LOCATION IVGICH                  AK

Established Series
MPS
03/2025

IVGICH SERIES

Depth class: very deep
Drainage class: very poorly drained
Parent material: loamy alluvium derived from metamorphic and sedimentary rock over loamy estuarine deposits
Landscape: coastal plains
Landform: depressions on delta plains, abandoned channels on delta plains
Slopes: 0 to 1 percent
Mean annual precipitation: about 350 mm (14 in)
Mean annual air temperature: about -3 degrees C. (27 degrees F.)
Frost-free period: 75 to 90 days

TAXONOMIC CLASS: Fine-loamy, mixed, superactive, nonacid Typic Sulfaquents

TYPICAL PEDON: Ivgich silt loam in a halophytic sedge estuary community on a concave, concave abandoned channel on a slope of 0 percent at an elevation of 3m (10 ft)

Ag--0 to 3 cm (0 to 1 in); silt loam black (10YR 2/1) broken face moist, dark gray (10YR 4/1) broken face dry; weak fine granular structure; friable, slightly hard, nonsticky, nonplastic; nonfluid; many very fine roots and common fine roots throughout; common fine dendritic tubular pores; no odor; positive to alpha-alpha dipyridyl measured in matrix; noneffervescent; neutral (pH 6.7); clear smooth boundary. (1 to 15 cm, 0.5 to 6 in thick)

2Cseg1--3 to 19 cm (1 to 8 in); silt loam; black (N 2.5/), broken face moist, dark gray (N 4/), broken face dry; massive; friable, slightly hard, nonsticky, nonplastic; nonfluid; many very fine roots and common fine roots throughout; common fine dendritic tubular pores; 0 mS of EC; slight sulfurous odor; reduced iron monosulfides present; positive to alpha-alpha dipyridyl measured in matrix; noneffervescent; slightly acid (pH 6.5), extremely acid after 16 weeks (oxidized pH 3.75); clear smooth boundary. (15 to 35 cm, 6 to 14 in thick)

2Cseg2--19 to 60 cm (8 to 24 in); silt loam; greenish black (10Y 2.5/1) broken face moist, dark greenish gray (10Y 4/1) broken face dry; massive; friable, slightly hard, nonsticky, nonplastic; slightly fluid; few very fine roots throughout; common very fine irregular pores; 2.4 mS of EC; slight sulfurous odor; reduced iron monosulfides present; positive to alpha-alpha dipyridyl measured in matrix; noneffervescent; slightly acid (pH 6.3),strongly acid after 16 weeks (oxidized pH 5.5); gradual smooth boundary. (30 to 70 cm, 12 to 28 in thick)

2Cseg3--60 to 200 cm (24 to 79 in); silt loam; greenish black (10Y 2.5/1) broken face moist, dark greenish gray (10Y 4/1) broken face dry; massive; friable, slightly hard, nonsticky, nonplastic; moderately fluid; very few very fine roots at top of horizon; common very fine irregular pores; 10.3 mS of EC; slight sulfurous odor; reduced iron monosulfides present; positive to alpha-alpha dipyridyl measured in matrix; noneffervescent; slightly acid (pH 6.3), very strongly acid after 16 weeks (oxidized pH 4.6)

TYPE LOCATION: Nulato Hills - Continental Divide and Blackburn Hills Soil Survey Area, Alaska; latitude 64.8607580, longitude -160.8504030, datum WGS84, UTM north 7194218.70 and UTM east 412296.96, zone 4, datum WGS84.

RANGE IN CHARACTERISTICS:

Soil moisture regime: peraquic
Soil temperature regime: cryic
Mean annual soil temperature: 0 to 3 degrees C. (32 to 37 degrees F.)
Thickness of ochric epipedon: 1 to 15 cm (0.5 to 6 in)
Depth to sulfidic(hypersulfidic) materials: 1 to 15 cm (0.5 to 6 in)
Depth to hyposulfidic materials 1 to 20 cm (0.5 to 8 in)
Depth to reduced matrix: 1 to 15 cm (0.5 to 6 in)
Depth to n value greater than 0.7: 1 to 20 cm (0.5 to 8 in)

Ag horizon:
Hue: 10YR or 2.5Y
Value: 2 or 3 moist, 4 or 5 dry
Chroma: 1 or 2
Texture: silt loam
Sand: 20 to 40 percent
Silt: 50 to 74 percent
Clay: 6 to 12 percent
Organic matter: 2 to 6 percent
Fluidity class: nonfluid
Reaction class: slightly acid to neutral (pH 6.1 to 7.3)

2Cseg1 horizon:
Hue: 2.5Y or N
Value: 2.5 to 4 moist, 4 to 6 dry
Chroma: 1 or 2
Texture: silt loam
Sand: 20 to 42 percent
Silt: 50 to 74 percent
Clay : 8 to 16 percent
Organic matter: 0.4 to 2 percent
Fluidity class: nonfluid to slightly fluid
Reaction class: slightly acid to neutral (pH 6.1 to 7.3)

2Cseg2 horizon:
Hue: 2.5Y, 10Y, or N
Value: 2.5 to 4 moist, 4 to 6 dry
Chroma: 1 or 2
Texture: silt loam
Sand: 15 to 32 percent
Silt: 50 to 67 percent
Clay : 18 to 24 percent
Organic matter: 0.4 to 2 percent
Fluidity class: slightly fluid to moderately fluid
Reaction class: slightly acid to neutral (pH 6.1 to 7.3)

2Cseg3 horizon:
Hue:10Y or N
Value: 2.5 to 4 moist, 4 to 6 dry
Chroma: 1 or 2
Texture: silt loam
Sand: 15 to 34 percent
Silt: 50 to 69 percent
Clay: 16 to 22 percent
Organic matter: 0.4 to 2 percent
Fluidity class: slightly fluid or moderately fluid
Reaction class: moderately acid to slightly acid (pH 5.6 to 6.5)

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING:
Elevation: 0 to 25 meters (0 to 82 feet)
Parent material: loamy alluvium derived from metamorphic and sedimentary rock over loamy estuarine deposits
Landform: depressions on delta plains, abandoned channels on delta plains
Slopes: 0 to 1 percent
Mean annual precipitation: 300 to 400 mm (12 to 16 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 Akulik River and Ryanlake soils.
Akulik River soils lack ponding, lack sulfidic materials, have a cambic horizon, have a coarse-loamy particle size class, have a gelic soil temperature regime, have occasional, brief flooding, and occur on talfs of delta plains
Ryanlake soils lack ponding, have permafrost, have cryoturbation, have a thick organic surface, have a gelic soil temperature regime, have an isotic mineralogy class, have a clay range of 2 to 10 percent, have occasional, brief flooding, and occur on treads of terraces

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class: very poorly drained
Saturation during normal years--saturated throughout the profile during the growing season
Saturated Hydraulic Conductivity: moderately high in the Ag, 2Cseg1, 2Cseg2, and 2Cseg3 horizons
Permeability: moderate in the Ag, 2Cseg1, 2Cseg2, and 2Cseg3 horizons
Runoff: negligible
Flooding frequency and duration: frequent and long
Ponding frequency and duration: frequent and very long

USE AND VEGETATION:
Use: wildlife habitat, recreation, and subsistence
Native vegetation: Ramensk's sedge, Lyngbye's sedge, American dunegrass, manyflower sedge, pendantgrass, Pacfic silverweed, western dock, lesser saltmarsh sedge, Alaska bog willow, Fisher's tundragrass, tall cottongrass, red fescue

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: 25 to 100 cm (10 to 39 in)

Ochric epipedon: 0 to 3 cm (0 to 1 in) (Ag horizon)

Sulfidic materials: 3 to 19 cm (1 to 8 in) (2Cseg1 horizon)

Reduced matrix: 3 to 200cm (1 to 79 in) (2Cseg1, 2Cseg2, 2Cseg3 horizons)

Lithologic discontinuity: 3 to 200 cm (1 to 79 in) (2Cseg1, 2Cseg2, 2Cseg3 horizons)

n value greater than 0.7: 19 to 200 cm (8 to 79 in) (2Cseg2, 2Cseg3 horizons)

Aquic conditions: 0 to 200 cm (0 to 79 in) (Ag, 2Cseg1, 2Cseg2, 2Cseg3 horizons)

ADDITIONAL DATA:

User pedon ID: 2023AK180342

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National Cooperative Soil Survey
U.S.A.