LOCATION TONKI                   AK

Established Series
Rev. CAP
06/2025

TONKI SERIES

Depth class: very deep
Drainage class: poorly drained
Parent material: herbaceous organic material over sandy and loamy volcanic ash over medial silty volcanic ash over gravelly loamy subglacial till
Landscape: Islands
Landform: hills and plains in depressions, drainageways, and swales
Slopes: 0 to 7 percent
Mean annual precipitation: about 1250 mm (49 in)
Mean annual temperature: about 4 degrees C. (39 degrees F.)
Frost-free season: 20 to 50 days

TAXONOMIC CLASS: Medial over loamy-skeletal, amorphic over mixed, superactive, nonacid Typic Cryaquands

TYPICAL PEDON: Tonki silt loam - grass herbaceous swale at elevation 300 meters (985 feet). (All colors are for moist soil.)

Oe--0 to 11 centimeters (0 to 4 inches); black (7.5YR 2.5/1), dark gray (7.5YR 4/1), dry; mucky peat; soft, very friable, nonsticky, nonplastic; many fine, common medium, and coarse roots throughout; moderately acid (pH 5.9); abrupt smooth boundary. (5 to 18 cm, 2 to 7 in thick)

C1--11 to 34 centimeters (4 to 13 inches); 70 percent gray (10YR 6/1) and 20 percent light yellowish brown (10YR 6/4), light gray (10YR 7/1), dry; ashy fine sand; single grain; loose, nonsticky, nonplastic; common fine, medium, and coarse roots throughout; common very fine and common fine interstitial pores; 8 percent medium prominent irregular strong brown (7.5YR 4/6) masses of oxidized iron throughout; slightly acid (pH 6.2); abrupt smooth boundary. (8 to 30 cm, 3 to 12 in thick)

2A--34 to 50 centimeters (13 to 20 inches); medial silt loam; weak fine subangular blocky structure; slightly hard, friable, nonsticky, nonplastic; common very fine, fine, medium roots throughout; common very fine and common fine irregular pores; 5 percent fine distinct spherical gray (10YR 6/1) masses of reduced iron throughout; moderately acid (pH 5.8); clear smooth boundary. (8 to 25 cm, 3 to 10 in thick)

2C--50 to 80 centimeters (20 to 32 inches); medial silt loam; weak fine subangular blocky structure; slightly hard, friable, nonsticky, nonplastic; common very fine, fine, and medium roots throughout; common very fine and common fine irregular pores; 10 percent medium prominent irregular yellowish brown (10YR 5/6) masses of oxidized iron throughout; 5 percent gravel; slightly acid (pH 6.1); clear smooth boundary. (25 to 52 cm, 10 to 21 in thick)

3C--80 to 100 centimeters (32 to 79 inches); light olive gray (5Y 6/2) very gravelly sandy loam; massive; slightly hard, friable, slightly sticky, nonplastic; common fine roots throughout; common very fine and common fine irregular pores; 50 percent gravel and 5 percent cobble; slightly acid (pH 6.2).

TYPE LOCATION: Kodiak Archipelago Soil Survey Area, Alaska; Latitude 57 degrees 43 minutes 28.00 seconds and Longitude 152 degrees 34 minutes 23.00 seconds west, UTM north 6398112.55 and UTM east 525429.82, zone 5, Datum WGS84.

RANGE IN CHARACTERISTICS:

Soil moisture regime: udic
Mean annual soil temperature: 1.6 to 3.3 degrees C. (34.8 to 37.9 degrees F.)
Thickness of surface organic material: 5 to 18 cm (2 to 7 in)
Thickness of 1912 ash: 8 to 30 cm (3 to 12 in)
Depth to andic properties: 13 to 48 cm (5 to 19 in)
Depth to gravelly till: 46 to 125 cm (18 to 49 in)
Depth to aquic conditions: 0 to 25 cm ( 0 to 10 in)

Oa, Oe, Oi horizon:
Hue: 7.5YR to 10 YR
Value: 2 to 5
Chroma: 1 to 4
Texture: slightly, moderately, or highly decomposed plant material
Organic matter: 60 to 90 percent
Reaction class: extremely acid to moderately acid (pH 3.5 to 6.0)

C horizon:
Hue: 7.5YR to 10 YR
Value: 2 to 7
Chroma: 1 to 4
Texture: (ashy and glassy) sand, loamy sand, loamy fine sand, very fine sandy loam, sandy loam, or silt loam
Sand: 30 to 90 percent
Clay: 2 to 8 percent
Silt: 10 to 55 percent
Reaction class: extremely acid to moderately acid (pH 3.5 to 6.0)

2A horizon:
Hue: 7.5YR to 10YR
Value: 2 to 5
Chroma: 1 to 3
Texture: medial silt loam, silt, loam, and very fine sandy loam
Rock fragments: 0 to 14 percent
Silt: 40 to 90 percent
Clay: 2 to 14 percent
Reaction class: extremely acid to slightly acid (pH 3.5 to 6.5)

2C or 2Cg horizon:
Hue: 7.5YR to 10YR
Value: 2 to 5
Chroma: 3 to 6
Texture: (medial) silt loam, silt, loam, or very fine sandy loam, or their gravelly analogues
Silt: 40 to 90 percent
Clay: 2 to 12 percent
Rock fragments: 0 to 30 percent
Reaction class: extremely acid to slightly acid (pH 3.5 to 6.5)

3C horizon:
Hue: 7.5YR, 10YR, or 2.5Y
Value: 4 to 6
Chroma: 1 to 4
Texture: sandy loam, loamy sand, loamy coarse sand, or their gravelly analogues
Sand: 50 to 85 percent
Clay: 2 to 10 percent
Fragments: 35 to 75 percent
Reaction Class: extremely acid to slightly acid (pH 3.5 to 6.5)

COMPETING SERIES: These are the Chunila (AK) and Snowdance (AK) series.
Chunila soils lack recent ashy and glassy volcanic ash surface horizons, have mean annual precipitation less than 700 mm (28 in), and occur on similar landforms positions.
Snowdance soils lack recent ashy and glassy volcanic ash surface horizons, have mean annual precipitation less than 1000 mm (40 in), and occur on similar landforms positions.

GEOGRAPHIC SETTING:
Elevation: 5 to 400 meters (15 to 1325 feet)
Parent material: mucky peat herbaceous organic material over sandy and loamy volcanic ash over medial silty volcanic ash over gravelly loamy subglacial till
Landform: hills and plains in depressions, drainageways, and swales
Slope: 0 to 7 percent
Mean annual precipitation: 600 to 2500 mm (24 to 98 in)
Mean annual temperature: 0 to 6 degrees C. (32 to 43 degrees F.)
Frost free period: 20 to 50 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Izhut, Kizhuyak, Kodiak, Olds, Pasagshak, Sa, Salonie, and Yukuk series.
Izhut soils lack thick organic horizons, have spodic horizons, have aquic conditions greater than 25 cm (10 in), and occur on higher landform positions.
Kizhuyak soils lack thick organic horizons, have thick ashy and glassy volcanic horizons, and occur on similar landform positions.
Kodiak soils lack thick organic horizons, have spodic horizons, lack aquic conditions within 150 cm (60 in), and occur on upland landform positions.
Olds soils have histic epipedons over medial volcanic materials and skeletal till and occur in similar landform positions.
Pasagshak soils lack thick organic horizons, have sandy-skeletal control sections, lack aquic conditions less than 41 cm (16 in), and occur on slightly higher flood plains and drainageways.
Sa soils have hemic organic materials and occur on similar landform positions.
Salonie soils lack thick organic horizons, have sandy-skeletal control sections, and occur on slightly higher flood plains and drainageways.
Yukuk soils lack thick organic horizons, have andic properties, have sandy-skeletal control sections, and occur on slightly higher flood plains and drainageways.

DRAINAGE AND PERMEABILITY:
Drainage class: poorly drained
Saturated Hydraulic Conductivity: moderately high or high in the Oe horizon, moderately high to very high in the C horizon, moderately high or high in the 2A and 2C horizon, and high to very high in the 3C.
Permeability: moderate to rapid in the Oe horizon, moderate to very rapid in the C horizon, moderate to rapid in the 2A and 2C horizons, and moderate to very rapid 3C horizons.
Runoff: negligible to very low.
Ponding, duration, and depth: none to frequently with brief to very long and 0 to 30 cm (0 to 12 in).
Flooding and duration: none to frequently with brief to long.

USE AND VEGETATION:
Used as range land. The native vegetation consists of water-tolerant grasses and sedges, alder, and, in a few places, Sitka spruce.

DISTRIBUTION AND EXTENT: MLRA 220 Alexander Archipelago-
Gulf of Alaska Coast and MLRA 225 Southern Alaska Peninsula Mountains.
Extent: moderate.

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

SERIES ESTABLISHED: Kodiak Archipelago Soil Survey, Alaska, 2024.

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

Organic material: 0 to 11 cm (0 to 4 in) (mucky peat material) (Oe horizon)

1912 volcanic glass (ashy) material: 11 to 34 cm (4 to 13 in) (C horizon)

Andic properties: 34 to 80 cm (13 to 32 in) (2A, 2C horizons)

Lithological discontinuity (Glacial till): 80 to 200 cm (32 to 79 in)

Source of the volcanic ash is the 1912 eruption of Mt. Novarupta and Mt. Katmai on the Alaska Peninsula.

ADDITIONAL DATA:

User pedon Id: 09AO 01703

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National Cooperative Soil Survey
U.S.A.