LOCATION BENJAMINCREEK AK
Established Series
SAS/MPS
02/2022
BENJAMINCREEK SERIES
Landscape--valleys
Landform--terraces
Slope--0 to 1 percent
Parent material--herbaceous organic material over silty cyroturbate over silty alluvium
Mean annual precipitation--about 480 mm
Mean annual air temperature--about -3 degrees C
Depth class--very deep
Drainage class--moderately well drained
Soil moisture regime--udic
Soil temperature regime--cryic
Soil moisture subclass--typic
TAXONOMIC CLASS: Coarse-silty, isotic, acid Typic Cryaquepts
TYPICAL PEDON: Benjamincreek silt on a linear, linear terrace tread on a slope of 0 percent at an elevation of 92 m (The soil was moist from 0 to 55 cm, wet, non-satiated, from 55 to 65 cm, and moist from 65 to 150 cm when described on June 24, 2016.)
Oi--0 to 17 cm; slightly decomposed plant material, brown (7.5YR 5/3) dry, dark brown (7.5YR 3/3) moist; nonsticky, nonplastic; many very fine, medium, and coarse and many medium roots; extremely acid (pH 3.9); clear smooth boundary
Oe--17 to 22 cm; moderately decomposed plant material, pinkish gray (7.5YR 6/2) dry, brown (7.5YR 4/2) moist; nonsticky, nonplastic; common very fine, fine, and medium roots; extremely acid (pH 3.9); abrupt smooth boundary
Ajj--22 to 35 cm; silt, 75 percent brown (7.5YR 4/2) and 25 percent dark gray (10YR 4/1) dry, 75 percent very dark brown (7.5YR 2.5/2) and 25 percent black (10YR 2/1) moist; weak medium subangular blocky structure; friable, nonsticky, nonplastic; common very fine, fine, and medium roots; very strongly acid (pH 4.8); clear smooth boundary
Bhs--35 to 50 cm; highly organic silt loam, 60 percent dark reddish gray (5YR 4/2) and 40 percent grayish brown (10YR 5/2) dry, 60 percent dark reddish brown (5YR 2.5/2) and 40 percent very dark grayish brown (10YR 3/2) moist; weak coarse subangular blocky structure; friable, nonsticky, nonplastic; common very fine roots; 5 percent medium irregular dark yellowish brown (10YR 3/4) masses of oxidized iron with diffuse boundaries in matrix; strongly acid (pH 5.2); clear smooth boundary
C/Ajjg--50 to 85 cm; silt loam, light brownish gray (10YR 6/2) dry, dark grayish brown (10YR 4/2) moist; few medium tubular and few fine irregular pores; massive; firm, nonsticky, nonplastic; 5 percent fine irregular gray (5Y 5/1) iron depletions with clear boundaries in matrix and 5 percent fine irregular strong brown (7.5YR 4/6) masses of oxidized iron with clear boundaries in matrix; strongly acid (pH 5.3); diffuse smooth boundary
2C--85 to 150 cm; silt loam, pale brown (10YR 6/3) dry, brown (10YR 4/3) moist; massive; firm, nonsticky, nonplastic; strongly acid (pH 5.4)
TYPE LOCATION: Yukon-Koyukuk Census Area, Alaska, latitude 62.9173950 longitude -160.7477100 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
Thickness folistic epipedon--15 to 25 cm
Thickness of cambic horizon--15 to 35 cm
Depth to redoximorphic concentrations--50 to 100 cm
Depth to redoximorphic depletions with chroma of 2 or less--50 to 100 cm
Depth to depleted matrix--30 to 100 cm
Particle Size Control Section:
*Clay--5 to 17 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--10 to 20 cm
Oe horizon
Thickness--5 to 10 cm
Ajj horizon
Hue--7.5YR or 10YR
Value--2 to 3 moist, 4 or 5 dry
Chroma--1 or 2
Fine-earth texture--silt, silt loam
Clay--2 to 10 percent
Sand--5 to 20 percent
Organic carbon--2 to 8 percent
Reaction--4.5 to 5.4
Thickness--10 to 30 cm
Bhs horizon
Hue--5YR or 2.5YR
Value--2.5 or 3 moist, 4 or 5 dry
Chroma--2 or 3
Clay--2 to 12 percent
Sand--20 to 40 percent
Organic carbon--3 to 8 percent
Reaction--4.8 to 5.4
Thickness--15 to 20 cm
C/Ajjg horizon
Hue--10YR or 2.5Y
Value--4 or 5 moist, 6 or 7 dry
Chroma--2 to 5 moist
Clay--4 to 12 percent
Sand--15 to 40 percent
Organic carbon--1.5 to 3 percent
Reaction--5.0 to 6.0
Thickness--20 to 40 cm
2C horizon
Hue--10YR or 2.5Y
Value--3 to 5 moist, 5 to 7 dry
Chroma--1 to 3
Fine-earth texture--silt loam, loam
Clay--8 to 16 percent
Sand--20 to 45 percent
Organic carbon--.5 to 1.5 percent
Reaction--5.4 to 6.3
COMPETING SERIES: none
GEOGRAPHIC SETTING:
*Elevation--50 to 400 m
*Climate--warm, moist summers; cold, dry winters
*Mean annual precipitation--455 to 550 mm
*Mean annual air temperature-- -5 to -1 degrees C
*Frost-free period--55 to 90 days
GEOGRAPHICALLY ASSOCIATED SOILS:
*
Nuna--aquic conditions at soil surface, thickness of organic layers greater than 40 cm; thermokarst depressions on terraces
*
Blackcove--aquic conditions at soil surface, thickness of organic layers greater than 40 cm; depressions
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
*Drainage class--moderately well drained
*Saturation during normal years--saturated from a depth of 50 to 100 cm for about 2 weeks during the growing season
*Saturated hydraulic conductivity (Ksat)--very high in the surface organic layer, moderately high throughout the rest of the profile
USE AND VEGETATION:
Use--wildlife habitat, recreation, subsistence
Potential native vegetation--Moss, resin birch, cup lichen, reindeer lichen, greygreen reindeer lichen, star reindeer lichen, marsh Labrador tea, black spruce, polytrichum moss, sphagnum, bog blueberry Bigelow's sedge, black crowberry, lingonberry, dwarf birch, Schreber's big red stem moss, cloudberry, Bebb willow, beaverd spirea, woodland horsetail
DISTRIBUTION AND EXTENT: Nulato Hills-Southern Seward Peninsula Highlands, Alaska; MLRA 240; 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 47 to 122 cm
*Folistic epipedon--zone from 0 to 22 cm
*Cambic horizon--zone from 22 to 50 cm
*Cryoturbation--zone from 22 to 85 cm
*Depleted matrix--zone from 50 to 85 cm
*Redoximorphic concentrations--zone from 50 to 150 cm
*Redoximorphic depletions with chroma 2 or less--zone from 85 to 150 cm
*Aquic conditions--zone from 50 to 150 cm
*Lithological discontinuity--zone from 85 to 150 cm
National Cooperative Soil Survey
U.S.A.