LOCATION UNIAT                   AK

Established Series
ZKA/CBB
11/2024

UNIAT SERIES

Depth class: deep to bedrock, lithic
Drainage class: well drained
Parent material: loamy slope alluvium over gravelly residuum weathered from mudstone
Landscape: mountains
Landform: valleys
Slopes: 1 to 10 percent
Mean annual precipitation: about 550 mm (22 in)
Mean annual air temperature: about -3 degrees C. (27 degrees F.)
Frost-free period: 75 to 90 days

TAXONOMIC CLASS: Fragmental, mixed Typic Dystrocryepts

TYPICAL PEDON: Uniat silt loam in a lichen and low shrub community on a northeast facing convex, linear backslope on a slope of 7 percent at an elevation of 208 m (685 ft)

Oe--0 to 8 cm (0 to 3 in); moderately decomposed plant material, black (10YR 2/1) moist, dark gray (10YR 4/1) dry; nonsmeary; common very fine, fine, medium, and coarse roots throughout; very strongly acid (pH 4.7); clear smooth boundary. (0 to 10 cm, 0 to 4 in thick)

A--8 to 16 cm (3 to 6 in); silt loam, very dark brown (10YR 2/2) moist, dark grayish brown (10YR 4/2) dry; weak medium granular structure; friable, slightly hard, nonsticky, nonplastic; nonsmeary; common very fine, fine, and medium roots throughout; very fine irregular pores; 7 percent channers; strongly acid (pH 5.1); clear wavy boundary. (4 to 16 cm, 2 to 6 in thick)

E--16 to 24 cm (6.3 to 9.4 in); silt, brown (10YR 4/3) moist, pale brown (10YR 6/3) dry; 15 percent coarse, irregular dark reddish brown (5YR 3/4) mottles; moderate medium subangular blocky structure; friable, slightly hard, nonsticky, nonplastic; nonsmeary; common very fine, fine, and medium roots throughout; common very fine and fine irregular pores; 8 percent channers; strongly acid (pH 5.2); clear wavy boundary. (0 to 10 cm, 0 to 4 in thick)

Bw--24 to 33 cm (9 to 13 in); channery silt, 60 percent dark yellowish brown (10YR 4/4) and 40 percent dark yellowish brown (10YR 3/4) moist, 60 percent light yellowish brown (10YR 6/4) and 40 percent yellowish brown (10YR 5/4) dry; weak medium subangular blocky structure; friable, slightly hard, nonsticky, nonplastic; nonsmeary; common fine and medium roots throughout; common very fine and fine irregular pores; 20 percent channers; moderately acid (pH 5.7); abrupt wavy boundary. (6 to 55 cm, 2 to 22 in thick)

2C--33 to 102 cm (13 to 40 in); flagstones; medium, coarse, and very coarse interstitial pores; 20 percent channers and 75 percent flagstones; abrupt wavy boundary (35 to 80 cm, 14 to 31 in thick)

2R--102 to 127 cm (40 to 50 in); strongly coherent to indurated mudstone bedrock.

TYPE LOCATION: Nulato Hills - Continental Divide and Blackburn Hills Soil Survey Area, Alaska; latitude 64 degrees 34 minutes 55.96 seconds north, longitude 160 degrees 30 minutes 5.44 seconds west, datum WGS84, UTM north 7162745.08 and UTM east 428095.03, zone 4W, datum WGS84.

RANGE IN CHARACTERISTICS:

Soil moisture regime: udic
Soil temperature regime: cryic
Mean annual soil temperature: 0 to 3 degrees C. (32 to 37 degrees F.)
Thickness of organic material: 0 to 10 cm (0 to 4 in)
Thickness of ochric epipedon: 4 to 26 cm (2 to 10 in)
Thickness of cambic horizon: 15 to 81 cm (6 to 32 in)
Depth to lithologic discontinuity: 10 to 91 cm (4 to 36 in)
Depth to lithic contact: 100 to 150 cm (40 to 60 in)

Oe horizon:
Hue: 10YR or 7.5YR
Value: 2 to 3 moist, 4 to 5 dry
Chroma: 1 to 2
Texture: moderately decomposed plant material
Organic matter: 60 to 90 percent
Reaction class: extremely acid to very strongly acid (pH 3.5 to 5.0)

A horizon:
Hue: 10YR or 7.5YR
Value: 2 to 3 moist, 4 to 5 dry
Chroma: 1 to 3
Texture: silt loam or channery silt loam
Sand: 15 to 45 percent
Silt: 50 to 80 percent
Clay: 2 to 8 percent
Rock fragments: 0 to 20 percent
Channers: 0 to 20 percent
Organic matter: 2 to 8 percent
Reaction class: very strongly acid to strongly acid (pH 4.5 to 5.5)

E horizon:
Hue: 10YR or 2.5Y
Value: 4 to 5 moist, 6 to 7 dry
Chroma: 2 to 4
Texture: silt or channery silt
Sand: 0 to 18 percent
Silt: 80 to 98 percent
Clay: 2 to 12 percent
Rock fragments: 0 to 20 percent
Channers: 0 to 20 percent
Organic matter: 1 to 5 percent
Reaction class: very strongly acid to strongly acid (pH 4.5 to 5.5)

Bw horizon:
Hue: 10YR or 2.5Y
Value: 3 to 5 moist, 5 to 7 dry
Chroma: 3 to 4
Texture: silt, silt loam and their channery analogues
Sand: 0 to 40 percent
Silt: 50 to 94 percent
Clay: 6 to 12 percent
Rock fragments: 15 to 59 percent
Channers: 15 to 59 percent
Organic matter: 1 to 4 percent
Reaction class: very strongly acid to moderately acid (pH 4.5 to 6.0)

2C horizon:
Texture: or their gravelly analogues
Rock fragments: 90 to 100 percent
Channers: 10 to 50 percent
Flagstones: 40 to 90 percent

2R horizon
Strongly coherent to indurated mudstone bedrock.

Some pedons do not have an E horizon and/or have gravels and cobbles in the substratum.

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING:
Elevation: 480 to 700 meters (1,575 to 2,300 feet)
Parent material: loamy slope alluvium over gravelly residuum weathered from mudstone
Landform: valleys
Slopes: 1 to 10 percent
Mean annual precipitation: 500 to 600 mm (20 to 24 in)
Mean annual air temperature: -5 to -1 degrees C. (23 to 30 degrees F.)
Frost free period: 75 to 90 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Umilguk, Buck, Diamondcreek, Savik, Debauch, Silagiksaak, and Apun soils.
Umilguk soils have a mollic epipedon, aquic conditions at depths below 30 to 63 cm (12 to 25 in), and occur on hillslopes on backslopes and footslopes.
Buck soils have andic soil properties at depths between 1 to 85 cm (0.5 to 33 in) and occur on ridges of hills.
Diamondcreek soils have an umbric epipedon, a reduced matrix and redox concentrations at depths below 16 to 44 cm (6 to 17 in), and occur on swales of hillslopes.
Savik soils have an umbric epipedon, are shallow to paralithic contact at depths between 25 to 50 cm (10 to 20 in), and occur on mountain slopes on shoulders and uppper backslope positions.
Debauch soils do not have a cambic horizon, are shallow to paralithic bedrock at depths between 25 to 50 cm (10 to 20 in), and occur on mountain ridges.
Silagiksaak soils have redox concentrations and depletions at depths between 13 to 200 cm (5 to 79 in) and occur on mountain slopes on summit, shoulder, and backslope positions.
Apun soils have permafrost within 50 cm (20 in) and occur on mountain slopes on footslope positions.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class: well drained
Saturated Hydraulic Conductivity: very high in the Oe and 2C horizons and moderately high in the A, E, and Bw horizons
Permeability: rapid to very rapid in the Oe horizon; moderate in the A, E, and Bw horizons; and very rapid in the 2C horizon
Runoff: low or medium

USE AND VEGETATION:
Use: wildlife habitat, recreation, and subsistence
Native vegetation: reindeer lichen, star reindeer lichen, small cranberry, black crowberry, bluejoint, lingonberry, dwarf birch, marsh Labrador tea, polytrichum moss, white spruce, arctic kidney lichen, grayleaf willow, and tealeaf willow.

DISTRIBUTION AND EXTENT: MLRA 240, Nulato Hills-Southern Seward Peninsula Highlands. The series is of small extent.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Wasilla, Alaska

SERIES ESTABLISHED: Nulato Hills - Continental Divide and Blackburn Hills Soil Survey, Alaska, 2024.

REMARKS: Diagnostic features and horizons recognized in this profile include:

Particle-size control section: 33 to 102 cm (13 to 40 in)

Ochric epipedon: 0 to 16 cm (0 to 6 in) (Oe and A horizon)

Cambic horizon: 8 to 33 cm (3 to 13 in) (A, E, and Bw horizons)

Lithologic discontinuity: 33 to 127 cm (13 to 50 in) (2C and 2R horizons)

Lithic contact: 102 to 127 cm (40 to 50 in) (2R horizon)

ADDITIONAL DATA:

User pedon ID: S2021AK180900

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National Cooperative Soil Survey
U.S.A.