LOCATION OSAR                    AK

Established Series
Rev. MHC/DLM
05/2022

OSAR SERIES

Depth class: very deep
Drainage class: poorly drained
Landforms: fan terraces on alluvial fans; fan terraces on alluvial fans on mountains
Parent material: silty eolian deposits over gravelly alluvium
Elevation: 2,667 to 2,930 feet (813 to 893 m)
Slope: 12 to 35 percent
Annual precipitation: 31 to 35 inches (776 to 886 mm)
Annual temperature: 25 degrees F (-4 degrees C)
Frost-free period: 60 to 80 days

TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, nonacid Humic Cryaquepts

TYPICAL PEDON: Osar mucky silt loam - on a slope of 55 percent under white spruce/willow woodland, wet. (All colors are for moist soil)

Oi--0 to 2 inches (0 to 5 cm); dark reddish brown (5YR 3/4) slightly decomposed plant material; many very fine, fine, medium, and coarse roots; very strongly acid (pH 4.8); abrupt wavy boundary.

A--2 to 10 inches (5 to 25 cm); dark brown (7.5YR 3/2) mucky silt loam; weak medium platy structure; very friable, nonsticky and nonplastic; common very fine, fine, and medium roots; very strongly acid (pH 5.0); abrupt irregular boundary.

2Bw--10 to 21 inches (25 to 53 cm); light olive brown (2.5Y 5/4) gravelly sandy loam; weak coarse subangular blocky structure; friable, nonsticky and nonplastic; few very fine and fine roots; 15 percent gravel, 2 percent cobbles; strongly acid (pH 5.5); gradual smooth boundary.

2C1--21 to 29 inches (53 to 74 cm); olive yellow (2.5Y 6/6) gravelly loam; massive; friable, nonsticky and nonplastic; 15 percent gravel, 5 percent cobbles; 10 mm yellowish brown (10YR 5/6) high chroma redox concentrations (approximately 40 percent of horizon); moderately acid (pH 5.8); gradual smooth boundary.

2C2--29 to 60 inches (74 to 152 cm); olive yellow (2.5Y 6/6) gravelly loam; massive; friable, nonsticky and nonplastic; 15 percent gravel, 5 percent cobbles; moderately acid (pH 5.8).

TYPE LOCATION: Delta River Area, Alaska; along the upper Delta River approximately 4.0 miles below Juneau Falls; UTM coordinates: Zone 6, Easting 558989, Northing 7007249.

RANGE IN CHARACTERISTICS:

Soil moisture class: aquic
Mean annual soil temperature: 33 to 35 degrees F (0.5 to 1.5 degrees C)
Mean summer soil temperature: 36 to 39 degrees F. (2 to 4 degrees C)
Depth to strongly contrasting textural stratification: 8 to 16 inches (20 to 40 cm)

Oi, Oe horizon:
Colorhue of 5YR to 10YR; value of 2 to 3; chroma of 1 to 4
Organic matter content65 to 90 percent
Reactionvery strongly acid or strongly acid

A horizon:
Colorvalue of 2 or 3; chroma of 1 to 3
Texturemucky silt loam or silt loam
Clay content0 to 10 percent
Silt content55 to 75 percent
Sand content15 to 35 percent
Organic matter content8 to 12 percent
Rock fragments0 to 5 percent subangular very strongly cemented gravel
Reactionvery strongly acid to moderately acid

2Bw horizon:
Colorhue of 10YR or 2.5Y; value of 3 to 5; chroma of 3 or 4
Texturegravelly loam, gravelly sandy loam or loam
Clay content0 to 10 percent
Silt content15 to 50 percent
Sand content30 to 75 percent
Organic matter content-2 to 6 percent
Rock fragments0 to 25 percent subangular very strongly cemented gravel; 0 to 10 percent subangular very strongly cemented cobbles
Reaction-very strongly acid to moderately acid

2C horizon:
Colorhue of 10YR to 5Y; value of 3 to 6; chroma of 2 to 6
Texturegravelly loam, gravelly sandy loam or loam
Clay content0 to 10 percent
Silt content15 to 50 percent
Sand content30 to 75 percent
Rock fragments0 to 25 percent subangular very strongly cemented gravel; 0 to 10 percent subangular very strongly cemented cobbles
Reaction-strongly acid or moderately acid

COMPETING SERIES: This is the Disappoint series. Disappoint series have a mean presumed annual soil temperature greater than 35 degrees F. (1.5 degrees C.).

GEOGRAPHIC SETTING:
Parent material: silty eolian deposits over gravelly alluvium
Elevation: 2,667 to 2,930 feet (813 to 893 m)
Slope: 12 to 35 percent
Annual precipitation: 31 to 35 inches (776 to 886 mm)
Annual temperature: 25 degrees F (-4 degrees C)
Frost-free period: 60 to 80 days

GEOGRAPHICALLY ASSOCIATED SOILS: These include Klute and Sonderna soils. Klute soils are well drained, very deep, and occur on flood plains and alluvial fans. Sonderna soils are well drained, very deep, and occur on terraces and alluvial fans.

DRAINAGE AND PERMEABILITY: Poorly drained, very high runoff. Saturated hydraulic conductivity is moderately high to high.

USE AND VEGETATION: Used for wildlife habitat and recreation. Native vegetation is white spruce/willow woodland, wet.

DISTRIBUTION AND EXTENT: MLRA 228, Interior Alaska Mountains, Alaska. The series is of small extent.

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

SERIES ESTABLISHED: Delta River Area, Alaska, 2005

REMARKS: Diagnostic features and horizons recognized in this profile include:
Umbric epipedon: 2 to 10 inches. (A horizon)
Cambic horizon: 10 to 21 inches. (2Bw horizon)
Redoximorphic concentrations: are masked by high organic matter content 2 to 10 inches. (A horizon)
Reaction to alapha, alapha-dipyridly: 2 to 10 inches. (A horizon)
Lithologic discontinuity: At the upper boundary of 2Bw horizon
Coarse-loamy particle size control section: 10 to 40 inches below the mineral soil surface
Temperature regime: cryic
Moisture regime: aquic.

ADDITIONAL DATA:

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National Cooperative Soil Survey
U.S.A.