma: 1 or 2
Texture: cobbly sandy loam; gravelly loam; loam
Clay content: 5 to 25 percent
Silt content: 10 to 45 percent
Sand content: 40 to 75 percent
Rock fragments: 0 to 30 percent subangular very strongly cemented gravel, 0 to 5 percent subangular very strongly cemented cobbles
Reaction: strongly acid to slightly acid

COMPETING SERIES: This is Boldrin and Kuswash series Boldrin and Kuswash soils lack visible mica.

GEOGRAPHIC SETTING:
Landforms: till plains
Parent material: silty eolian deposits over gravelly alluvium
Elevation: 387 to 778 feet
Slope: 0 to 6 percent
Annual precipitation: 21 to 29 inches
Annual temperature: 24.8 degrees F
Frost-free period: 60 to 90 days

GEOGRAPHICALLY ASSOCIATED SOILS: These include Distin, Imuruk, and Tisuk soils. Distin soils are poorly drained, moderately deep to very deep to permafrost, and occur on circles on till plains. Imuruk soils are very deep, somewhat excessively drained, and occur on hills and outwash plains. Tisuk soils are well drained, very deep, and occur on hills, mountain, and till plains.

DRAINAGE AND PERMEABILITY: Very poorly drained, very high runoff. Saturated hydraulic conductivity is high to very high in the organic layers, moderately high to high upper part of the underlying layer, and very low in the permafrost.

USE AND VEGETATION: Used for military use and wildlife habitat. Native vegetation is sedge/lichen dwarf scrub.

DISTRIBUTION AND EXTENT: MLRA 240, Nulato Hill-Southern Seaward Peninsula Highlands, Alaska. The series is of small extent.

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

SERIES ESTABLISHED: Steward River Training Site, Alaska, 2005

REMARKS: Diagnostic features and horizons recognized in this profile include:
Depth to permafrost: 17 to 60 inches. (Cgf horizon)
Histic epipedon: 0 to 13 inches. (Oi and Oe horizons)
Gleyed horizon: 13 to 60 inches. (Cg and Cgf horizons)
Coarse-loamy particle size control section: 10 to 40 inches below the mineral soil surface
Temperature regime: pergelic

ADDITIONAL DATA:

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National Cooperative Soil Survey
U.S.A.