LOCATION KLASI AK
Established Series
Rev. MHC/JPM
08/2024
KLASI SERIES
The Klasi series consists of poorly and very poorly drained soils formed in a thick organic mat overlying clayey lacustrine deposits. Permafrost occurs at a depth of 4 to 38
inches. Klasi soils are on broad lacustrine terraces. Slopes range from 0 to 12 percent. Mean annual temperature is about 26 degrees F. and the average annual precipitation is about 16 inches.
TAXONOMIC CLASS: Fine, mixed, superactive, nonacid, subgelic Typic Histoturbels
TYPICAL PEDON: Klasi peat - on a 2 percent slope under black spruce forest at 2050 feet (625 meters) elevation. (All colors are for moist soil)
Oi=0 to 5 inches; very dusky red (2.5YR 2.5/2) peat; slightly decomposed moss and root fibers; abrupt irregular boundary. (5 to 8 inches thick)
Oe--5 inches to 8; very dark brown (10YR 2/2) mucky peat; partially decomposed moss and root fibers; abrupt irregular boundary. (3 to 6 inches thick)
A--8 to 10 inches; very dark grayish brown (10YR 3/2) silty clay loam; strong very fine granular structure; friable, very sticky and very plastic; many very fine and fine roots; neutral (pH 6.6); clear irregular boundary. (0 to 3 inches thick)
C1--10 to 24 inches; dark grayish (2.5YR 4/2) silty clay; strong fine subangular blocky structure; firm, very sticky and very plastic; 5 percent cobble and 5 percent gravel; neutral (pH 6.8); gradual wavy boundary. (4 to 16 inches thick)
C2--24 to 31 inches; dark grayish brown (2.5Y 4/2) clay; strong fine subangular blocky structure; firm, very sticky and very plastic; 5 percent cobble and 5 percent gravel; mildly alkaline (pH 7.4); abrupt wavy boundary. (0 to 10 inches thick)
Cf--31 to 41 inches (58 to 84 centimeters); dark grayish brown (5Y 4/2) moist silty clay; mildly alkaline (pH 7.4); frozen on July 31, 1992.
TYPE LOCATION: Copper River Basin, Alaska; about 8 miles northwest of Sourdough; the SE1/4 of the SW1/4 of section 19, T.10N., R.3W., Copper River Meridian.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is less than 32 degrees F. The mat of organic material ranges from 8 to 16 inches thick. Depth to permafrost ranges from 4 to 38 inches below the surface of the mineral soil two months after the summer solstice. There is more than 35 percent clay by weighted average in the particle size control section. Coarse fragment content ranges from 0 to 20 percent. The reaction ranges from slightly acid to mildly alkaline.
The A or AC horizon has moist hue of 10YR or 2.5Y; moist value of 2 or 3; and moist chroma of 1 through 3. Texture is silty clay loam, silty clay, or clay.
The C horizons have moist hue of 2.5Y or 5Y; moist value of 4 or 5, and moist chroma of 1 or 2. Textures include silty clay and clay. Coarse fragment content ranges from 0 to 20 percent with 0 to 10 percent cobble and 0 to 15 percent gravel. A lag concentration of coarse fragments is
common along the upper boundary of the horizon.
Ice content in the Cf horizon is variable and includes disseminated or segregated ice crystals or thin seams.
COMPETING SERIES: This is the
Klawasi series. Klawasi soils have a thin mantle of silty loess over clayey lacustrine deposits.
GEOGRAPHIC SETTING: Klasi soils formed in a thick organic mat overlying lacustrine sediments on lacustrine terraces. Slopes range from 0 to 12 percent.
The climate is subarctic continental with long, cold winters and short, warm summers. Mean annual precipitation ranges from 14 to 18 inches. The mean annual temperature ranges from 23 to 27 degrees F.
DRAINAGE AND PERMEABILITY: Klasi soils are poorly or very poorly drained; runoff is very slow; permeability is moderate above the impermeable permafrost. The profile typically is saturated with water in the A horizon, but free water often occurs within the organic surface
horizon in depressional areas. Altered drainage occurs where the insulating organic mat is destroyed by fire or clearing. Loss of the organic mat results in lowering of the permafrost level with subsequent lowering of the water table.
USE AND VEGETATION: Most areas of Klasi soils are in native vegetation of white spruce and black spruce forest. The successional state of the vegetation in a given area is closely related to the fire history. This soil is used primarily for wildlife habitat.
DISTRIBUTION AND EXTENT: Copper River Basin, Alaska. The series is extensive.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: WASILLA, ALASKA
SERIES ESTABLISHED: Gulkana River Area, Alaska. 1999
REMARKS: Diagnostic horizons and features recognized in this pedon: are a histic epipedon from 8 inches to 0; permafrost at 23 inches, and saturated conditions 2 inches below the surface of the mineral soil; clayey particle
size class from 2 to 33 inches; pH >5.5 (1:1,H2O) in control section. Formerly classified as Histic Pergelic Cryaquepts
National Cooperative Soil Survey
U.S.A.