LOCATION IKSGIZA AK
Established Series
Rev. DKS/JPM
05/2022
IKSGIZA SERIES
The Iksgiza series consists of poorly drained soils formed in silty micaceous loess and silty colluvium overlying eolian sand. Permafrost is in the loess layer within 15 to 40 inches of the soil surface. Iksgiza soils are on nearly level to steep, dune covered alluvial plains. Slopes range from 0 to 30 percent. Mean annual temperature is about 26 degrees F., and the average annual precipitation is about 15 inches.
TAXONOMIC CLASS:
TYPICAL PEDON: Iksgiza peat - under black spruce, shrub, and moss vegetation at 550 feet elevation. (All colors are for moist soil)
Oi-- 0 to 7 inches; very dark brown (10YR 2/2) slightly decomposed peat; many fine and common medium roots; strongly acid (pH 5.2); abrupt smooth boundary. (2 to 10 inches thick)
Oe--7 to 10 inches; dark brown (7.5YR 3/2) moderately decomposed peat; many fine and few medium roots; strongly acid (pH 5.2); abrupt smooth boundary. (3 to 12 inches thick)
Bg--10 to 18 inches; dark grayish brown (2.5Y 4/2) silt loam; weak medium subangular blocky structure; nonsticky and nonplastic; many medium distinct olive brown (2.5Y 4/4) mottles; common very fine to medium roots; strongly acid (pH 5.2); abrupt smooth boundary. (4 to 20 inches thick)
Cf1--18 to 38 inches; light olive brown (2.5Y 5/4) permanently frozen silt loam; massive; very hard; moderately acid (pH 5.8); clear smooth boundary. (0 to 30 inches thick)
2Cf2--38 to 60 inches; pale olive (5Y 6/3) frozen fine sand; massive; very hard; moderately acid (pH 5.8).
TYPE LOCATION: Kantishna Area, Alaska; NW 1/4 of the SE 1/4 of section 6, T. 2S., R. 14W., Fairbanks Meridian.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is less than 32 degrees F. The mat of organic material consists of partially decomposed moss and roots 6 to 16 inches thick. Depth to permafrost ranges from 15 to 40 inches below the soil surface. Thickness of the silty mantle and depth to the contrasting sand material is 10 to 40 inches. The control section contains substantial mica. Reaction is very strongly or strongly acid in the organic mat and strongly acid to neutral in the lower horizons.
The A horizon, when present, has hue from 5YR to 10YR; value moist of 2 or 3; and chroma moist from 1 to 3. Texture is mucky silt loam or silt loam.
The Bg horizon has hue from 10YR to 5Y; value moist from 3 to 5; and chroma moist from 1 to 4. Texture is silt loam or very fine sandy loam, and may include lenses of fine sandy loam.
The C or Cf horizon, when present, has hue from 10YR to 5Y; value moist from 3 to 5; and chroma moist from 2 to 4. Texture is silt loam or very fine sandy loam, and may include lenses of fine sandy loam. Thin ice lenses are usually present.
The 2Cf horizon has hue from 2.5Y to 5Y; value moist from 3 to 6; and chroma moist from 2 to 4. Texture is fine sand, loamy fine sand, sand, or loamy sand.
COMPETING SERIES: These are the Deborah (T),
Kuslina,
Mendeltna,
Saulich,
Tolsona, and
Umiat (T) series. Deborah and Saulich soils have less than 15 percent fine sand or coarser in the control section. Kuslina soils lack micaceous influence. Mendeltna soils have greater than 18 percent clay in the control section. Tolsona soils have no strata and lack micaceous influence. Umiat soils have weathered bedrock within the control section.
GEOGRAPHIC SETTING: Iksgiza soils formed in a thick organic mat over silty loess that is underlain by eolian sand. Iksgiza soils are on nearly level to steep concave areas on dune mantled alluvial plains. Slopes range from 0 to 30 percent. The climate is subartic continental with long, cold winters and short, warm summers. Mean annual precipitation is about 15 inches and includes mean annual snowfall of about 60 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the
Nenana and Zitzian soils. Nenana and
Zitziana soils generally occur upslope from Iksgiza soils, are well drained and lack permafrost.
DRAINAGE AND PERMEABILITY: Poorly drained. Runoff is ponded to medium. Permeability is moderate above the permafrost. Altered drainage occurs where the insulating organic layer is destroyed by fire or mechanical clearing. Loss of the organic mat results in lowering of the permafros
level with subsequent lowering of the water table. The texture an corresponding permeability of the thawed underlying material is highly variable.
USE AND VEGETATION: Native vegetation consists of black spruce, willows, mosses and shrubs. Used for wildlife habitat and recreation.
DISTRIBUTION AND EXTENT: Central interior Alaska. The series is of moderate extent.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: WASILLA, ALASKA
SERIES ESTABLISHED: Kantishna Area, Alaska, 1998.
REMARKS: Diagnostic horizons and features recognized in this profile include: A histic epipedon; permafrost at 18 inches with saturated conditions above; weighted average particle size of coarse-loamy from 10 to 40 inches.
National Cooperative Soil Survey
U.S.A.