LOCATION ALAPAA                  AK

Established Series
MPS/SAS/TJR
02/2022

ALAPAA SERIES

Landscape--plains
Landform--lava plain
Slope--3 to 6 percent
Parent material--loess over residuum weathered from basalt
Mean annual precipitation--about 500 mm
Mean annual air temperature--about -3 degrees C
Depth class--very deep
Drainage class--well drained
Soil moisture regime--udic
Soil temperature regime--cryic
Soil moisture subclass--typic

TAXONOMIC CLASS: Fragmental, mixed Typic Cryorthents

TYPICAL PEDON: Alapaa very bouldery ashy silt loam on a south, southeast facing linear, linear lava plain on a slope of 4 percent at an elevation of 223 m (The soil was moist throughout when described on June 26, 2016.)

Oe--0 to 5 cm; very boulder moderately decomposed plant material, dark gray (7.5YR 4/1) dry, black (7.5YR 2.5/1) moist; few fine and common very fine roots; 25 percent boulders, 30 percent stones; extremely acid (pH 3.9)

Bs--5 to 13 cm; very bouldery ashy silt loam, brown (7.5YR 5/4) dry, dark brown (7.5YR 3/4) moist; weak medium subangular blocky structure; very friable, nonsticky, slightly plastic; few fine and very fine roots; common fine irregular pores; 25 percent stones, 30 percent boulders; moderately acid (pH 5.6)

C--13 to 150 cm; boulders; 30 percent subrounded stones, 70 percent subrounded boulders ; moderately acid (pH 5.6)

TYPE LOCATION: Nome Census Area County, Alaska, latitude 63.3378210 longitude -161.7192530 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 of ochric epipedon--5 to 15 cm
Thickness of andic soil properties--5 to 15 cm

Particle Size Control Section:
*Clay--2 to 10 percent
*Total fragments--90 to 100 percent basalt stones, boulders

Oe horizon
Total rock fragment content--40 to 70 percent
Total stone content--20 to 35 percent
Total boulder content--20 to 35 percent
Thickness--2 to 8 cm

Bs horizon
Hue--7.5YR or 10YR
Value--4 or 5 moist, 6 to 7 dry
Chroma--3 to 6
Fine-earth texture--silt, silt loam
Clay--2 to 8 percent
Sand--5 to 25 percent
Organic carbon--5 to 10 percent
Total rock fragment content--35 to 60 percent
Total stone content--0 to 25 percent
Total boulder content--20 to 50 percent
Oxalate Fe--1 to 3 percent
Phosphorous retention--85 to 100 percent
Reaction--5.4 to 6.0
Thickness-- 5 to 10 cm

C horizon
Organic carbon--0.0 to 0.5 percent
Total rock fragment content--90 to 100 percent
Total stone content--0 to 30 percent
Total boulder content--70 to 100 percent
Thickness--125 to 140 cm

COMPETING SERIES: none

GEOGRAPHIC SETTING:
*Elevation--50 to 550 m
*Climate--warm, moist summers; cold, dry winters
*Mean annual precipitation--380 to 600 mm
*Mean annual air temperature-- -5 to -1 degrees C
*Frost-free period--55 to 90 days

GEOGRAPHICALLY ASSOCIATED SOILS:
* Akpik--loamy-skeletal, gelic temperature regime, isotic mineralogy, depth to aquic conditions 0 to 25cm (poorly drained); talfs on plains
* Wagonboxcreek--umbric epipedon, medial over loamy; swales on lava fields
* Sikinik--histic epipedon, coarse-loamy; plains and toeslopes of hills
* Apun--histic epipedon, coarse-loamy; footslopes on hills or mountains

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
*Drainage class--well drained
*Saturation during normal years--none
*Saturated hydraulic conductivity (Ksat)-- very high in the surface organic layer and the fragmental soil layers, moderately high or high throughout the rest of the profile

USE AND VEGETATION:
Use--wildlife habitat, recreation, subsistence
Potential native vegetation--crustose lichen, lichen, dwarf birch, bryocaulon lichen, Bigelow's sedge, reindeer lichen, star reindeer lichen, pincushion plant, black crowberry, beaverd spirea, snow lichen, witch's hair lichen, alpine sweetgrass, cup lichen, greygreen reindeer lichen, meadow horsetail, marsh Labrador tea, alpine azalea, tealeaf willow, whiteworm lichen

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 30 to 105 cm
*Ochric epipedon--zone from 0 to 5cm
*Andic soil properties--zone from 5 to 13 cm

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National Cooperative Soil Survey
U.S.A.