LOCATION NAGRUK                  AK

Established Series
SAS/CBB
11/2024

NAGRUK SERIES

Depth class: moderately deep to bedrock, paralithic
Drainage class: moderately well drained
Parent material: organic material over loamy slope alluvium over gravelly loamy residuum weathered from limestone, sandstone, and shale
Landscape: mountains
Landform: mountain slopes, saddles
Slopes: 0 to 20 percent
Mean annual precipitation: about 450 mm (18 in)
Mean annual air temperature: about -4 degrees C. (25 degrees F.)
Frost-free period: 70 to 85 days

TAXONOMIC CLASS: Fine-loamy, mixed, active Aquic Haplocryepts

TYPICAL PEDON: Nagruk parachannery muck in a lichen and willow shrubland on a north facing linear, convex summit on a slope of 3 percent at an elevation of 488 m (1,602 ft)

Oe--0 to 4 cm (0 to 2 in); moderately decomposed plant material, dark reddish brown (5YR 2.5/2) broken face moist, dark reddish gray (5YR 4/2) broken face dry; many very fine and common fine roots throughout; strongly acid (pH 5.4); clear smooth boundary. (2 to 6 cm, 1 to 2 in thick)

Oa/Agjj--4 to 27 cm (2 to 11 in); parachannery muck, 60 percent black (10YR 2/1) broken face and 40 percent very dark gray (7.5YR 3/1) broken face moist, 60 percent dark gray (10YR 4/1) broken face and 40 percent gray (7.5YR 5/1) broken face dry; many very fine and few fine roots throughout; 5 percent channers, 15 percent parachanners ; positive to alpha-alpha dipyridyl; slightly acid (pH 6.3); clear smooth boundary. (20 to 26 cm, 8 to 10 in thick)

A--27 to 39 cm (11 to 15 in); parachannery highly organic silt, black (7.5YR 2.5/1) broken face moist, dark gray (7.5YR 4/1) broken face dry; weak fine granular structure; very friable, soft, nonsticky, nonplastic; nonsmeary; common very fine and few roots throughout; very fine irregular and dendritic tubular pores; 5 percent channers, 15 percent parachanners; noneffervescent; slightly acid (pH 6.3); abrupt irregular boundary. (6 to 15 cm, 2 to 6 in thick)

Bw--39 to 63 cm (15 to 25 in); loam, dark gray (2.5Y 4/1) broken face moist, gray (2.5Y 6/1) broken face dry; strong medium lenticular structure; friable, slightly hard, nonsticky, slightly plastic; nonsmeary; common very fine and fine roots throughout; very fine irregular and dendritic tubular pores; 3 percent distinct silt coats on all faces of peds; 10 percent coarse, irregular, noncoherent dark yellowish brown (10YR 4/4), moist, masses of oxidized iron with clear boundaries around rock fragments; noneffervescent; slightly acid (pH 6.2); clear smooth boundary. (15 to 30 cm, 6 to 12 in thick)

2C--63 to 78 cm (25 to 31 in); very channery loam, dark grayish brown (10YR 4/2) broken face moist, light brownish gray (10YR 6/2) broken face dry; massive; very friable, soft, slightly sticky, slightly plastic; nonsmeary; very fine irregular and dendritic tubular pores; 5 percent coarse, irregular, noncoherent dark yellowish brown (10YR 4/6), moist, masses of oxidized iron with clear boundaries around rock fragments; 45 percent channers; slight effervescence; neutral (pH 6.9); clear irregular boundary. (10 to 45 cm, 4 to 18 in thick)

2Cr--78 to 103 cm (31 to 41 in); extremely weakly to moderately coherent limestone, sandstone, and shale bedrock. (25 cm, 10 in thick)

TYPE LOCATION: Nulato Hills - Continental Divide and Blackburn Hills Soil Survey Area, Alaska; latitude 65 degrees 23 minutes 17.05 seconds north, longitude 160 degrees 0 minutes 37.11 seconds west, datum WGS84, UTM north 7252081.57 and UTM east 453051.12, zone 4W, datum WGS84.

RANGE IN CHARACTERISTICS:

Soil moisture regime: udic
Soil temperature regime: cryic
Mean annual soil temperature: -0.5 to 2.5 degrees C. (31 to 36 degrees F.)
Thickness of organic material: 22 to 32 cm (9 to 13 in)
Thickness of histic epipedon: 2 to 32 cm (1 to 13 in)
Thickness of cambic horizon: 22 to 77 cm (9 to 30 in)
Depth to redoximorphic concentrations: 28 to 122 cm (11 to 48 in)
Depth to aquic conditions: 2 to 6 cm (1 to 2 in)
Depth to lithologic discontinuity: 43 to 77 cm (17 to 30 in)
Depth to paralithic contact: 50 to 100 cm (20 to 40 in)

Oe horizon:
Hue: 5YR, 7.5YR, or 10YR
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: very strongly acid (pH 4.5 to 5.0)

Oa/Agjj horizon:
Hue: 10YR, 7.5YR, or 5YR
Value: 2 to 3 moist, 4 to 5 dry
Chroma: 1 to 2
Texture: muck, channery muck, or parachannery muck
Rock fragments: 0 to 25 percent
Channers: 0 to 25 percent
Parachanners: 0 to 20 percent
Organic matter: 60 to 90 percent
Reaction class: strongly acid to slightly acid (pH 5.1 to 6.5)

A horizon:
Hue: 7.5YR, 10YR, or 2.5Y
Value: 2 to 4 moist, 4 to 6 dry
Chroma: 1 to 3
Texture: highly organic silt, silt loam, or their parachannery analogues
Sand: 0 to 30 percent
Silt: 62 to 97 percent
Clay: 3 to 8 percent
Rock fragments: 0 to 25 percent
Channers: 0 to 25 percent
Parachanners: 0 to 20 percent
Organic matter: 10 to 19 percent
Reaction class: moderately acid to neutral (pH 5.6 to 7.3)

Bw horizon:
Hue: 2.5Y, 10YR, or 5Y
Value: 3 to 4
Chroma: 1 to 3
Texture: loam, clay loam, or sandy clay loam
Sand: 20 to 65 percent
Silt: 15 to 53 percent
Clay: 15 to 28 percent
Organic matter: 0.5 to 3 percent
Reaction class: moderately acid to slightly acid (pH 5.6 to 6.5)

2C horizon:
Hue: 10YR, 2.5Y, or 5Y
Value: 4 to 5 moist, 6 to 7 dry
Chroma: 1 to 3
Texture: very or extremely channery loam or sandy clay loam
Sand: 35 to 65 percent
Silt: 7 to 47 percent
Clay: 18 to 28 percent
Rock fragments: 35 to 75 percent
Channers: 35 to 75 percent
Organic matter: 0.4 to 2 percent
Reaction class: moderately acid to neutral (pH 5.6 to 7.3)

2Cr horizon
Extremely weakly to moderately coherent limestone, sandstone, and shale bedrock.

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING:
Elevation: 330 to 750 meters (1,080 to 2,460 feet)
Parent material: organic material over loamy slope alluvium over gravelly loamy residuum weathered from limestone, sandstone, and shale
Landform: mountain slopes, saddles
Slopes: 0 to 20 percent
Mean annual precipitation: 400 to 600 mm (16 to 24 in)
Mean annual air temperature: -6 to -2 degrees C. (21 to 28 degrees F.)
Frost free period: 70 to 85 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Kalasikcreek and Kikku soils.
Kalasikcreek soilshave an ochric epipedon, a gelic temperature regime, and occur on similar landforms on summit and shoulder positions.
Kikku soils have a reduced matrix at depths between 20 to 200 cm (8 to 79 in), a gelic temperature regime, and occur on similar landforms on shoulder and backslope positions.

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

USE AND VEGETATION:
Use: wildlife habitat, recreation, and subsistence
Native vegetation: splendid feather moss, Flavocetraria culcullata, netleaf willow, dicranum moss, greygreen reindeer lichen, bluejoint, black crowberry, witch's hair lichen, Richardson's willow, glaucous bluegrass, white arctic mountain heather, tealeaf willow, snow lichen, northern singlespike sedge, narrowleaf singlespike sedge, narrowleaf saw-wort, arctic willow, bog blueberry, lingonberry, variegated sedge, sedge, field horsetail, and Barclay's willow.

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: 52 to 78 cm (20 to 31 in)

Histic epipedon: 4 to 27 cm (2 to 11 in) (Oa/Agjj horizon)

Cambic horizon: 27 to 63 cm (11 to 25 in) (A and Bw horizons)

Redoximorphic concentrations: 39 to 78 cm (15 to 31 in) (Bw and 2C horizons)

Lithologic discontinuity: 63 to 103 cm (25 to 41 in) (2C and 2Cr horizons)

Paralithic contact: 78 cm (31 in) (2Cr horizon)

ADDITIONAL DATA:

User pedon ID: 2023AK180251

KSSL lab pedon: S2021AK290613, S2021AK290913, S2021AK290914 (select horizon data)

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National Cooperative Soil Survey
U.S.A.