LOCATION ITIRUK AK
Established Series
MPS/SAS
05/2022
ITIRUK SERIES
Landscape--hills and low mountains
Landform--saddles on ridges
Slope--0 to 15 percent
Parent material--loess over colluvium
Mean annual precipitation--about 500 mm
Mean annual air temperature--about -4 degrees C
Depth class--very deep
Drainage class--well drained
Soil moisture regime--udic
Soil temperature regime--cryic
Soil moisture subclass--typic
TAXONOMIC CLASS: Coarse-loamy, isotic Spodic Dystrocryepts
TYPICAL PEDON: Itiruk silt loam on a southeast facing convex, concave saddle on a slope of 12 percent at an elevation of 241 m (The soil was moist from 0 to 150 cm when described on August 5, 2019.)
Oe--0 to 7 cm; moderately decomposed plant material, brown (7.5YR 4/3) dry, very dark brown (7.5YR 2.5/3) moist; common very fine, fine, medium, and coarse roots; extremely acid (pH 4.3); clear smooth boundary
AE--7 to 12 cm; silt loam, brown (7.5YR 5/2) dry, dark brown (7.5YR 3/2) moist; weak medium granular structure; very friable, nonsticky, nonplastic; nonsmeary; common very fine, fine, and medium roots; very strongly acid (pH 4.6); clear smooth boundary
Bhs--12 to 28 cm; silt loam, 90 percent brown (7.5YR 5/3) and 10 percent brown (7.5YR 5/4) dry, 90 percent dark brown (7.5YR 3/3) and 10 percent dark brown (7.5YR 3/4) moist; weak medium subangular blocky structure; friable, nonsticky, nonplastic; nonsmeary; common very fine, fine, and medium roots; strongly acid (pH 5.1); abrupt irregular boundary
Bw--28 to 62 cm; silt loam, olive brown (2.5Y 4/4) dry and light yellowish brown (2.5Y 6/4) moist; 25 percent coarse dark yellowish brown (10YR 4/6) and 25 percent coarse dark grayish brown (10YR 4/2) mottles; weak thick platy structure; friable, nonsticky, nonplastic; nonsmeary; common very fine and fine roots; 5 percent subangular gravel; very strongly acid (pH 4.9); clear smooth boundary
2C--62 to 150 cm; very gravelly silt loam, pale brown (10YR 6/3) dry, brown (10YR 4/3) moist; massive; friable, nonsticky, nonplastic; nonsmeary; common very fine roots; common very fine irregular pores; 40 percent subangular gravel; very strongly acid (pH 4.9)
TYPE LOCATION: Yukon-Koyukuk Census Area, Alaska, latitude 63.0488070 longitude -160.5869423 degrees, datum WGS84 (Coordinates determined with a GPS unit)
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--0 to 3 degrees C
Soil moisture control section--dry less than 45 consecutive days in June through October (udic soil moisture regime)
Thickness ochric epipedon--5 to 15 cm
Thickness of cambic horizon--30 to 75 cm
Depth to lithologic discontinuity--42 to 100 cm
Particle Size Control Section:
*Clay--10 to 16 percent
*Total rock fragment--20 to 35 percent
*Sodium fluoride pH--8.4 to 11.6
*Ratio of 1500 kPa water to measured clay--0.6 to 6.0
Oe horizon
Thickness--2 to 8 cm
AE horizon
Value--2 to 3 moist, 4 or 5 dry
Chroma--1 or 2
Fine-earth texture--silt, silt loam
Clay--3 to 10 percent
Sand--10 to 30 percent
Organic carbon--5 to 10 percent
Ammonium oxalate Al plus 1/2 Fe--0.3 to 0.7 percent
Reaction--4.2 to 5.2
Thickness--5 to 15 cm
Bhs horizon
Hue--5YR or 7.5YR
Value--2 or 3 moist, 4 or 5 dry
Chroma--3 or 4
Clay--4 to 16 percent
Sand--20 to 35 percent
Organic carbon--5 to 10 percent
Ammonium oxalate Al plus 1/2 Fe--1 to 2 percent
Reaction--4.2 to 5.8
Thickness--5 to 20 cm
Bw horizon
Hue--7.5YR, 10YR or 2.5Y
Value--2.5 to 4 moist, 4 to 6 dry
Chroma--2 to 4
Fine-earth texture--silt loam, loam
Clay--8 to 16 percent
Sand--30 to 50 percent
Organic carbon--1 to 3 percent
Total rock fragment content--0 to 20 percent
Reaction--4.9 to 5.8
Thickness--30 to 60 cm
2C horizon
Hue--10YR or 2.5Y
Value--3 or 4 moist, 5 or 6 dry
Chroma--3 or 4
Fine-earth texture--silt loam, loam, sandy loam
Clay--8 to 16 percent
Sand--30 to 60 percent
Organic carbon--0.5 to 1 percent
Total rock fragment content--15 to 50 percent
Total gravel content--15 to 50 percent
Total cobble content--0 to 10 percent
Reaction-4.7 to 5.8
COMPETING SERIES:
*
Cranberrycreek--andic soil properties in A and Bhs horizons, rises on plains and hillslopes on hills, slope range is from 0 to 18 percent
*
Okstukuk--andic soil properties in A/E and Bhs horizons, talfs and rise on plains, slope range is from 0 to 5 percent
*
Leal--texture in A horizon ranges to loam, clay in PSCS ranges to 18 percent, moist value in A horizon ranges to 6, no Bhs horizon present; mountain sideslopes and glacial moraines, slope range is from 2 to 40 percent
GEOGRAPHIC SETTING:
*Elevation--50 to 600 m
*Climate--warm, moist summers; cold, dry winters
*Mean annual precipitation--410 to 555 mm
*Mean annual air temperature-- -5 to -1 degrees C
*Frost-free period--45 to 80 days
GEOGRAPHICALLY ASSOCIATED SOILS:
*
Chiroskey--umbric epipedon, loamy-skeletal particle-size class, andic soil properties in A horizon, mountain slopes and hillslopes
*
Oliverhill, swe--shallow to paralithic contact, mixed mineralogy, loamy-skeletal particle-size class, mountainslopes
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
*Drainage class--well drained
*Saturation during normal years--none
*Saturated hydraulic conductivity (Ksat)--very high in the surface organic layer, high to moderately high throughout the rest of the profile
USE AND VEGETATION:
Use--wildlife habitat, recreation, subsistence
Potential native vegetation--quaking aspen, white spruce, Bebb willow, Kenai birch, Siberian alder, dwarf birch, marsh Labrador tea, bog blueberry, beaverd spirea, Schreber's big red stem moss, polytrichum moss, Moss, greygreen reindeer lichen, stiff clubmoss, splendid feather moss, black spruce, bluejoint, tealeaf willow, bunchberry dogwood, arctic starflower, spreading woodfern, juniper polytrichum moss, abietinella moss
DISTRIBUTION AND EXTENT: Yukon-Kuskokwim Highlands, Alaska; MLRA 230; small extent
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: WASILLA, ALASKA
SERIES ESTABLISHED: Nulato Hills BLM area, Nome Census Area, Alaska; 2021
REMARKS:
Diagnostic horizons and features recognized in this pedon
*Particle-size control section--zone from 32 to 107 cm
*Ochric epipedon--zone from 0 to 12 cm
*Zone of illuvial accumulation of sesquioxides and organic matter--12 to 28 cm
*Cambic horizon--zone from 12 to 62 cm
*Lithological discontinuity--zone from 62 to 150 cm
National Cooperative Soil Survey
U.S.A.