LOCATION CHISNA                  AK

Established Series
SDB/MJS
08/2025

CHISNA SERIES

Depth class: very deep
Drainage class: well drained
Parent material: silty loess over sandy and gravelly till
Landscape: foothills
Landform: hillslopes
Slopes: 0 to 20 percent
Mean annual precipitation: about 600 mm (24 in)
Mean annual air temperature: about -3 degrees C. (27 degrees F)
Frost-free period: 32 to 71 days

TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, nonacid, subgelic Turbic Humigelepts

TYPICAL PEDON: Chisna highly organic silt loam in ericaceous and willow scrub on a linear, linear summit on a slope of 2 percent at an elevation of 1221m (4005 ft).

A--0 to 7 cm (0.0 to 3 in); silt loam, black (5Y 2.5/2) moist; moderate coarse subangular blocky structure; slightly hard, friable, nonsticky, nonplastic; nonsmeary; common very fine and fine roots throughout; very fine irregular pores; 10 percent subrounded cobbles by volume; strongly acid (pH 5.4); clear wavy boundary (6 to 11 cm, 3 to 4 in).

Ajj--7 to 20 cm (3 to 8 in); silt loam, dark olive brown (2.5Y 3/3) moist; moderate coarse subangular blocky parts to weak fine platy structure; slightly hard, friable, nonsticky, nonplastic; nonsmeary; few very fine and fine roots throughout; very fine vesicular pores; 5 percent subrounded cobbles by volume; moderately acid (pH 5.6); clear wavy boundary (12 to 17 cm, 5 to 7 in).

Ejj--20 to 28 cm (8 to 11 in); silt loam, olive brown (2.5Y 4/4) moist; weak coarse platy parts to weak fine granular structure; soft, very friable, slightly sticky, slightly plastic; nonsmeary; few very fine and fine roots throughout; fine irregular pores; 5 percent subrounded cobbles by volume; moderately acid (pH 5.8); clear wavy boundary (7 to 12 cm, 3 to 5 in).

2C1--28 to 49 cm (11 to 19 in); cobbly sandy loam, olive brown (2.5Y 4/3) moist; weak medium granular structure; soft, very friable, slightly sticky, slightly plastic; nonsmeary; few very fine roots throughout; fine irregular pores; 25 percent subrounded cobbles by volume; moderately acid (pH 6.0); clear wavy boundary (16 to 22 cm, 6 to 9 in).

2C2--49 to 150 cm (19 to 59 in); gravelly sandy loam, olive gray (5Y 4/2) moist; soft, very friable, slightly sticky, slightly plastic; nonsmeary; fine irregular pores; 15 percent subrounded gravel by volume; slightly acid (pH 6.2); clear wavy boundary (88 to 109 cm, 35 to 43 in).

TYPE LOCATION: North Copper River Soil Survey Area, Alaska; latitude 63.08731, longitude -145.37425, UTM 6865681.19 north, and UTM 481346.19 east, zone 6, Datum WGS84.

RANGE IN CHARACTERISTICS:

Soil moisture regime: udic
Soil temperature regime: cryic
Mean annual soil temperature: -2 to 2 degrees C. (28 to 36 degrees F)
Thickness of umbric epipedon: 19 to 32 cm (7 to 13 in)
Depth to lithologic discontinuity: 25 to 40 cm (10 to 16 in)

A horizon:
Hue: 10YR or 2.5Y
Value: 2 to 3
Chroma: 1 to 3
Texture: silt loam, gravelly silt loam, cobbly silt loam
Sand: 27 to 43 percent
Silt: 53 to 69 percent
Clay: 4 to 9 percent
Rock fragments: 4 to 19 percent
Cobbles: 4 to 19 percent
Organic matter: 4 to 6 percent
Reaction class: strongly acid to moderately acid (pH 5.1 to 6)

Ejj horizon:
Hue: 10YR or 2.5Y
Value: 4 to 5
Chroma: 4 to 5
Texture: silt loam, cobbly silt loam
Sand: 27 to 38 percent
Silt: 52 to 68 percent
Clay: 5 to 11 percent
Rock fragments: 4 to 23 percent
Cobbles: 4 to 23 percent
Organic matter: 0.8 to 3 percent
Reaction class: strongly acid to moderately acid (pH 5.1 to 6)

C horizon:
Hue: 2.5Y or 5Y
Value: 4 to 5
Chroma: 2 to 3
Texture: sandy loam, gravelly sandy loam, cobbly sandy loam
Sand: 55 to 76 percent
Silt: 7 to 36 percent
Clay: 9 to 17 percent
Rock fragments: 12 to 27 percent
Gravels: 12 to 24 percent
Cobbles: 16 to 27 percent
Organic matter: 0 to 0.8 percent
Reaction class: moderately acid to slightly acid (pH 5.6 to 6.5)

Some pedons have Bw horizon between the A and C horizons. The B horizons have a Sandy loam or gravelly sandy loam texture, have a hue of 10YR or 2.5Y, value of 3 to 4, and a chroma of 2 or 3.

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING:
Elevation: 400 to 1400 meters (1310 to 4595 feet)
Parent material: silty loess over sandy and gravelly till
Landform: moraines, hillslopes
Slopes: 0 to 20 percent
Mean annual precipitation: 400 to 800 mm (16 to 31 in)
Mean annual air temperature: -4 to -2 degrees C. (25 to 28 degrees F)
Frost free period: 32 to 71 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ahtell and Chelina series
Ahtell soils are well drained, lack permafrost, have folistic and umbric epipedons, and occur on hill tops, and hillside positions.
Chelina soils are well drained, lack an umbric epipedon, and occur on lacustrine terraces.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class: well drained
Saturated Hydraulic Conductivity: moderately high in the A and E horizons, moderately high to high in the C horizon.
Permeability: moderate in the A and E horizons, moderate to moderately rapid in the C horizons.
Runoff: low

USE AND VEGETATION:
Use: wildlife habitat, recreation, and subsistence
Native vegetation: black crowberry, white artic mountain heather, netleaf willow, reindeer lichen.

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:25 to 100 cm (10 to 39 in)

Umbric epipedon: 0 to 20 cm (0 to 8 in) (A horizons)

Gelic materials horizon: 7 to 40 cm (3 to 16 in) (Ajj and Ejj horizons)

Lithologic discontinuity: 28 to 150 cm (11 to 59 in) (2C horizons)

ADDITIONAL DATA:

User pedon Id: 2023AK261608

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National Cooperative Soil Survey
U.S.A.