LOCATION CHUIT AK
Established Series
Rev. KMO-JPM-LEE
02/2022
CHUIT SERIES
The Chuit series consists of very deep, well drained soils formed in a mantle of ash-influenced loess overlying glacial till. Chuit soils are on mountain sideslopes influenced by glaciation. Slopes range from 2 to 45 percent. The mean annual temperature is about 32 degrees F. The average annual precipitation is about 26 inches.
TAXONOMIC CLASS: Medial over loamy, mixed, superactive Andic Humicryods
TYPICAL PEDON: Chuit silt loam - on a 4 percent northeast facing slope under alpine tundra vegetation. (All colors are for moist soil)
Oi--3 inches to 0; mat of slightly decomposed litter from alpine tundra vegetation; abrupt smooth boundary. (0 to 4 inches thick)
A--0 to 1 inch; dark brown (10YR 3/3) silt loam; weak fine granular structure; very friable; many fine roots; strongly acid; abrupt broken boundary. (0 to 5 inches thick)
Bhs1--1 to 4 inches; black (10YR 2/1) silt loam; weak fine subangular blocky structure; very friable, slightly smeary; few fine roots; pockets of dark brown (10YR 3/3); strongly acid; clear broken boundary.
Bhs2--4 to 7 inches; very dark brown (10YR 2/2) silt loam; weak fine granular structure; very friable, slightly smeary; few fine roots; pockets of black (10YR 2/1) due to frost churning; strongly acid; clear broken boundary.
Bhs3--7 to 9 inches; very dark brown (10YR 2/2) silt loam; weak fine subangular blocky structure; very friable, slightly smeary; few fine roots; pockets of dark brown (10YR 3/3) and yellowish brown (10YR 5/4) due to frost churning; strongly acid; clear broken boundary. (combined C horizons: 4 to 9 inches thick)
Bs--9 to 17 inches; yellowish brown (10YR 5/4) silt loam; weak fine subangular blocky structure; very friable; few fine roots; pockets of dark brown (10YR 2/2) due to frost churning; strongly acid; clear wavy boundary. (0 to 10 inches thick)
Ab--17 to 20 inches; dark brown (7.5YR 3/2) silt loam; weak fine subangular blocky structure; very friable; strongly acid; clear wavy boundary. (0 to 8 inches thick)
Bsb--20 to 24 inches; dark brown (10YR 3/3) silt loam; weak fine subangular blocky structure; very friable, slightly smeary; 1/4 inch thick yellowish brown (10YR 5/4) ash layer; strongly acid; clear wavy boundary. (3 to 15 inches thick)
C1--24 to 33 inches; dark brown (10YR 3/3) silt loam; massive; very friable; strongly acid; clear wavy boundary. (0 to 9 inches thick)
2C2--33 to 60 inches; yellowish brown (10YR 5/8) gravelly silt loam; firm; 15 percent gravel; strongly acid.
TYPE LOCATION: Yentna Area, Alaska, in the NW 1/4 of the SW 1/4 of section 25, T.13N., R.14W., Seward Meridian.
RANGE IN CHARACTERISTICS: The pedons have a bisequal sola. The combined sola ranges from 14 to 28 inches thick. The loess mantle ranges from 14 to 38 inches thick over the firm, glacial till substratum. The exchange complex of the sola is dominated by amorphous material. The sola is churned and mixed by frost action. Small pockets of ash occur in the sola of some pedons. The upper 4 inches of the spodic horizons have more than 6 percent organic carbon. Reaction throughout the profile is strongly or very strongly acid.
The A horizon has hue from 5YR to 10YR; value moist from 2 to 4; and chroma moist from 1 to 3. This horizon has been heavily frost churned in many pedons.
The Bhs horizons have hue from 5YR to 10YR; value moist of 2 or 3; and chroma moist of 1 or 2. Texture is silt loam or very fine sandy loam.
The B horizons have hue from 5YR to 10YR; value moist from 3 to 5; and chroma moist from 3 to 8. The buried B horizons are similar in color and texture.
The C horizon has hue of 7.5YR or 10YR; value moist from 3 to 5; and chroma moist from 2 to 8. This horizon is absent in some pedons.
The 2C horizon is massive, firm, loam or silt loam. Coarse fragment content ranges from 5 to 35 percent with 5 to 25 percent gravel and 0 to 10 percent cobble.
COMPETING SERIES: This is the
Puntilla series in the same family, and the
Talkeetna series in the same subgroup. Puntilla soils are not churned and mixed by frost. Talkeetna soils have more than 35 percent coarse fragments in the lower part of the control section.
GEOGRAPHIC SETTING: The Chuit soils are on mountain sideslopes that have been covered with glacial till. Slopes range from 2 to 45 percent. The soils formed in an ash-influenced loess mantle overlying firm glacial till. The surface is characterized by hummocks caused by frost action. The mean annual temperature ranges from 30 to 34 degrees F. The average annual precipitation ranges from 20 to 32 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the competing
Puntilla soils and the
Nakochna soils. Nakochna soils are on similar landscapes and are less than 20 inches deep over bedrock.
DRAINAGE AND PERMEABILITY: Well drained. Slow to rapid runoff. Moderate permeability in the loess mantle and moderately slow permeability in the underlying material.
USE AND VEGETATION: The native vegetation is characteristic of alpine tundra: mainly ericaceous shrubs, dwarf birch, prostate willows, mosses, and lichens. Use is restricted by the short growing season.
DISTRIBUTION AND EXTENT: South-central Alaska. The series is of minor extent.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: WASILLA, ALASKA
SERIES ESTABLISHED: Yentna Area, Alaska, 1986.
REMARKS: Diagnostic features and horizons recognized in this profile include: spodic horizons from 1 to 17 inches; cryic temperature regime; assumed greater than 6 percent organic carbon in the upper 4 inches of the spodic horizon; exchange complex dominated by amorphous material from 10 to 33 inches; loamy particle size from 33 to 40 inches.
National Cooperative Soil Survey
U.S.A.