LOCATION SWIFTRIVER AK
Established Series
SAS/MPS/TJR
02/2022
SWIFTRIVER SERIES
Landscape--valleys
Landform--floodplain
Slope--0 to 10 percent
Parent material--loamy alluvium over sandy and gravelly alluvium
Mean annual precipitation--about 485 mm
Mean annual air temperature--about -3 degrees C
Depth class--very deep
Drainage class--somewhat poorly drained
Soil moisture regime--aquic
Soil temperature regime--cryic
Soil moisture subclass--typic
TAXONOMIC CLASS: Coarse-loamy over sandy or sandy-skeletal, mixed, superactive, nonacid Fluvaquentic Cryaquepts
TYPICAL PEDON: Swiftriver silt on a linear, linear floodplain on a slope of 0 percent at an elevation of 93 m (The soil was wet, satiated, from 68 to 150 cm and moist from 0 to 68 cm when described on July 19, 2016.)
A1--0 to 6 cm; silt, gray (7.5YR 5/1) dry, very dark gray (7.5YR 3/1) moist; weak, fine, granular structure; very friable, nonsticky, nonplastic; common very fine and medium, and many fine roots; neutral (pH 6.9); clear irregular boundary
A2--6 to 25 cm; silt, grayish brown (10YR 5/2) dry, very dark grayish brown (10YR 3/2) moist; weak, medium, granular structure; friable, nonsticky, nonplastic; common very fine, medium, and fine roots; neutral (pH 6.7); clear smooth boundary
Bg--25 to 44 cm; silt and fine sandy loam, dark gray (N 4/), dry, black (N 2.5/), moist; weak, coarse, subangular blocky structure; friable, nonsticky, nonplastic; common very fine and fine roots; common medium tubular pores; 5 percent medium irregular dark reddish brown (5YR 3/4) masses of oxidized iron with clear boundaries on surfaces along root channels and 5 percent medium irregular dark reddish brown (5YR 3/4) masses of oxidized iron with clear boundaries lining pores and 5 percent medium irregular dark reddish brown (5YR 3/4) masses of oxidized iron with clear boundaries in matrix; neutral (pH 6.6); abrupt irregular boundary
2Cg--44 to 150 cm; extremely gravely sand, gray (2.5Y 5/1) dry, very dark gray (2.5Y 3/1) moist; single grain; loose, nonsticky, nonplastic; 10 percent cobbles, 50 percent gravel; neutral (pH 6.7)
TYPE LOCATION: Nome Census Area, Alaska, latitude 63.6100800 longitude -160.8882200 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--saturated in all parts below a depth of 25 to 50 cm during much of the growing season (aquic moisture regime)
Thickness umbric epipedon--20 to 30 cm
Depth to redoximorphic features--25 to 50 cm
Depth to reduced matrix-25 to 50 cm
Depth to aquic conditions--25 to 50 cm
Particle Size Control Section:
Loamy portion of the particle size control section:
*Clay--5 to 15 percent
Sandy portion of the particle size control section:
*Clay--3 to 8 percent
*Total fragments--40 to 60 percent gravel
A1 horizon
Hue--7.5YR or 10YR
Value--2 to 4 moist, 4 to 6 dry
Chroma--1 to 3
Fine-earth texture--silt, silt loam, loamy fine sand
Clay--3 to 10 percent
Sand--5 to 75 percent
Organic carbon--5 to 8 percent
Reaction--5.5 to 6.7
Thickness--2 to 10 cm
A2 horizon
Hue--7.5YR or 10YR
Value--2 to 4 moist, 4 to 6 dry
Chroma--1 to 3
Fine-earth texture--silt, silt loam, loamy fine sand
Clay--5 to 12 percent
Sand--5 to 65 percent
Organic carbon--3 to 5 percent
Reaction--5.5 to 6.9
Thickness--10 to 25 cm
Bg horizon
Hue--5Y or N
Value--2.5 to 4 moist, 4 or 6 dry
Chroma--0 to 2
Fine-earth texture--silt, silt loam, fine sandy loam
Clay--5 to 15 percent
Sand--10 to 75 percent
Organic carbon--3 to 5 percent
Reaction--6.1 to 6.9
Thickness--15 to 55 cm
2Cg horizon
Hue--2.5Y or 5Y
Value--2.5 or 3 moist, 4 or 5 dry
Chroma--1 to 3
Fine-earth texture--loamy sandy, sand
Clay--3 to 8 percent
Sand--75 to 95 percent
Organic carbon--0.5 to 2 percent
Total rock fragment content--40 to 80 percent
Total gravel content--40 to 60 percent
Total cobble content--0 to 10 percent
Reaction--6.0 to 7.0
Thickness--40 to 110 cm
COMPETING SERIES: none
GEOGRAPHIC SETTING:
*Elevation--50 to 750 m
*Climate--warm, moist summers; cold, dry winters
*Mean annual precipitation--375 to 655 mm
*Mean annual air temperature-- -5 to -1 degrees C
*Frost-free period--55 to 90 days
GEOGRAPHICALLY ASSOCIATED SOILS:
*
Teacreek--loamy-skeletal particle size class, folistic epipedon, clay ranges above 18 percent; hillslopes and mountain slopes
*
Cilla--loamy-skeletal particle size class, no aquic conditions; hillslopes
*
Nulatohills--no aquic conditions present, no redoximorphic features, volcanic ash and colluvium, mountain slopes
*
Paugna--loamy-skeletal particle size class, gelic soil temperature regime; mountain slopes
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
*Drainage class--somewhat poorly drained
*Flooding--frequent, brief
*Saturation during normal years--saturated from between a depth of 25 to 50 cm in June through October
*Saturated hydraulic conductivity (Ksat)--high to moderately high in the upper part of the profile, very high in the lower part of the profile
USE AND VEGETATION:
Use--wildlife habitat, recreation, subsistence
Potential native vegetation--larkspurleaf monkshood, green alder, wideleaf polargrass, bluejoint, fireweed, meadow horsetail, horsetail, northern bedstraw, tall bluebells, Schreber's big red stem moss, tall Jacob's ladder, arctic raspberry, feltleaf willow, saxifrage, tealeaf willow, bluegrass, bedstraw, Blandow's helodium moss, moss
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 25 to 100 cm
*Umbric epipedon--zone from 0 to 25 cm
*Aquic conditions--zone from 25 to 150 cm
*Redoximorphic concentrations--zone from 25 to 44 cm
*Reduced matrix--zone from 25 to 150 cm
*Lithological discontinuity--zone from 44 to 150 cm
________________________________________
National Cooperative Soil Survey
U.S.A.