LOCATION CHUNILNA AK
Established Series
Rev. MHC/JPM/DLM
02/2022
CHUNILNA SERIES
Depth class: very deep
Drainage class: very poorly or poorly drained
Parent material: volcanic ash influenced loess over gravelly glacial till deposits
Landform: depressions on till plains, depressions on hill, and depressions on mountains
Slopes: 0 to 20 percent
Mean annual precipitation: about 28 inches
Mean annual temperature: about 33 degrees F.
TAXONOMIC CLASS: Medial over loamy-skeletal, amorphic over mixed, superactive, acid Typic Cryaquands
TYPICAL PEDON: Chunilna silt loam - on a level slope under paper birch forest at 450 feet elevation. (All colors are for moist soil, all textures are apparent field textures)
Oe--0 to 4 inches; brown (7.5YR 4/4) partially decomposed plant material; very strongly acid (pH 4.5). (2 to 5 inches thick)
A1--4 to 8 inches; very dark brown (10YR 2/2) mucky silt loam with occasional lenses of yellowish brown (10YR 5/8) fine sandy loam lenses of volcanic ash; weak fine subangular blocky structure; very friable, nonsticky and nonplastic; many very fine, fine and medium roots; very strongly acid (pH 4.6); clear smooth boundary. (3 to 8 inches thick)
A2--8 to 13 inches; dark brown (10YR 3/3) silt loam with occasional lenses of yellowish brown (10YR 5/8) fine sandy loam and very fine sandy loam lenses of volcanic ash; weak fine subangular blocky structure; very friable, nonsticky and nonplastic; common very fine and fine roots; very strongly acid (pH 4.8); clear smooth boundary. (0 to 5 inches thick)
Bg--13 to 18 inches; brown (10YR 4/3) silt loam; weak medium subangular blocky structure; very friable, nonsticky and nonplastic; common very fine and fine roots; common medium distinct dark grayish brown (2.5Y 4/2) redoximorphic depletions; very strongly acid (pH 4.8); clear wavy boundary. (4 to 20 inches thick)
2Bg--18 to 26 inches; dark grayish brown (2.5Y 4/2) gravelly loam; weak coarse subangular blocky structure; friable, slightly sticky and slightly plastic; 20 percent subangular gravel and 5 percent subangular cobble; common medium distinct strong brown (7.5YR 4/6) redoximorphic concentrations; strongly acid (pH 5.2); gradual wavy boundary. (4 to 12 inches thick)
2C1--26 to 38 inches; dark grayish brown (2.5Y 4/2) very gravelly sandy loam; massive; friable, slightly sticky and slightly plastic; 40 percent subangular gravel; strongly acid (pH 5.4); diffuse irregular boundary. (10 to 22 inches thick)
2C2--38 to 60 inches; olive gray (5Y 4/2) very gravelly sandy loam; massive; friable, slightly sticky and slightly plastic; 40 percent subangular gravel and 5 percent subangular cobbles; strongly acid (pH 5.4).
TYPE LOCATION: Susitna Valley Area, Alaska; about 4 miles north of Trapper Creek; the NE 1/4 of the NE 1/4 of section 7, T. 26N., R. 5W., Seward Meridian.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature: 33 to 37 degrees F.
Depth to glacial till material: 14 to 33 inches
Loess mantle: dominated by volcanic ash; moist bulk density assumed at less than 0.9 grams per cubic centimeter: phosphorous retention greater than 85 percent
A horizon:
Matrix color: value of 2 or 3; chroma moist of 1 to 3
Texture: mucky silt loam, silt loam
Organic carbon: 6 to 12 percent
Reaction class: very strongly acid or strongly acid
Bg horizon:
Matrix color: hue of 10YR or 2.5Y; value of 3 or 4; chroma of 2 or 3
Texture: silt loam, very fine sandy loam
Reaction class: very strongly acid or strongly acid
2Bg horizon:
Matrix color: hue of 10YR or 2.5Y; value of 3 or 4; chroma of 2 or 3
Texture: sandy loam, fine sandy loam, loam modified by 20 to 40 percent total coarse fragments; 10 to 40 percent subangular gravel and 0 to 10 percent subangular cobbles
Reaction class: very strongly acid or strongly acid
2C horizon:
Matrix color: hue of 10YR to 5Y; value of 4 or 5; chroma of 1 or 2
Texture sandy loam, fine sandy loam modified by 35 to 50 percent total coarse fragments; 25 to 40 percent subangular gravel and 0 to 25 percent subangular cobbles
Reaction class: strongly acid or moderately acid
COMPETING SERIES: There are no competing series in this classification.
GEOGRAPHIC SETTING:
Parent material: volcanic ash influenced loess over gravelly glacial till deposits
Landform: depressions on till plains, depressions on hill, and depressions on mountains
Slopes: 0 to 20 percent
Mean annual temperature: about 33 degrees F.
Mean annual precipitation: about 28 inches
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Talkeetna and
Tokositna soils. Both soils are well drained.
DRAINAGE AND PERMEABILITY: Very poorly or poorly drained. Runoff is rapid. Saturated hydraulic conductivity is moderately high to high in the solum and moderately low to moderately high in the substratum.
USE AND VEGETATION: This soil is used primarily as wildlife habitat. Native vegetation is dominantly paper birch, white spruce and bluejoint reedgrass.
DISTRIBUTION AND EXTENT: Cook Inlet Lowlands MLRA 224, South-central Alaska. The series is of moderated extent.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: WASILLA, ALASKA
SERIES ESTABLISHED: Matanuska-Susitna Area, Alaska, 1996.
REMARKS: Diagnostic horizons and features recognized in this profile include: Redoximorphic depletions within 9 inches of the surface
Bulk density: upper part of the control section is assumed less than 0.9 g/cc
Lower part of the control section: loamy-skeletal
Temperature regime: cryic
Moisture regime: aquic
National Cooperative Soil Survey
U.S.A.