LOCATION NIILGIK AK

Established Series
SAS/MPS
11/2024

NIILGIK SERIES

Depth class: very deep (moderately deep to permafrost)
Drainage class: poorly drained
Parent material: organic material over silty slope alluvium derived from metamorphic and sedimentary rock
Landscape: mountains
Landform: mountain slopes
Slopes: 1 to 18 percent
Mean annual precipitation: about 500 mm (20 in)
Mean annual air temperature: about -3 degrees C. (27 degrees F.)
Frost-free period: 75 to 90 days

TAXONOMIC CLASS: Coarse-silty, mixed, superactive, acid, subgelic Typic Histoturbels

TYPICAL PEDON: Niilgik peat in a tussock tundra with lichen community on a northwest facing convex, linear footslope on a slope of 5 percent at an elevation of 437m (1434 ft)

Oi--0 to 17 cm (0 to 7 in); peat; dark yellowish brown (10YR 3/6) moist, yellowish brown (10YR 5/6) dry; many very fine and fine roots throughout; noneffervescent; extremely acid (pH 4.0); abrupt smooth boundary. (10 to 18 cm, 4 to 7 in thick)

Oe--17 to 37 cm (7 to 15 in); mucky peat; very dark brown (7.5YR 2.5/2) moist, brown (7.5YR 4/2) dry; many very fine roots throughout; noneffervescent; very strongly acid (pH 4.6); very abrupt smooth boundary. (10 to 21 cm, 4 to 8 in thick)

Cg/Ajj--37 to 55 cm (15 to 22 in); very fine sandy loam; 55 percent gray (2.5Y 5/1) and 45 percent black (7.5YR 2.5/1) moist, 55 percent light gray (2.5Y 7/1) and 45 percent dark gray (7.5YR 4/1) dry; massive and weak fine granular structure; friable, slightly hard, nonsticky, slightly plastic; nonfluid; few very fine roots throughout; common very fine tubular pores; 1 percent fine prominent cylindrical dark yellowish brown (10YR 4/6), moist, masses of oxidized iron on surfaces along root channels; noneffervescent; very strongly acid (pH 4.8); clear smooth boundary. (15 to 40 cm, 6 to 16 in thick)

Cgf--55 to 80 cm (22 to 32 in); permanently frozen silt loam; dark gray (2.5Y 4/1) moist, gray (2.5Y 6/1) dry; massive; extremely firm , nonsticky, slightly plastic; nonfluid; common very fine tubular pores; 3 percent fine prominent irregular strong brown (7.5YR 4/6), moist, masses of oxidized iron at top of horizon; 30 percent 3 mm thick ice lenses; 15 percent pore ice; noneffervescent; very strongly acid (pH 5.0); clear smooth boundary. (15 to 45 cm, 6 to 18 in thick)

Cf--80 to 200 cm (32 to 79 in); permanently frozen silt loam; dark gray (2.5Y 4/1) moist, gray (2.5Y 6/1) dry; massive; extremely firm, nonsticky, slightly plastic; nonfluid; few very fine irregular pores; noneffervescent; very strongly acid (pH 5.0).

TYPE LOCATION: Nulato Hills - Continental Divide and Blackburn Hills Soil Survey Area, Alaska; latitude 64.2281880, longitude -159.649995, datum WGS84, UTM north 7122603.26 and UTM east 468467.28, zone 4, datum WGS84.

RANGE IN CHARACTERISTICS:

Soil moisture regime: aquic
Soil temperature regime: gelic
Mean annual soil temperature: -2 to -1 degrees C. (28 to 30 degrees F.)
Thickness of histic epipedon: 20 to 39 cm (8 to 15 in)
Depth to redoximorphic concentrations: 20 to 39 cm (8 to 15 in)
Depth to reduced matrix: 20 to 39 cm (8 to 15 in)
Depth to cryoturbation: 20 to 39 cm (8 to 15 in)
Depth to permafrost: 50 to 100 cm (20 to 40 in)

Oi and Oe horizons:
Hue: 7.5YR or 10YR
Value: 2 to 3 moist, 4 or 5 dry
Chroma: 1 to 6
Texture: peat, mucky peat
Organic matter: 60 to 90 percent
Reaction class: extremely acid to strongly acid (pH 3.5 to 5.4)

Cg/Ajj horizon:
Hue: 7.5YR, 10YR, 2.5Y
Value: 2.5 to 5 moist, 4 to 7 dry
Chroma: 1 to 3
Texture: silt loam, very fine sandy loam
Sand: 10 to 60 percent
Silt: 23 to 80 percent
Clay: 6 to 17 percent
Organic matter: 0.4 to 5 percent
Reaction class: extremely acid to strongly acid (pH 3.5 to 5.4)

Cgf and Cf horizons:
Hue: 2.5Y
Value: 4 or 5 moist, 6 or 7 dry
Chroma: 1 or 2
Texture: permanently frozen silt loam, permanently frozen very fine sandy loam
Sand: 10 to 60 percent
Silt: 23 to 80 percent
Clay: 5 to 17 percent
Organic matter: 0.4 to 3 percent
Reaction class: very strongly acid to strongly acid (pH 4.5 to 5.4)

Some pedons lack a Cf horizon or have cryoturbated combination horizons other than Cg/Ajj.

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING:
Elevation: 25 to 600 meters (82 to 1969 feet)
Parent material: organic material over silty slope alluvium derived from metamorphic and sedimentary rock
Landform: mountain slopes
Slopes: 1 to 18 percent
Mean annual precipitation: 300 to 600 mm (12 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 Aginaktuk, Apun, Asriavik, Jacksoncreek, Ottercreek, Siku, and Stovecreek soils.
Aginaktuk soils have a thicker organic surface, lack cryoturbation, lack permafrost, have a cryic soil temperature regime, have a pH range of 5.1 to 7.3, and occur on depressions on terraces
Apun soils have a coarse-loamy particle size class, have a nonacid reaction class, and occur on footslopes, terraces and saddles
Asriavik soils lack aquic conditions, lack permafrost, have a folistic epipedon, have a cambic horizon, lack cryoturbation, have a loamy-skeletal over sandy or sandy-skeletal particle size class, and occur on terrace treads
Jacksoncreek soils lack permafrost, have a cambic horizon, have a coarse-loamy particle size class, have an isotic mineralogy class, and occur on terraces and earth hummocks on terraces
Ottercreek soils lack permafrost, have an ochric epipedon, lack cryoturbation, have a nonacid reaction class, have a coarse-loamy particle size class, have a cryic soil temperature regime, and occur on similar landforms on footslopes
Siku soils lack permafrost, have a folistic epipedon, have a cambic horizon, lack cryoturbation, have a loamy-skeletal particle size class, and occur on mountainflanks, upper, center, and lower thirds
Stovecreek soils lack permafrost, have an umbric epipedon, lack cryoturbation, lack an organic surface, have a coarse-loamy particle size class, have an isotic mineralogy class, have a nonacid reaction class, and occur on drainageways

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class: poorly drained
Saturation during normal years-- saturated between 0 and 25 cm during the growing season
Saturated Hydraulic Conductivity: moderately high to high in the Oi, Oe, and Cg/Ajj horizons, and very low to low in the Cgf and Cf horizons
Permeability: moderate to moderately rapid in the Oi, Oe, and Cg/Ajj horizons, and very slow in the Cgf and Cf horizons
Runoff: very high

USE AND VEGETATION:
Use: wildlife habitat, recreation, and subsistence
Native vegetation: tussock cottongrass, reindeer lichen, sphagnum, Bigelow's sedge, bog blueberry, Flavocetraria cucullata, dwarf birch, Schreber's big red stem moss, cloudberry

DISTRIBUTION AND EXTENT: MLRA 240, Nulato Hills-Southern Seward Peninsula Highlands. The series is of moderate 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: 62 to 137 cm (24 to 54 in)

Histic epipedon: 0 to 37 cm (0 to 15 in) (Oi and Oe horizons)

Cryoturbation: 37 to 55 cm (15 to 22 in) (Cg/Ajj horizon)

Gelic materials: 37 to 80 cm (15 to 31 in (Cg/Ajj and Cgf horizons)

Reduced matrix: 37 to 80 cm (15 to 31 in) (Cg/Ajj and Cgf horizons)

Redoximorphic concentrations: 37 to 80 cm (15 to 31 in) (Cg/Ajj and Cgf horizons)

Permafrost 55 to 200 cm (22 to 79 in) (Cgf and Cf horizons)

Aquic conditions: 0 to 80 cm (0 to 31 in) (Oi, Oe, Cg/Ajj, and Cgf horizons)

ADDITIONAL DATA:

User pedon ID: 2022AK290531

National Cooperative Soil Survey
U.S.A.