LOCATION OKSTUKUK AK
Established Series
SAS/MPR
05/2022
OKSTUKUK SERIES
Landscape--plains
Landform--talfs, rises
Slope--0 to 5 percent
Parent material--volcanic ash and loess over glacial till
Mean annual precipitation--about 1100 mm
Mean annual air temperature--about 0 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: Okstukuk medial silt loam on a northeast-facing, linear and convex rise of a plain, on a slope of 5 percent at an elevation of 67 m (When described on July 17, 2007, the soil was moist to a depth of 115 cm and saturated below that depth.)
Oi--0 to 13 cm; slightly decomposed plant material; many very fine to medium and common coarse roots; very strongly acid (pH 4.8); abrupt smooth boundary
A/E--13 to 18 cm; silt loam, matrix color 80 percent brown (7.5YR 5/2) dry, dark brown (7.5YR 3/2) moist, and 20 percent gray (7.5YR 6/1) dry, dark gray (7.5YR 4/1) moist; weak fine granular structure; slightly hard, friable, nonsticky and nonplastic; many very fine and fine and common medium and coarse roots; extremely acid (pH 4.0); clear wavy boundary
Bhs--18 to 24 cm; medial silt loam, reddish brown (5YR 5/3) dry, dark reddish brown (5YR 3/3) moist; weak fine subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; common very fine and fine and few medium roots; extremely acid (pH 4.2); abrupt wavy boundary
Bw1--24 to 49 cm; silt loam, light yellowish brown (10YR 6/4) dry, dark yellowish brown (10YR 4/4) moist; weak medium subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; common very fine and fine and few medium roots; very strongly acid (pH 4.9); clear smooth boundary
Bw2--49 to 115 cm; silt loam, very pale brown (10YR 7/3) dry, brown (10YR 5/3) moist; weak medium subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; few very fine roots; strongly acid (pH 5.2); clear smooth boundary
2Cg--115 to 180 cm; silt loam, pale brown (10YR 6/3) dry, brown (10YR 4/3) moist; massive; slightly hard, friable, nonsticky and nonplastic; 10 percent medium masses of oxidized iron, reddish brown (5YR 4/4) moist, clear boundaries, and 20 percent medium iron depletions, grayish brown (2.5Y 5/2) moist, sharp boundaries; strongly acid (pH 5.3)
TYPE LOCATION: Dillingham Census Area, Alaska, about 45 km north-northeast of the city of Dillingham; latitude 59.4225000 degrees north, longitude 158.1369444 degrees west, datum WGS 84 (coordinates determined with a GPS)
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--0 to 2 degrees C
Soil moisture control section--dry less than 45 consecutive days in June through October (udic moisture regime)
Particle-size control section
*Clay content--1 to 10 percent
*Sand content--15 to 70 percent (more than 15 percent fine sand or coarser)
*Total rock fragment content--0 to 5 percent
*Sodium fluoride pH--8.4 to 11.6
*Ratio of 1500 kPa water to measured clay--0.6 to 6.0
Oi horizon
Thickness--2 to 15 cm
A/E horizon
Hue--7.5YR, 10YR
Value (A part)--2 to 3 moist, 4 or 5 dry
Value (E part)--4 or 5 moist, 6 or 7 dry
Chroma--1 or 2 moist
Fine-earth texture--silt loam, silt
Clay content--2 to 10 percent
Reaction--3.6 to 5.2
Gravel content--0 to 5 percent
Bulk density--0.45 to 0.9 g/cm3
Phosphorous retention--50 to 100 percent
Volcanic glass content--5 to 30 percent
Ammonium oxalate Al plus 1/2 Fe--0.1 to 0.4 percent
Thickness--2 to 14 cm
Bhs horizon
Hue--5YR, 7.5YR
Value--2.5 or 3 moist, 4 or 5 dry
Chroma--1 to 3 moist
Fine-earth texture--medial silt loam, medial very fine sandy loam, medial silt
Clay content--2 to 10 percent
Reaction--4.1 to 5.5
Gravel content--0 to 5 percent
Bulk density--0.45 to 0.9 g/cm3
Phosphorous retention--50 to 100 percent
Volcanic glass content--10 to 30 percent
Ammonium oxalate Al plus 1/2 Fe--0.4 to 1.0 percent
Thickness--3 to 15 cm
Bw horizons
Hue--10YR, 2.5Y
Value--3 to 5 moist, 5 to 7 dry
Chroma--2 to 4 moist
Fine-earth texture--silt, very fine sandy loam, silt loam
Clay content--2 to 10 percent
Reaction--4.6 to 5.7
Gravel content--0 to 5 percent
Sodium fluoride pH--8.4 to 11.6
Ratio of 1500 kPa water to measured clay--0.6 to 6.0
Combined thickness--50 to 150 cm
2Cg horizon
Hue--10YR, 2.5Y
Value--3 to 5 moist, 5 or 7 dry
Chroma--2 to 4 moist
Fine-earth texture--silt, silt loam, loam
Clay content--2 to 15 percent
Reaction--4.2 to 5.3
Gravel content--0 to 35 percent
COMPETING SERIES:
Leal--no aquic conditions or saturation
Cranberrycreek--no aquic conditions or saturation; cryoturbation
GEOGRAPHIC SETTING:
Elevation--0 to 300 m
Climate--warm, moist summers; cold, moist winters
Mean annual precipitation--600 to 1500 mm
Mean annual air temperature-- -3.4 to 0.9 degrees C
Frost-free period--80 to 140 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Mosquitopoint--thick organic surface; aquic conditions throughout; depressions of plains
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--well drained
Saturation in normal years--below a depth of 100 to 150 cm
Saturated hydraulic conductivity (Ksat)--moderately high or high throughout
USE AND VEGETATION:
Use--wildlife habitat, recreation, subsistence
Potential natural vegetation--white spruce, black crowberry, dwarf birch, beauverd spirea, lingonberry, bog blueberry, bluejoint grass, feathermosses
DISTRIBUTION AND EXTENT: Bristol Bay Lowlands, Alaska; MLRA 236; small extent
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: WASILLA, ALASKA
SERIES ESTABLISHED: Togiak National Wildlife Refuge-Ahklun Mountains Area, Dillingham Census Area, Alaska; 2019
REMARKS:
Diagnostic horizons and other features in this pedon
*Particle-size control section--zone from 38 to 113 cm
*Ochric epipedon
*Cambic--Bhs and Bw horizons
*Andic soil properties--Bhs horizon
*Aquic conditions--2Cg horizon
*Redoximorphic iron concentrations--2Cg horizon
*Redoximorphic iron depletions--2Cg horizon
National Cooperative Soil Survey
U.S.A.