LOCATION KIOKLUK                 AK

Tentative Series
Rev. MHC-JPM
02/2022

KIOKLUK SERIES

The Kiokluk series consists of very deep, well drained soils formed in loess deposits overlying coarse textured glaciofluvial sediments. Kiokluk soils are on stream terraces, hillslopes and outwash plains. Slopes range from 0 to 45 percent. Mean annual temperature is about 35 degrees F. and the average annual precipitation is about 17 inches.

TAXONOMIC CLASS: Coarse-silty, mixed, superactive, nonacid Typic Cryorthents

TYPICAL PEDON: Kiokluk silt loam - on a 2 percent slope under birch forest and bluejoint reedgrass vegetation at 150 feet elevation. (All colors are for moist soil)

Oe--2 inches to 0 ; partially decomposed forest and grass litter. (1 to 3 inches thick)

A--0 to 3 inches; dark brown (10YR 3/3) silt loam; weak fine granular structure; very friable, nonsticky and nonplastic; many roots of all sizes; medium acid (pH 5.8); clear smooth boundary. (2 to 5 inches thick)

AC--3 to 10 inches; stratified dark brown (10YR 3/3) and dark grayish brown (10YR 4/2) silt loam; weak fine granular structure; very friable, nonsticky and nonplastic; many very fine, fine and medium roots; medium acid (pH 6.0); gradual smooth boundary. (0 to 10 inches thick)

ACb-10 to 19 inches; dark grayish brown (10YR 4/2) and brown (10YR 4/3) silt loam; weak thin platy structure; very friable, nonsticky and nonplastic; few fine faint dark yellowish brown (10YR 4/4) mottles; common very fine and fine roots; slightly acid (pH 6.4); gradual irregular boundary. (4 to 15 inches thick)

Bw/Cb--19 to 31 inches; stratified dark grayish brown (10YR 4/2) and dark gray (10YR 4/1) silt loam; weak medium subangular blocky structure; very friable, nonsticky and nonplastic; common medium faint dark yellowish brown (10YR 4/4) mottles; common very fine and fine roots; slightly acid (pH 6.4); gradual irregular boundary. (10 to 26 inches thick)

Bwb--31 to 50 inches; dark yellowish brown (10YR 4/4) silt loam; moderate medium subangular blocky structure; very friable, nonsticky and nonplastic; few fine faint dark grayish brown (10YR 4/2) mottles; few very fine roots; neutral (pH 6.6); clear smooth boundary. (12 to 25 inches thick)

2BC--50 to 53 inches; brown (10YR 4/3) very gravelly loamy coarse sand; weak medium subangular structure; very friable, nonsticky and nonplastic; 30 percent rounded gravel and 10 percent rounded cobble; few very fine roots; neutral (pH 6.6); clear wavy boundary. (0 to 8 inches thick)

2C--53 to 60 inches; variegated very gravelly coarse sand; single grain; loose, nonsticky and nonplastic; 45 percent rounded gravel and 10 percent rounded cobble; neutral (pH 6.8).

TYPE LOCATION: Matanuska-Susitna Area, Alaska; NW 1/4, SE 1/4, Section 32, T. 18 N., R 2 E., Seward Meridian.

RANGE IN CHARACTERISTICS: Depth to sand and gravel ranges from 40 to over 60 inches. Texture of the loess mantle is silt loam with less than 18 percent clay and less than 15 percent fine sand or coarser. Reaction ranges from moderately acid to neutral in the loess cap and slightly acid or neutral in the substratum.

The A horizons have moist hue from 10YR through 2.5Y; value moist from 2 through 4; and chroma moist of 2 or 3. Occasional thin strata of darker colors (buried O horizons and charcoal) occur throughout these horizons. Texture is silt loam or very fine sandy loam with occasional strata of fine sand.

The buried B/C horizons have two dominant color groups. The B portion has hue of 7.5YR or 10YR; chroma moist from 4 through 6. The C portion has has hue from 10YR through 5Y; chroma moist of 1 or 2. Occasional thin strata of darker colors (buried O horizons and charcoal) occur throughout these horizons. Texture is silt loam or very fine sandy loam.

The Bwb horizon has hue of 7.5YR or 10YR; chroma moist from 4 to 6; Texture is silt loam or very fine sandy loam.

The BC horizon, when present, has hue of 10YR or 2.5YR; value moist of 3 or 4; chroma moist of 3 or 4. Texture is sandy loam, loamy sand, or loamy coarse sand. Coarse fragments range from 20 to 45 percent and include rounded gravel and cobble.

The 2C horizons have variegated colors. Textures include sand, coarse sand and loamy coarse sand. Rock fragments range from 40 to 60 percent include rounded gravel, cobble and few stones.

COMPETING SERIES: This is the Jim series. Jim soils overlay bedrock within 20 to 40 inches of the surface.

GEOGRAPHIC SETTING: The Kiokluk soils are on broad terraces bordering glacial rivers and on adjacent low hills and outwash plains. They formed in a loess mantle overlying glaciofluvial deposits of sand and gravel. Kiokluk soils receive an annual increment of fresh loess. The loess consists of glacial flour from active glacial outwash plains. The climate is transitional maritime-continental. Mean annual temperature is 35 degrees F. and mean annual precipitation is 17 inches.

DRAINAGE AND PERMEABILITY: Well drained. Slow to rapid runoff. Moderate permeability in the loess mantle and rapid in the underlying sand and gravel.

USE AND VEGETATION: Used for cropland, pasture, and wildlife habitat. The native vegetation includes white spruce and paper birch.

DISTRIBUTION AND EXTENT: Southcentral Alaska. The series is of moderate extent.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: WASILLA, ALASKA

SERIES PROPOSED: Matanuska-Susitna Area, 1989.

REMARKS: Diagnostic horizons and features recognized in this profile include: no diagnostic horizons within 50 cm.; cryic temperature regime; weighted average of coarse silty particle size from 0 to 50 inches; pH greater than 5.5 (H20,1:1) throughout the control section.

---

National Cooperative Soil Survey
U.S.A.