LOCATION PEGATI AK
Established Series
SAS/TJR/MR
02/2022
PEGATI SERIES
Landscape--mountains, drift plains
Landform--swales and valley sides
Slope--2 to 40 percent
Parent material--colluvium with volcanic ash influence in the upper part
Mean annual precipitation--about 1200 mm
Mean annual air temperature--about 0 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: Medial over loamy, amorphic over isotic, nonacid Typic Cryaquands
TYPICAL PEDON: Pegati medial sandy loam on a north-northeast-facing, linear and concave swale of a mountain, on a slope of 17 percent at an elevation of 156 m (When described on August 7, 2013, the soil was moist to a depth of 61 cm and saturated throughout the rest of the profile.)
Oi--0 to 2 cm; slightly decomposed plant material; many very fine and fine and common medium to very coarse roots; very strongly acid (pH 4.7); clear irregular boundary
A--2 to 13 cm; medial sandy loam, dark reddish gray (5YR 4/2) dry, dark reddish brown (5YR 2.5/2) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine and common fine to very coarse roots; strongly acid (pH 5.1); clear irregular boundary
AB1--13 to 26 cm; medial sandy loam, matrix color 60 percent brown (7.5YR 5/3) dry, dark brown (7.5YR 3/3) moist, 20 percent pale brown (10YR 6/3) dry, brown (10YR 4/3) moist, and 20 percent grayish brown (10YR 5/2) dry, very dark grayish brown (10YR 3/2) moist; weak medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and fine roots; moderately acid (pH 5.7); clear smooth boundary
AB2--26 to 38 cm; medial sandy loam, brown (7.5YR 5/3) dry, dark brown (7.5YR 3/3) moist; weak medium granular structure; slightly hard, friable, nonsticky and nonplastic; common very fine and fine roots; 10 percent very coarse iron depletions, dark grayish brown (10YR 4/2) moist, clear boundaries, and 20 percent very coarse masses of oxidized iron, dark reddish brown (5YR 3/4) moist, clear boundaries; 1 percent gravel; moderately acid (pH 6.0); clear smooth boundary
Bg--38 to 60 cm; gravelly medial loam, yellowish brown (10YR 5/4) dry, dark yellowish brown (10YR 3/4) moist; moderate fine granular structure; slightly hard, friable, slightly sticky and nonplastic; common very fine and fine roots; 35 percent iron depletions, brown (10YR 4/3) moist, diffuse boundaries, and 5 percent medium masses of oxidized iron, brown (7.5YR 4/4) moist, diffuse boundaries; 18 percent gravel; slightly acid (pH 6.1); clear smooth boundary
2Cg--60 to 150 cm; gravelly sandy loam, light yellowish brown (10YR 6/4) dry, dark yellowish brown (10YR 4/4) moist; massive; soft, very friable, moderately sticky and nonplastic; 30 percent very coarse iron depletions, olive brown (2.5Y 4/3) moist, clear boundaries, and 3 percent medium masses of oxidized iron, strong brown (7.5YR 4/6) moist, clear boundaries; 25 percent gravel; moderately acid (pH 5.9)
TYPE LOCATION: Dillingham Census Area, Alaska, about 50 km west-northwest of the city of Dillingham; latitude 59.2353398, longitude -159.2148575, datum WGS 84 (coordinates determined with a GPS)
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--0 to 3 degrees C
Soil moisture control section--saturated in some part during much of the growing season (aquic moisture regime)
Depth to aquic conditions--25 to 50 cm below the mineral soil surface
Lithology of rock fragments--sedimentary, volcanic
Other features--lithologic discontinuity; andic soil properties; umbric epipedon; cambic horizon; redoximorphic concentrations and depletions
Layers influenced by volcanic ash
*Thickness--36 to 90 cm
*Phosphorous retention--70 to 100 percent
*Bulk density--0.45 to 0.9 g/cm3
*Ammonium oxalate Al plus 1/2 Fe--2 to 6 percent
*Volcanic glass content--5 to 50 percent
*Ammonium oxalate Si--0.5 to 1.0 percent
*Ammonium oxalate Fe--0.5 to 2.1 percent
Loamy part of particle-size control section
*Clay content--10 to 22 percent
*Sand content--50 to 75 percent
*Total rock fragment content--0 to 35 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--2 to 14 cm
A horizon
Hue--5YR, 7.5YR, 10YR
Value--2 or 2.5 moist, 4 or 5 dry
Chroma--1 or 2 moist
Fine-earth texture--medial sandy loam, sandy loam
Clay content--5 to 10 percent
Reaction--5.0 to 6.0
Gravel content--0 to 20 percent
Thickness--2 to 15 cm
Bulk density--0.45 to 0.9 g/cm3
Phosphorous retention--70 to 100 percent
Volcanic glass content--0 to 20 percent
Base saturation--0 to 30 percent
AB horizon
Hue--7.5YR, 10YR
Value--2 or 3 moist, 4 or 5 dry
Chroma--2 or 3 moist
Fine-earth texture--medial sandy loam, medial silt
Clay content--5 to 10 percent
Reaction--4.9 to 6.0
Gravel content--0 to 15 percent
Combined thickness--20 to 60 cm
Bulk density--0.5 to 0.9 g/cm3
Phosphorous retention--70 to 100 percent
Volcanic glass content--5 to 40 percent
Ammonium oxalate Al plus 1/2 Fe--2 to 6 percent
Base saturation--0 to 30 percent
Bg horizon
Hue--2.5Y, 10YR
Value--3 or 4 moist, 5 or 6 dry
Chroma--2 to 4 moist
Fine-earth texture--medial silt loam, medial sandy loam, medial loam
Clay content--5 to 10 percent
Reaction--5.0 to 6.5
Total rock fragment content--5 to 35 percent
Gravel content--0 to 35 percent
Cobble content--0 to 10 percent
Thickness--15 to 30 cm
Bulk density--0.5 to 0.9 g/cm3
Phosphorous retention--70 to 100 percent
Volcanic glass content--5 to 40 percent
Ammonium oxalate Al plus 1/2 Fe--2 to 6 percent
2Cg horizon
Hue--10YR, 2.5Y
Value--3 to 5 moist, 5 to 7 dry
Chroma--3 or 4 moist
Fine-earth texture--sandy loam, sandy clay loam, very fine sandy loam
Clay content--10 to 22 percent
Reaction--5.5 to 6.5
Total rock fragment content--0 to 35 percent
Gravel content--0 to 35 percent
Cobble content--0 to 10 percent
Thickness--more than 50 cm
COMPETING SERIES: None
GEOGRAPHIC SETTING:
Elevation--10 to 700 m
Climate--warm, moist summers; cold, moist winters
Mean annual precipitation--620 to 2100 mm
Mean annual air temperature-- -3.4 to 1.8 degrees C
Frost-free period--70 to 140 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Klak--no aquic conditions; mountain slopes
Nagugun--no aquic conditions; glaciated plains
Awayak--frequent flooding; no andic soil properties; no cambic horizon; flood plains
Pungokepuk--spodic horizon; ochric epipedon; swales of plains
Ungalikthluck--occasional flooding; no andic soil properties; no cambic horizon; flood plains
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--somewhat poorly drained
Saturation in normal years--below a depth of 0 to 25 cm in April through June, below a depth of 25 to 65 cm throughout the rest of the year
Saturated hydraulic conductivity (Ksat)--moderately high to very high in the A, AB, and Bg horizons, moderately low to high in the 2Cg horizon
USE AND VEGETATION:
Use--wildlife habitat, recreation, subsistence
Potential natural vegetation--bluejoint, fireweed, field horsetail, woolly geranium, western oakfern, splendid feather moss, Barclay's willow, Canadian burnet, tealeaf willow, beauverd spirea
DISTRIBUTION AND EXTENT: Ahklun Mountains, Alaska; MLRA 237; moderate extent
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: WASILLA, ALASKA
SERIES ESTABLISHED: Togiak National Wildlife Refuge-Ahklun Mountains Area, Alaska; 2019
REMARKS:
Diagnostic horizons and other features in this pedon
*Particle-size control section--zone from 2 to 102 cm
*Umbric epipedon--A and AB horizons
*Andic soil properties--zone from 2 to 60 cm
*Cambic horizon--Bg horizon
*Redoximorphic depletions--AB2, Bg, and 2Cg horizons
*Redoximorphic iron concentrations--zone from 26 to 150 cm
*Aquic conditions--zone from 26 to 150 cm
See laboratory pedon number 13N0049, layer 13N00125, for Bw horizon that has andic soil properties and amorphic mineralogy.
National Cooperative Soil Survey
U.S.A.