LOCATION SAGVAKTUK               AK

Established Series
SWD/CBB
11/2024

SAGVAKTUK SERIES

Depth class: very deep
Drainage class: well drained
Parent material: loamy slope alluvium over gravelly loamy colluvium derived from sedimentary rock
Landscape: mountains
Landform: drainageways, valleys
Slopes: 2 to 15 percent
Mean annual precipitation: about 500 mm (20 in)
Mean annual air temperature: about -4 degrees C. (25 degrees F.)
Frost-free period: 70 to 85 days

TAXONOMIC CLASS: Coarse-loamy, isotic Typic Haplocryepts

TYPICAL PEDON: Sagvaktuk silt loam in a tealeaf willow and bluejoint community on a southwest facing concave, linear footslope on a slope of 3 percent at an elevation of 466 m (1,530 ft)

Oe--0 to 5 cm (0 to 2 in); moderately decomposed plant material, very dark brown (10YR 2/2) moist, dark grayish brown (10YR 4/2) dry; many very fine and coarse and few fine roots throughout; very strongly acid (pH 4.7); abrupt smooth boundary. (1 to 10 cm, 0.5 to 4 in thick)

A--5 to 10 cm (2 to 4 in); silt loam, black (10YR 2/1) moist, dark gray (10YR 4/1) dry; weak fine granular structure; friable, slightly hard, nonsticky, nonplastic; nonsmeary; common very fine and fine and few medium roots throughout; very fine dendritic tubular pores; 5 percent gravel; moderately acid (pH 5.9); abrupt smooth boundary. (3 to 15 cm, 1 to 6 in thick)

Bw--10 to 125 cm (4 to 49 in); cobbly silt loam, very dark gray (2.5Y 3/1) moist, gray (2.5Y 5/1) dry; weak medium subangular blocky structure; friable, slightly hard, nonsticky, nonplastic; nonsmeary; few very fine roots throughout; very fine dendritic tubular pores; 3 percent fine, irregular dark brown (7.5YR 3/4) masses of oxidized iron in matrix; 10 percent gravel and 20 percent cobbles; moderately acid (pH 5.8); abrupt smooth boundary. (35 to 130 cm, 14 to 51 in thick)

2C--125 to 200 cm (49 to 79 in); very cobbly silt loam, dark grayish brown (2.5Y 4/2) moist, light brownish gray (2.5Y 6/2) dry; massive; friable, slightly hard, nonsticky, nonplastic; nonsmeary; very fine irregular pores; 25 percent gravel and 20 percent cobbles; moderately acid (pH 5.9). (45 to 161 cm, 18 to 63 in thick)

TYPE LOCATION: Nulato Hills - Continental Divide and Blackburn Hills Soil Survey Area, Alaska; latitude 64 degrees 40 minutes 18.61 seconds north, longitude 159 degrees 52 minutes 4.59 seconds west, datum WGS84, UTM north 7172165.81 and UTM east 458570.42, 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: 1 to 10 cm (0.5 to 4 in)
Thickness of ochric epipedon: 1 to 10 cm (0.5 to 4 in)
Thickness of cambic horizon: 38 to 145 cm (15 to 57 in)
Depth to redoximorphic concentrations: 4 to 25 cm (2 to 10 in)
Depth to lithologic discontinuity: 39 to 155 cm (15 to 61 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: very strongly acid to moderately acid (pH 4.5 to 6.0)

A horizon:
Hue: 10YR or 7.5YR
Value: 2 to 3 moist, 4 to 5 dry
Chroma: 1 to 3
Texture: silt loam or gravelly silt loam
Sand: 10 to 45 percent
Silt: 50 to 80 percent
Clay: 2 to 10 percent
Rock fragments: 0 to 25 percent
Gravels: 0 to 25 percent
Organic matter: 2 to 8 percent
Reaction class: very strongly acid to moderately acid (pH 4.5 to 6.0)

Bw horizon:
Hue: 2.5Y or 10YR
Value: 3 to 4 moist, 5 to 6 dry
Chroma: 1 to 3
Texture: silt loam and its cobbly and gravelly analogues
Sand: 10 to 45 percent
Silt: 50 to 80 percent
Clay: 2 to 10 percent
Rock fragments: 15 to 45 percent
Gravels: 5 to 20 percent
Cobbles: 5 to 25 percent
Organic matter: 2 to 6 percent
Reaction class: strongly acid to slightly acid (pH 5.1 to 6.5)

2C horizon:
Hue: 2.5Y or 10YR
Value: 3 to 4 moist, 5 to 6 dry
Chroma: 1 to 3
Texture: very cobbly or gravelly silt loam, sandy loam, or coarse sandy loam
Sand: 15 to 70 percent
Silt: 20 to 80 percent
Clay: 2 to 10 percent
Rock fragments: 35 to 59 percent
Gravels: 15 to 50 percent
Cobbles: 5 to 35 percent
Organic matter: 0.4 to 3 percent
Reaction class: strongly acid to slightly acid (pH 5.1 to 6.5)

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING:
Elevation: 330 to 600 meters (1,080 to 1,970 feet)
Parent material: loamy slope alluvium over gravelly loamy colluvium derived from sedimentary rock
Landform: drainageways, valleys
Slopes: 2 to 15 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 Urgiilik, Apun, Muskox, and Egoosikcreek soils.
Urgiilik soils are moderately deep to lithic bedrock at depths between 50 to 100 cm (20 to 40 in) and occur on mountain slopes.
Apun soils have shallow permafrost within 50 cm (20 in) of the surface and occur on mountain slopes.
Muskox soils have an umbric epipedon and occur on swales on mountain slopes.
Egoosikcreek soils have a mollic epipedon and occur on swales.

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

USE AND VEGETATION:
Use: wildlife habitat, recreation, and subsistence
Native vegetation: tealeaf willow, bluejoint, meadow horsetail, splendid feather moss, fireweed, and arctic sweet coltsfoot.

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: 30 to 105 cm (12 to 41 in)

Ochric epipedon: 0 to 10 cm (0 to 4 in) (Oe and A horizons)

Cambic horizon: 5 to 125 cm (2 to 49 in) (A and Bw horizons)

Redoximorphic concentrations: 10 to 125 cm (4 to 49 in) (Bw horizon)

Lithologic discontinuity: 125 to 200 cm (49 to 79 in) (2C horizon)

ADDITIONAL DATA:

User pedon ID: 2021AK290844

---

National Cooperative Soil Survey
U.S.A.