LOCATION UMILGUK AK
Established Series
BMC/CBB
11/2024
UMILGUK SERIES
Depth class: very deep
Drainage class: somewhat poorly drained
Parent material: loamy slope alluvium derived from sedimentary rock
Landscape: hills
Landform: hillslopes
Slopes: 5 to 25 percent
Mean annual precipitation: about 500 mm (20 in)
Mean annual air temperature: about -3 degrees C. (27 degrees F.)
Frost-free period: 75 to 90 days
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive Typic Cryaquolls
TYPICAL PEDON: Umilguk silt in a white spruce forest on an east facing convex, linear nose slope on a slope of 18 percent at an elevation of 418 m (1371 ft)
Oa--0 to 10 cm (0 to 4 in); highly decomposed plant material, black (10YR 2/1) broken face moist, dark gray (10YR 4/1) dry; common very fine, fine, medium, coarse, and very coarse roots throughout; strongly acid (pH 5.2); clear wavy boundary (5 to 14 cm, 2 to 6 in thick)
A--10 to 36 cm (4 to 14 in); silt, 85 percent very dark brown (10YR 2/2) broken face and 15 percent dark brown (10YR 3/3) broken face moist, 85 percent dark grayish brown (10YR 4/2) and 15 percent brown (10YR 5/3) dry; weak medium subangular blocky structure; very friable, soft, nonsticky, nonplastic; nonsmeary; common very fine, fine, and medium roots throughout; very fine and fine irregular and medium tubular pores; 10.89 % of SOM; 6.32 % of SOC; moderately acid (pH 5.6); clear smooth boundary. (20 to 40 cm, 8 to 16 in thick)
Bw--36 to 48 cm (14 to 19 in); silt loam, dark grayish brown (2.5Y 4/2) broken face moist, light brownish gray (2.5Y 6/2) dry; weak medium granular structure; very friable, soft, nonsticky, nonplastic; nonsmeary; common very fine, fine, and medium roots throughout; very fine and fine irregular and medium tubular pores; 2 percent faint brown (7.5YR 4/3) masses of oxidized iron; 1.71 % of SOC; 2.94 % of SOM; moderately acid (pH 5.7); clear smooth boundary (5 to 14 cm, 2 to 6 in thick)
Cg1--48 to 80 cm (19 to 32 in); silt loam, dark grayish brown (2.5Y 4/2) broken face moist, light brownish gray (2.5Y 6/2) dry; 2 percent black (10YR 2/1) mottles; massive; friable, slightly hard, nonsticky, nonplastic; nonsmeary; common very fine roots throughout; very fine and fine irregular pores; 10 percent prominent reddish yellow (7.5YR 6/6), moist, masses of oxidized iron; 1 percent gravel; 1.17 % of SOC; 2.02 % of SOM; moderately acid (pH 5.7); gradual smooth boundary. (20 to 65 cm, 8 to 26 in thick)
Cg2--80 to 200 cm (32 to 79 in); loam, dark grayish brown (2.5Y 4/2) broken face moist, light brownish gray (2.5Y 6/2) dry; massive; firm, moderately hard, nonsticky, slightly plastic; nonsmeary; very fine and fine irregular pores; 10 percent prominent reddish yellow (7.5YR 6/6), moist, masses of oxidized iron; 3 percent gravel; 0.58 % of SOC; 1 % of SOM; neutral (pH 6.6). (72 to 150 cm, 28 to 59 in thick)
TYPE LOCATION: Nulato Hills - Continental Divide and Blackburn Hills Soil Survey Area, Alaska; latitude 64 degrees 19 minutes 18.80 seconds north, longitude 159 degrees 52 minutes 51.60 seconds west, datum WGS84, UTM north 7133179.08 and UTM east 457405.83, zone 4W, datum WGS84.
RANGE IN CHARACTERISTICS:
Soil moisture regime: aquic
Soil temperature regime: cryic
Mean annual soil temperature: 0 to 3 degrees C. (32 to 37 degrees F.)
Thickness of organic material: 5 to 14 cm (2 to 6 in)
Thickness of mollic epipedon: 20 to 40 cm (8 to 16 in)
Depth to redoximorphic concentrations: 30 to 50 cm (12 to 20 in)
Depth to reduced matrix: 30 to 50 cm (12 to 20 in)
Depth to aquic conditions: 30 to 50 cm (12 to 20 in)
Oa horizon:
Hue: 10YR or 7.5YR
Value: 2 to 3 moist, 4 to 5 dry
Chroma: 1 to 2
Texture: highly decomposed plant material
Organic matter: 60 to 90 percent
Reaction class: very strongly acid to moderately acid (pH 4.5 to 6.0)
A horizon:
Hue: 10YR or 2.5Y
Value: 2 to 3 moist, 4 to 5 dry
Chroma: 1 to 3
Texture: silt or silt loam
Sand: 5 to 35 percent
Silt: 53 to 92 percent
Clay: 3 to 12 percent
Organic matter: 2 to 8 percent
Reaction class: strongly acid to neutral (pH 5.5 to 7.3)
Bw horizon:
Hue: 2.5Y
Value: 3 to 4 moist, 5 to 6 dry
Chroma: 2 to 4
Texture: silt loam or loam
Sand: 15 to 45 percent
Silt: 39 to 80 percent
Clay: 4 to 16 percent
Organic matter: 1 to 5 percent
Reaction class: moderately acid to neutral (pH 5.6 to 7.3)
Cg horizons:
Hue: 2.5Y or 5Y
Value: 4 to 5 moist, 6 to 7 dry
Chroma: 1 to 2
Texture: silt loam, loam, or their gravelly analogues
Sand: 20 to 52 percent
Silt: 30 to 75 percent
Clay: 5 to 18 percent
Rock fragments: 0 to 15 percent
Gravels: 0 to 15 percent
Organic matter: 0.4 to 3 percent
Reaction class: moderately acid to neutral (pH 5.6 to 7.3)
Some pedons have a Bw horizon greater than 14 cm thick and therefore a cambic horizon.
COMPETING SERIES: These are the
Bandarrow,
Habenome (OR),
Fourlog,
Venapass (WY), and
Rosane (CO & WY) series.
Bandarrow soils do not have a reduced matrix anywhere in the profile.
Habenome soils have buried A horizons and occur on basins and benches on glaciated mountain slopes.
Fourlog soils have many mica flakes in the substratum.
Venapass soils has stratified textures in the substratum and occur at 2,150 to 2,600 m (7,000 to 8,500 ft) elevation.
Rosane soils have sand and gravel textures at depths below 60 to 100 cm (24 to 39 in).
GEOGRAPHIC SETTING:
Elevation: 180 to 450 meters (590 to 1,475 feet)
Parent material: loamy slope alluvium derived from sedimentary rock
Landform: hillslopes
Slopes: 5 to 25 percent
Mean annual precipitation: 400 to 500 mm (16 to 20 in)
Mean annual air temperature: -5 to -1 degrees C. (23 to 30 degrees F.)
Frost free period: 75 to 90 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Muskox,
Tagluk,
Tuttu, and
Cilla soils.
Muskox soils have an umbric epipedon, are well drained, and occur on similar landforms on head slopes on swale microfeatures.
Tagluk soils have a folistic and mollic epipedon, are well drained, and occur on mountain slopes on backslope positions.
Tuttu soils have an umbric epipedon, andic soil properties, and occur on mountain slopes on backslope and footslope positions.
Cilla soils have an ochric epipedon, a cambic horizon, and occur on similar landforms on backslope positions.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class: somewhat poorly drained
Saturated Hydraulic Conductivity: very high in the Oa horizon, moderately high in the A horizon, and moderately high to high in the Bw and Cg horizons
Permeability: rapid to very rapid in the Oa horizon, moderate to the A horizon, and moderate to moderately rapid in the Bw and Cg horizons
Runoff: very high
USE AND VEGETATION:
Use: wildlife habitat, recreation, and subsistence
Native vegetation: tealeaf willow, woodland horsetail, bluejoint, bunchberry dogwood, beauverd spirea, white spruce, splendid feather moss, field horsetail, siberian alder, capitate valerian, fireweed, and spreading woodfern
DISTRIBUTION AND EXTENT: MLRA 240, Nulato Hills-Southern Seward Peninsula Highlands. The series is of moderate extent.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Wasilla, Alaska
SERIES ESTABLISHED: Nulato Hills - Continental Divide and Blackburn Hills Soil Survey, Alaska, 2024.
REMARKS: Diagnostic features and horizons recognized in this profile include:
Particle-size control section: 35 to 110 cm (14 to 43 in)
Mollic epipedon: 10 to 36 cm (4 to 14 in) (A horizon)
Redoximorphic concentrations: 48 to 200 cm (19 to 79 in) (Bw and Cg horizons)
Reduced matrix: 48 to 200 cm (19 to 79 in) (Bw and Cg horizons)
Aquic conditions: 48 to 200 cm (19 to 79 in) (Bw and Cg horizons)
ADDITIONAL DATA:
User pedon ID: 2021AK290680
National Cooperative Soil Survey
U.S.A.