LOCATION CLARKSPOINT             AK

Established Series
SAS/TJR/SJN
02/2022

CLARKSPOINT SERIES

The Clarkspoint series consists of very deep, well drained soils formed in volcanic ash over loess on rises of plains and on shoulders of hills. Slopes range from 2 to 40 percent. The mean annual precipitation is about 615 millimeters and the mean annual air temperature is about 0.5 degrees C.

TAXONOMIC CLASS: Medial over loamy, amorphic over isotic Vitric Fulvicryands

TYPICAL PEDON: Clarkspoint highly organic silt loam, located on a plain rise with a slope of 4 percent and elevation of 38 meters; when described on September 19th, 2007 the soil was moist throughout (Colors are for moist soil unless otherwise noted)

Oi--0 to 4 centimeters; slightly decomposed plant material; many very fine and fine roots, common medium roots, and few coarse roots; extremely acid, pH 4.4; clear smooth boundary

A--4 to 10 centimeters; very dark gray (7.5YR 3/1) highly organic silt loam; 20 percent sand; 73 percent silt; 7 percent clay; weak fine granular structure; very friable, nonsticky, nonplastic; many very fine and fine roots, few medium roots, and few coarse roots; extremely acid, pH 4.4; clear smooth boundary

Bhs--10 to 37 centimeters; dark brown (7.5YR 3/3) medial highly organic silt loam; 20 percent sand; 73 percent silt; 7 percent clay; moderate fine granular structure; very friable, nonsticky, nonplastic; many very fine and fine roots, few medium roots, and few coarse roots; very strongly acid, pH 5.0; clear wavy boundary

BC--37 to 67 centimeters; 35 percent light olive brown (2.5Y 5/3) and 30 percent brown (10YR 4/3) and 20 percent black (2.5Y 2.5/1) and 10 percent dark gray (10YR 4/1) ashy silt loam; 20 percent sand; 75 percent silt; 5 percent clay; moderate fine granular structure; very friable, nonsticky, nonplastic; many very fine and fine roots, common medium roots, and few coarse roots; 5 percent coarse dark reddish brown (5YR 3/4) masses of oxidized iron with sharp boundaries; noneffervescent; strongly acid, pH 5.1; abrupt wavy boundary

C--67 to 183 centimeters; 60 percent grayish brown (2.5Y 5/2) silt loam; 30 percent sand; 66 percent silt; 4 percent clay; massive structure; friable, nonsticky, nonplastic; few very fine and fine roots, few medium roots, and few coarse roots; 40 percent medium brown (7.5YR 5/4) masses of oxidized iron with clear boundaries; moderately acid, pH 6.0

TYPE LOCATION: Dillingham Census Area, Alaska; 1 kilometer east of the Village of Clarks Point; 58.8361111 degrees north latitude and 158.5388889 degrees west longitude.

RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 1.5 to 1.7 degree C (cryic soil temperature regime)
Soil moisture control section - Dry less than 45 consecutive days from June to October (udic soil moisture regime)
Thickness of umbric epipedon - 33 to 59 cm
Thickness of andic soil properties - 46 to 57 cm

All mineral horizons-
Reaction - 4.2 to 6.5
Volcanic glass content - 0 to 20 percent
Ammonium oxalate extractable AL + 1/2 Fe - 0.54 to 3.57 percent
Moist bulk density - 0.60 to 1.40 g/cc

Particle-size control section-
Clay content - 3 to 8
Rock fragments - 0 to 5 percent

Oi horizon
Thickness - 4 to 10 cm

A or AE horizon
Hue - 7.5YR
Value - 2.5 or 3
Chroma - 1 or 2
Fine earth texture - Highly organic silt loam or highly organic silt
Clay content - 5 to 8 percent
Reaction - 4.2 to 4.4
Rock fragments - 0 percent
Thickness - 6 to 16 cm

Bhs horizon
Hue - 5YR or 7.5YR
Value - 2.5 or 3
Chroma - 1 to 3
Fine earth texture - Medial highly organic silt loam or medial highly organic silt
Clay content - 5 to 8 percent
Reaction - 4.8 to 5.1
Rock fragments - 0 percent
Thickness - 22 to 27 cm

BC horizon
Hue - 7.5YR to 2.5Y
Value - 2.5 to 5
Chroma - 1 to 3
Fine earth texture - Medial silt loam or medial silt
Clay content - 3 to 8 percent
Reaction - 4.9 to 6.2
Rock fragments - 0 percent
Thickness - 24 to 30 cm

C horizon
Hue - 10YR or 2.5Y
Value - 4 or 5
Chroma - 2 to 4
Fine earth texture - Silt, silt loam, or very fine sandy loam
Clay content - 3 to 5 percent
Reaction - 5.6 to 6.5
Rock fragments - 0 to 5 percent medium to coarse subrounded gravel
Thickness - 111 to 116 cm

COMPETING SERIES: There are no competing series

GEOGRAPHIC SETTING:
Parent material - Organic material over coarse-silty volcanic ash over coarse-silty loess
Landform - Rises on plains, and hills
Slope - 2 to 40 percent
Elevation - 3 to 65 meters
Climate - Short, cool summers; long, cold winters
Mean annual precipitation - 612 to 625 mm
Mean annual air temperature - 0.2 to 0.6 degrees C
Frost free duration - 85 to 140 days

GEOGRAPHICALLY ASSOCIATED SOILS:
Rolph - No andic soil properties, similar landform position
Nushagak - Aquic conditions at surface, talfs on plains
Snagpoint - Shallow to loamy-skeletal parent material, similar landform position
Kemuk - Aquic conditions at surface, talfs on plains

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: (Ksat)
Drainage class - Well drained
Saturation in normal years - None
Flooding - None
Ponding - None
Ksat - Moderately high throughout the mineral soil, except moderately slow to moderately high in the C horizon

USE AND VEGETATION:
Use - Community development and wildlife habitat
Potential natural vegetation - Western maritime scrubland composed of alder, ferns, and grass.

DISTRIBUTION AND EXTENT: Bristol Bay Lowlands; MLRA 236; small extent

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: WASILLA, ALASKA

SERIES ESTABLISHED: Nushagak-Mulchatna Watershed Soil Survey, Dillingham Census Area, Alaska, 2019

REMARKS:
Particle-size control section - 4 to 104 cm
Umbric epipedon - A or AE, and Bhs horizons
Soil moisture regime - Udic
Andic soil properties - Bhs and BC horizons

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National Cooperative Soil Survey
U.S.A.