LOCATION SUSIVAR                 AK

Established Series
Rev. MHC/JPM/DM
02/2022

SUSIVAR SERIES

The Susivar series consists of very deep, somewhat poorly drained soils formed in stratified loamy alluvium more than 40 inches thick, underlain by very gravelly sand. Susivar soils are on floodplains and low stream terraces. Slopes range from 0 to 3 percent. The mean annual temperature is about 34 degrees F., and the average annual precipitation is about 25 inches.

TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, nonacid Typic Cryaquents

TYPICAL PEDON: Susivar silt loam -- on a 1 percent slope under native vegetation. (All colors are for moist soil)

Oi--0 to 2 inches; very dark brown (10YR 2/2) slightly decomposed plant material; strongly acid (pH 5.2); clear smooth boundary. (0 to 4 inches thick)

A--2 to 5 inches; very dark brown (10YR 2/2) silt loam; moderate fine granular structure; very friable, nonsticky and nonplastic; many very fine and fine and few medium roots; moderately acid (pH 5.6); clear smooth boundary. (1 to 4 inches thick)

ACg--5 to 11 inches; very dark brown (10YR 2/2) and dark greenish gray (5GY 4/1) silt loam stratified with few lenses of very fine and fine sand; moderate medium subangular blocky structure; very friable, nonsticky and nonplastic; common very fine and fine roots; common medium distinct strong brown redoximorphic concentrations; moderately acid (pH 5.6); clear smooth boundary. ( 0 to 11 inches thick)

Cg1--11 to 27 inches; olive gray (5Y 4/2) and dark brown (10YR 3/3) stratified fine sand, very fine sand and silt; massive; very friable, nonsticky and nonplastic; few very fine roots; common medium prominent reddish brown (5YR 4/4) redoximorphic concentrations; moderately acid (pH 5.6); clear smooth boundary. (8 to 27 inches thick)

Cg2--27 to 39 inches; reddish brown (5YR 4/4) stratified very fine sand and silt; massive; very friable, nonsticky and nonplastic; common large prominent dark greenish gray (5GY 4/1) redoximorphic depletions; moderately acid (pH 5.8); gradual smooth boundary. (0 to 15 inches thick)

C3--39 to 60 inches; dark brown (10YR 3/3) stratified fine sand, very fine sand and silt; massive; very friable, nonsticky and nonplastic; few medium distinct strong brown (7.5YR 4/6) redoximorphic concentrations; moderately acid (pH 5.8).

TYPE LOCATION: Matanuska-Susitna Valley Area, Alaska; about one mile south of the confluence of Kroto Creek and the Susitna River; in the NW 1/4 of the SW 1/4 of section 1, T.18 N., R.6 W., Seward Meridian.

RANGE IN CHARACTERISTICS: Mean annual soil temperature ranges from 33 to 36 degrees F. These soils are stratified with textures that include silt loam, loam, fine sandy loam, loamy fine sand, very fine sand, and fine sand. Depth to sands and gravel ranges from 40 to greater than 60 inches. Upon mixing, the control section is coarse-loamy. Organic carbon content varies irregularly with increasing depth. Reaction throughout the profile ranges from strongly acid to moderately acid.

The A horizon has hue of 10YR to 5Y; value of 3 or 4; and chroma of 1 to 3. Texture is stratified silt loam, fine sandy loam, and loamy fine sand.

The ACg and Cg horizons have hue of 5YR to 5GY; value of 3 to 6; and chroma of 1 to 4. These horizons have common to many greenish gray through red redoximorphic features present. The individual strata range from less than 1 inch to 18 inches in thickness.

The C horizons have hue of 10YR to 5Y; value of 3 or 4 and chroma of 1 to 4.

The 2C horizon (where present) is variegated sand and gravel. Coarse fragment content ranges from 40 to 70 percent; 10 to 20 percent cobbles, and 30 to 50 percent gravel.

COMPETING SERIES: These are the Aquatna, Moose River, and Noonku series. Aquatna, Moose River, and Noonku soils are very poorly drained.

GEOGRAPHIC SETTING: The Susivar soils are on floodplains and stream terraces. Slopes range from 0 to 3 percent. Susivar soils formed in stratified loamy alluvium more than 40 inches thick, underlain by very gravelly sand. The mean annual temperature is about 35 degrees F. and the average annual precipitation is 15 to 30 inches. Elevation ranges from 20 to 600 feet.

GEOGRAPHICALLY ASSOCIATED SOILS:

DRAINAGE AND PERMEABILITY: Somewhat poorly drained. Low to medium runoff. Moderate permeability in the upper horizons and rapid in the gravelly underlying material. Susivar soils are subject to flooding.

USE AND VEGETATION: Mostly forested. Dominant trees are balsam poplar, paper birch, and white spruce. Cleared areas are used for bromegrass, timothy, oats, barley, potatoes, and hardy vegetables.

DISTRIBUTION AND EXTENT: Cook Inlet-Susitna Lowlands, South Central, Alaska. The soil is extensive.

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

SERIES ESTABLISHED: Matanuska-Susitna Area. 1996.

REMARKS: Diagnostic features recognized in this profile include: no diagnostic horizons; mottles with chroma of two or less within 20 inches (50 centimeters) of the mineral soil surface; cryic temperature regime; coarse loamy particle size (weighted average) from 10 to 40 inches.

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National Cooperative Soil Survey
U.S.A.