LOCATION BONASILA                AK

Established Series
SAS/MPS
02/2022

BONASILA SERIES

Landscape--hills and mountains
Landform--hillslopes and mountain slopes
Slope--2 to 50 percent
Parent material--coarse loamy colluvium over gravelly colluvium
Mean annual precipitation--about 525 mm
Mean annual air temperature--about -3.5 degrees C
Depth class--very deep
Drainage class--well drained
Soil moisture regime--udic
Soil temperature regime--gelic
Soil moisture subclass--typic

TAXONOMIC CLASS: Loamy-skeletal, isotic, nonacid, subgelic Turbic Humigelepts

TYPICAL PEDON: Bonasila silt on a northwest facing linear, convex backslope, on a slope of 9 percent at an elevation of 352 m (The soil was moist to 120 cm when described on June 22, 2018.)

Oe--0 to 3 cm; moderately decomposed plant material, brown (7.5YR 4/2) dry, very dark brown (7.5YR 2.5/2) moist; nonsticky, nonplastic; many very fine roots and common fine, medium, and coarse roots; very strongly acid (pH 5.0); clear irregular boundary

Ajj1--3 to 9 cm; silt, brown (7.5YR 4/2) dry, very dark brown (7.5YR 2.5/2) moist; weak coarse granular structure; friable, nonsticky, nonplastic; weakly smeary; common very fine, fine, medium, and coarse roots; few medium and common fine irregular pores; 2 percent gravel; strongly acid (pH 5.2); clear irregular boundary

Ajj2--9 to 27 cm; highly organic silt, brown (10YR 5/3) dry, dark brown (10YR 3/3) moist; weak coarse subangular blocky structure; friable, nonsticky, nonplastic; weakly smeary; common very fine and fine roots; common fine irregular pores; 5 percent medium distinct lenticular noncemented strong brown (7.5YR 4/6) masses of oxidized iron with clear boundaries in matrix and 5 percent coarse distinct lenticular noncemented dark grayish brown (2.5Y 4/2) masses of reduced iron with clear boundaries; 5 percent gravel; moderately acid (pH 5.9); gradual irregular boundary

Bw/Ajj--27 to 60 cm; gravelly very fine sandy loam, 70 percent pale brown (10YR 6/3) and 30 percent brown (10YR 5/3) dry, 70 percent brown (10YR 4/3) and 30 percent dark brown (10YR 3/3) moist; moderate coarse subangular blocky structure; friable, nonsticky, nonplastic; common very fine and fine roots; 15 percent gravel; moderately acid (pH 6.0); clear smooth boundary

2BC--60 to 80 cm; extremely gravelly very fine sandy loam, pale brown (10YR 6/3) dry, brown (10YR 4/3) moist; weak medium granular structure; friable, slightly sticky, nonplastic; common very fine roots; 65 percent gravel; moderately acid (pH 5.7); gradual smooth boundary

2C--80 to 150 cm; extremely gravelly loam, light brownish gray (2.5Y 6/2) dry, dark grayish brown (2.5Y 4/2) moist; massive; very friable, slightly sticky, nonplastic; common very fine roots; 60 percent gravel; moderately acid (pH 5.6)

TYPE LOCATION: Nome Census Area County, Alaska, latitude 63.3729888, longitude -160.7790615 degrees, datum WGS84 (Coordinates determined with a GPS unit)

RANGE IN CHARACTERISTICS:
Mean annual soil temperature-- -2 to 0 degrees C
Soil moisture control section--dry less than 45 consecutive days in June through October
Thickness of umbric epipedon--18 to 45 cm
Thickness of cambic horizon--25 to 85 cm
Thickness of gelic materials--13 to 57 cm

Particle Size Control Section:
*Clay--2 to 16 percent
*Total fragments--35 to 65 percent gravels, cobbles
*Sodium fluoride pH--8.4 to 11.6
*Ratio of 1500 kPa water to measured clay--0.6 to 6.0

Oe horizon
Thickness--3 to 14 cm

Ajj1 horizon
Hue--7.5YR or 10YR
Value--2 or 2.5 moist, 4 to 6 dry
Chroma--1 or 2
Fine-earth texture--silt, silt loam
Clay--3 to 10 percent
Sand--10 to 35 percent
Organic carbon--8 to 12 percent
Total rock fragment content--0 to 5 percent gravel
Reaction--4.7 to 5.5
Thickness--5 to 15 cm

Ajj2 horizon
Hue--7.5YR or 10YR
Value--2 to 3 moist, 4 or 5 dry
Chroma--2 or 3
Fine-earth texture--silt, silt loam
Clay--5 to 12 percent
Sand--10 to 35 percent
Organic carbon--5 to 9 percent
Total rock fragment content--0 to 5 percent gravel
Reaction--4.8 to 5.9
Thickness--10 to 18 cm

Bw/Ajj horizon
Hue--7.5YR or 10YR
Value--2.5 to 4 moist, 4 to 6 dry
Chroma--2 to 4
Fine-earth texture--very fine sandy loam, sandy loam, silt loam
Clay--2 to 12 percent
Sand--35 to 70 percent
Organic carbon--3 to 8 percent
Total rock fragment content--10 to 35 percent
Total gravel content--10 to 25 percent
Total cobble content--0 to 10 percent
Reaction--5.1 to 6.1
Thickness--10 to 35 cm

2BC horizon
Hue--10YR or 2.5Y
Value--4 or 5 moist, 6 or 7 dry
Chroma--3 or 4
Fine-earth texture--very fine sandy loam, fine sandy loam, loam
Clay--5 to 17 percent
Sand--35 to 55 percent
Organic carbon--1 to 2 percent
Total rock fragment content--35 to 70 percent
Total gravel content--10 to 65 percent
Total cobble content--0 to 25 percent
Reaction--5.0 to 6.2
Thickness--15 to 50 cm

2C horizon
Hue--10YR or 2.5Y
Value--3 or 6 moist, 5 or 8 dry
Chroma--2 to 4
Fine-earth texture--sandy loam, silt loam, loam
Clay--8 to 17 percent
Sand--35 to 60 percent
Organic carbon--.2 to 1.5 percent
Total rock fragment content--40 to 80 percent
Total gravel content--5 to 80 percent
Total cobble content--0 to 40 percent
Reaction--5.0 to 6.2

COMPETING SERIES: none

GEOGRAPHIC SETTING:
*Elevation--5 to 800 m
*Climate--warm, moist summers; cold, dry winters
*Mean annual precipitation--350 to 700 mm
*Mean annual air temperature-- -6 to -1 degrees C
*Frost-free period--45 to 90 days

GEOGRAPHICALLY ASSOCIATED SOILS:
* Paugna--no cryoturbation present; organic carbon ranges to 5 percent in umbric epipedon; upper backslopes on mountains
* Golsovia--cryic soil temperature regime, no cryoturbation present, moderately deep to paralithic contact; backslopes and nose slopes of hills and escarpments
*MountMcDonald--shallow to lithic bedrock; summits and shoulders of mountains

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
*Drainage class--well drained
*Saturation during normal years--saturated for less than 2 weeks during June to a depth of above 25 to 50 cm
*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--tealeaf willow, netleaf willow, black crowberry, marsh Labrador tea, bog blueberry, dwarf birch, splendid feather moss, Schreber's big red stem moss, moss, reindeer lichen, star reindeer lichen, greygreen reindeer lichen, beaverd spirea, fescue, lingonberry, polytrichum moss, knights plume moss, abietinella moss, juniper polytrichum moss

DISTRIBUTION AND EXTENT: Nulato Hills-Southern Seward Peninsula Highlands, Alaska; MLRA 240; moderate 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 28 to 103 cm
*Umbric epipedon--zone from 3 to 27 cm
*Cryoturbation--zone from 3 to 60 cm
*Redoximorphic concentrations--zone from 9 to 27 cm
*Cambic horizon-- zone from 27 to 80 cm
*Lithological discontinuity-- zone from 60 to 150 cm

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National Cooperative Soil Survey
U.S.A.