LOCATION NIGAG AK
Established Series
SAS/TJR/MPR
05/2022
NIGAG SERIES
Landscape--mountains, hills
Landform--mountain slopes, hillslopes
Slope--15 to 40 percent
Parent material-colluvium influenced by volcanic ash over till
Mean annual precipitation--about 1200 mm
Mean annual air temperature--about 0 degrees C
Depth class--moderately deep
Drainage class--well drained
Soil moisture regime--udic
Soil temperature regime--cryic
Soil moisture subclass--typic
TAXONOMIC CLASS: Medial over loamy-skeletal, ferrihydritic over isotic Andic Humicryods
TYPICAL PEDON: Nigag silt loam on south-southwest-facing, convex glaciated mountain footslope, on a slope of 15 percent at an elevation of 216 m (The soil was moist throughout when described on July 26, 2012.)
Oe--0 to 9 cm; moderately decomposed plant material; nonsticky and nonplastic; common fine and medium and many very fine and coarse roots; very strongly acid (pH 4.9); clear wavy boundary
E/A--9 to 12 cm; ashy silt loam; E part--55 percent pink (5YR 7/3) dry, reddish brown (5YR 5/3) moist, weak medium subangular blocky structure, slightly hard, friable, nonsticky and nonplastic, common very fine to medium roots, 3 percent gravel, very strongly acid (pH 4.8), clear wavy boundary; A part--45 percent brown (7.5YR 4/2) dry, very dark brown (7.5YR 2.5/2) moist, weak medium subangular blocky structure, slightly hard, friable, nonsticky and nonplastic, common very fine to medium roots, 3 percent gravel, very strongly acid (pH 4.8), clear wavy boundary
Bhs1--12 to 24 cm; medial silt loam, 60 percent dark gray (5YR 4/1) dry, black (5YR 2.5/1) moist, and 40 percent reddish brown (5YR 5/3) dry, dark reddish brown (5YR 3/3) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine to medium roots; 3 percent gravel; very strongly acid (pH 4.8); clear wavy boundary
Bhs2--24 to 44 cm; medial silt loam, brown (7.5YR 4/3) dry, very dark brown (7.5YR 2.5/3) moist; weak medium subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; common very fine and fine roots; 5 percent gravel; strongly acid (pH 5.3); gradual smooth boundary
2BC--44 to 72 cm; very gravelly sandy loam, brown (10YR 5/3) dry, dark brown (10YR 3/3) moist; weak fine granular structure; soft, very friable, slightly sticky and nonplastic; common very fine and fine roots; 40 percent gravel; moderately acid (pH 5.8); clear smooth boundary
2Cd--72 to 150 cm; very gravelly loamy coarse sand, pale brown (10YR 6/3) dry, brown (10YR 4/3) moist; massive; hard, friable, nonsticky and nonplastic; 50 percent gravel; moderately acid (pH 5.8); clear smooth boundary
TYPE LOCATION: Bethel Census Area, Alaska, about 50 km north-northwest of the village of Togiak; about 565 m south and 32 m west of the northeast corner of section 19, T. 8 S., R. 66 W., Seward Meridian; Goodnews Bay B-5 U.S. Geological Survey quadrangle; latitude 59.4711111 degrees north, longitude 160.5611111 degrees west, datum WGS 84 (coordinates determined with a GPS)
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--0 to 2 degrees C
Soil moisture control section--dry less than 45 consecutive days in June through October (udic moisture regime)
Lithology of rock fragments in upper part of profile--sedimentary, volcanic
Depth to densic contact--50 to 100 cm (moderately deep)
Layers that have andic soil properties (E/A horizon in some pedons, Bhs horizon)
*Thickness--25 to 35 cm
*Phosphorous retention--85 to 100 percent
*Bulk density--0.45 to 0.9 g/cm3
*Ammonium oxalate Al plus 1/2 Fe--2 to 4 percent
*Volcanic ash content--10 to 75 percent
*Ammonium oxalate Si--0.2 to 0.5 percent
*Ammonium oxalate Fe--0.9 to 2.1 percent
Loamy-skeletal part of particle-size control section
*Clay content--3 to 12 percent
*Sand content--55 to 75 percent
*Total rock fragment content--35 to 85 percent
*Sodium fluoride pH--8.4 to 11.6
*Ratio of 1500 kPa water to measured clay--0.6 to 6.0
Oe horizon
Thickness--6 to 12 cm
E/A horizon (E material)
Hue--5YR, 7.5YR, 10YR
Value--4 or 5 moist, 6 or 7 dry
Chroma--1 to 3 moist
Fine-earth texture--ashy silt loam, medial silt loam, medial very fine sandy loam
Clay content--4 to 10 percent
Reaction--4.0 to 5.3
Total rock fragment content--0 to 20 percent
Gravel content--0 to 20 percent
Cobble content--0 to 3 percent
Stone content--0 to 3 percent
Thickness--3 to 13 cm
Bulk density--0.9 to 1.0 g/cm3
Phosphorous retention--75 to 100 percent
Volcanic glass content--30 to 75 percent
E/A horizon (A material)
Hue--7.5YR, 10YR
Value--2 or 3 moist, 4 or 5 dry
Chroma--1 to 3 moist
Fine-earth texture--ashy silt loam, medial silt loam, medial very fine sandy loam
Clay content--4 to 10 percent
Reaction--4.0 to 5.3
Total rock fragment content--0 to 20 percent
Gravel content--0 to 20 percent
Cobble content--0 to 3 percent
Stone content--0 to 3 percent
Thickness--3 to 13 cm
Bulk density--0.9 to 1.0 g/cm3
Phosphorous retention--75 to 100 percent
Volcanic glass content--0 to 40 percent
Bhs horizon
Hue--5YR, 7.5YR
Value--2.5 or 3 moist, 4 or 5 dry
Chroma--1 to 3 moist
Fine-earth texture--medial silt loam, medial very fine sandy loam, medial sandy loam
Clay content--4 to 10 percent
Reaction--4.7 to 5.7
Total rock fragment content--0 to 35 percent
Gravel content--0 to 35 percent
Cobble content--0 to 10 percent
Stone content--0 to 5 percent
Thickness--16 to 33 cm
Bulk density--0.55 to 0.80 g/cm3
Phosphorous retention--75 to 100 percent
Volcanic glass content--10 to 50 percent
Organic carbon content--6 to 15 percent
2BC horizon
Chroma--2 or 3 moist
Clay content--3 to 12 percent
Reaction--5.6 to 5.9
Total rock fragment content--35 to 85 percent
Gravel content--10 to 40 percent
Cobble content--0 to 20 percent
Stone content--0 to 75 percent
Thickness--19 to 31 cm
2Cd horizon
Hue--10YR, 2.5Y, 5Y
Value--2 to 5 moist, 4 to 7 dry
Chroma--2 or 3 moist
Fine-earth texture--sandy loam, loamy coarse sand
Clay content--4 to 12 percent
Reaction--5.6 to 5.9
Total rock fragment content--35 to 50 percent
Gravel content--10 to 50 percent
Cobble content--0 to 20 percent
Stone content--0 to 20 percent
Thickness--more than 62 cm
COMPETING SERIES: None
GEOGRAPHIC SETTING:
Elevation--5 to 700 m
Climate--warm, moist summers; cold, moist winters
Mean annual precipitation--640 to 2100 mm
Mean annual air temperature-- -2.8 to 1.8 degrees C
Frost-free period--70 to 140 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Ahklun--50 to 100 cm (moderately deep) to lithic bedrock; linear to concave mountain slopes
Awayak--no spodic horizon; no andic soil properties; frequent flooding; flood plains
Kashaiak--colluvial parent material; shallow to lithic bedrock; similar landforms
Klak--colluvial parent material; andic soil properties less than 25 cm thick; linear to concave mountain slopes
Nagugun--no albic material; linear slopes of glaciated plains
Pegati--aquic conditions below a depth of 26 cm; swales of mountains
Pungokepuk--redoximorphic concentrations; swales of plains
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--well drained
Saturated hydraulic conductivity (Ksat)--moderately high or high in the E/A and Bhs horizons; high or very high in the 2BC horizon; moderately low in the 2Cd horizon
USE AND VEGETATION:
Use--wildlife habitat, recreation, subsistence
Potential natural vegetation--dwarf birch, reindeer lichens, Lapland cornel, black crowberry, splendid feathermoss, marsh Labrador tea, knights plume moss, sphagnum mosses, beauverd spirea, bog blueberry, lingonberry
DISTRIBUTION AND EXTENT: Ahklun Mountains, Alaska; MLRA 237; moderate extent
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: WASILLA, ALASKA
SERIES ESTABLISHED: Togiak National Wildlife Refuge, Bethel Census Area, Alaska; 2019
REMARKS:
Diagnostic horizons and other features in this pedon
*Particle-size control section--zone from 39 to 72 cm
*Ochric epipedon
*Andic soil properties--Bhs horizon
*Spodic horizon--Bhs horizon
*Densic material--2Cd horizon
Laboratory pedon number 13N44524 (Bhs2 horizon)
National Cooperative Soil Survey
U.S.A.