LOCATION RICEPEAK                AK

Established Series
SDB/MJS
08/2025

RICEPEAK SERIES

Depth class: shallow to permafrost
Drainage class: poorly drained
Parent material: mossy organic material over sandy alluvium
Landscape: mountains
Landform: till plains and flats
Slope: 0 to 2 percent
Mean annual precipitation: about 320 mm (13 in)
Mean annual air temperature: about -4 degrees C (25 F)
Frost-free period: 70 to 90 days

TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, nonacid, subgelic Typic Historthels

TYPICAL PEDON: Ricepeak peat in a blueberry and moss community on a till plain, on a slope of 2 percent at an elevation of 602m (1975 ft)

Oi--0 to 21 cm (0 to 8 in); peat, very dark brown (10YR 2/2) broken face moist; low excavation difficulty; many very fine, fine, common medium, and very few coarse roots throughout; common very fine and fine tubular pores; slightly acid (pH 6.5); gradual wavy boundary (20 to 30cm, 8 to 12 in)

Cg--21 to 37 cm (8 to 15 in); sandy loam, dark gray (2.5Y 4/1) broken face moist; massive; slightly hard, friable, slightly sticky, slightly plastic; nonsmeary; low excavation difficulty; many very fine, fine, and common medium roots throughout; few very fine and fine tubular pores; 5 percent irregular brownish yellow (10YR 6/6), moist, iron depletions throughout; 10 percent gravels by volume; neutral (pH 6.9); abrupt wavy boundary. (15 to 20 cm, 6 to 8 in)

Cgf--37 to 150 cm (15 to 59 in); sandy loam, gray (2.5Y 5/1) broken face moist; massive; slightly hard, friable, noncoherent, slightly sticky, slightly plastic; nonsmeary; high excavation difficulty; few very fine and fine roots throughout; few very fine and fine tubular pores; 5 percent irregular iron depletions throughout; 5 percent gravels by volume; neutral (pH 6.9) (100 to 115 cm, 39 to 45 in)

TYPE LOCATION: North Copper River Soil Survey Area, Alaska; latitude 61.68445, longitude -145.21243, UTM 6840327.15 north and UTM 594586.38 east, zone 6, Datum WGS84.

RANGE IN CHARACTERISTICS:

Soil moisture regime: aquic
Soil temperature regime: gelic
Mean annual soil temperature: -4 to 1 degrees C. (25 to 34 degrees F)
Thickness of histic epipedon: 20 to 30 cm (8 to 12 in)
Depth to redoximorphic concentrations: 20 to 30 cm (8 to 12 in)
Depth to redoximorphic depletions: 20 to 30 cm (8 to 12 in)
Depth to permafrost: 35 to 50 cm (14 to 20 in)

Oi horizon:
Hue: 7.5YR or 10YR
Value: 2 to 3
Chroma: 1 to 3
Texture: peat, mucky peat
Organic matter: 60 to 90 percent
Reaction class: moderately acid to neutral (pH 6.0 to 6.8)

Cg, Cgf horizon:
Hue: 2.5Y or 5Y
Value: 4 to 5
Chroma: 1 to 2
Texture: sandy loam, gravelly sandy loam
Sand: 55 to 68 percent
Silt: 15 to 32 percent
Clay: 12 to 17 percent
Rock fragments: 8 to 16 percent gravels
Organic matter: 0.2 to 1.5 percent
Reaction class: slightly acid to neutral (pH 6.5 to 7.2)

Some pedons have an A horizon that is 1 to 20 cm (1 to 8 in) thick, with a texture of silt or silt loam, hue of 10YR or 2.5Y, value of 2 or 3, and chroma of 1 to 2.

COMPETING SERIES: These are the Coppercenter, Goldenorth, and Tseenjik soils.
Coppercenter soils have a mollic epipedon and permafrost starting below 50 cm (20 in).
Goldennorth soils are very poorly drained, have a loess cap over gravely till, and occur on hillslopes in valleys.
Tseenjik soils have permafrost starting below 50 cm (20 in) and occur on floodplains at elevations between 90 and 220 m (295 and 720 ft).

GEOGRAPHIC SETTING:
Elevation: 400 to 800 meters (1310 to 2625 feet)
Parent material: mossy organic material over sandy alluvium
Landform: till plains, flats
Slopes: 0 to 2 percent
Mean annual precipitation: 300 to 1400 mm (12 to 55 in)
Mean annual air temperature: -5 to -1 degrees C. (23 to 30 degrees F)
Frost-free period: 60 to 103 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ganhona, Haleycreek, Hundell, and Rocklake soils.
Ganhona soils are well drained, has stratified very fine sandy loam to silt loam surface texture, and occur on river valleys, flood plains, and lacustrine terraces in mountains.
Haleycreek soils are well drained with a cobbly sandy loam surface texture, it has a mollic epipedon, lacks a lithic contact, and occur on hillslopes of mountains and river valleys.
Hundell soils are moderately well drained, with a silt loam surface texture, and occur on flats and bluffs in till plains and outwash plains.
Rocklake soils are shallow to bedrock, lack permafrost, and occur on ridge lines and escarpments.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class: poorly drained
Saturated Hydraulic Conductivity: high in the Oi and Cg horizon, low in the Cgf horizon
Permeability: moderately rapid in the Oi horizon, rapid in the Cg horizon, very slow in the Cgf horizon
Runoff: negligible

USE AND VEGETATION:
Use: wildlife habitat, recreation, and subsistence
Native vegetation: bog blueberry, black crowberry, moss

DISTRIBUTION AND EXTENT: MLRA 228 Interior Alaska mountains.
Extent: limited

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

SERIES ESTABLISHED: North Copper River Soil Survey, Alaska, 2024.

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

Particle-size control section: 46 to 121cm (18 to 48 in)

Histic epipedon: 0 to 21 cm (0 to 8 in) (Oi horizon)

Redox concentrations: 21 to 37 cm (8 to 15 in) (Cg horizon)

Permafrost: 37 to 150 cm (15 to 59 in) (Cgf horizon)

ADDITIONAL DATA:

User pedon Id: 2022AK261403

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National Cooperative Soil Survey
U.S.A.