LOCATION YENSUS                  AK

Established Series
Rev. MHC/JPM
02/2022

YENSUS SERIES

The Yensus series consists of very deep, well drained soils formed in loess deposits overlying coarse textured glaciofluvial sediments. Yensus soils are on glacial outwash plains, stream terraces and hillslopes. Slopes range from 0 to 45 percent. Mean annual temperature is about 35 degrees F. and the average annual precipitation is about 17 inches.

TAXONOMIC CLASS: Coarse-silty over sandy or sandy-skeletal, mixed, superactive Typic Haplocryepts

TYPICAL PEDON: Yensus silt loam - on a 16 percent slope under paper birch and white spruce forest at 550 feet elevation. (All colors are for moist soil)

Oe--1 inch to 0 inches; very dark brown (10YR 2/2) partially decomposed forest and grass litter. (1 to 3 inches thick)

A--0 to 2 inches; very dark grayish brown (10YR 3/2) silt loam; moderate fine granular structure; very friable, nonsticky and nonplastic; many roots of all sizes; few fine faint dark yellowish brown (10YR 4/6) mottles; moderately acid (pH 5.6); clear smooth boundary. (2 to 5 inches thick)

AC--2 to 7 inches; brown (10YR 4/3) and dark grayish brown (10YR 4/2) silt loam; weak medium subangular blocky structure; very friable, nonsticky and nonplastic; common very fine, fine and medium roots; common medium distinct strong brown (7.5YR 4/6) mottles; moderately acid (pH 5.8); clear wavy boundary. (4 to 12 inches thick)

Bw/C1--7 to 14 inches; brown (7.5YR 4/4) silt loam with patches of brown (10YR 4/3) comprising about 45 percent of the horizon; moderate coarse subangular blocky structure; very friable, nonsticky and nonplastic; common very fine, fine and medium roots; few fine faint dark grayish brown (10YR 4/2) mottles; moderately acid (pH 5.8); gradual wavy boundary. (5 to 18 inches thick)

Bw/C2--14 to 18 inches; dark yellowish brown (10YR 4/6) silt loam with patches of brown (10YR 4/3) comprising about 30 percent of the horizon; moderate coarse subangular blocky structure; very friable, nonsticky and nonplastic; few very fine fine and medium roots; few fine faint dark grayish brown (10YR 4/2) mottles; moderately acid (pH 5.8); clear wavy boundary. (0 to 11 inches thick)

Bwb--18 to 29 inches; dark yellowish brown (10YR 4/6) silt loam; weak coarse subangular blocky structure; very friable, nonsticky and nonplastic; few very fine, fine and medium roots; moderately acid (ph 6.0); gradual smooth boundary. (5 to 12 inches thick)

BCb--29 to 36 inches; brown (10YR 4/3) and dark brown (10YR 3/3) silt loam; weak coarse subangular blocky structure; very friable, nonsticky and nonplastic; few very fine and fine roots; slightly acid (pH 6.2); clear smooth boundary. (0 to 8 inches thick)

2C--36 to 60 inches; variegated extremely gravelly sand; single grain; loose, nonsticky and nonplastic; 45 percent rounded gravel and 15 percent rounded cobble; slightly acid (pH 6.4).

TYPE LOCATION: Approximately 3 miles NE of Palmer, Alaska; SE 1/4, SE 1/4, Section 11, T. 18 N., R 2 E., Seward Meridian.

RANGE IN CHARACTERISTICS: Mean annual soil temperature ranges from 33 to 36 degrees F. Depth to sand and gravel ranges from 24 to 40 inches. Texture of the loess mantle is silt loam with less than 18 percent clay and less than 15 percent fine sand or coarser. Reaction ranges from moderately acid to slightly acid in the loess cap and slightly acid or neutral in the substratum.

The A and AC horizons have moist hue from 10YR or 2.5Y; value moist from 2 through 4; and chroma moist of 2 or 3. Occasional thin strata of darker colors (buried O horizons and charcoal) occur throughout these horizons. Texture is silt loam or very fine sandy loam.

The buried Bw/C horizons have two dominant color groups. The Bw portion has hue of 7.5YR or 10YR; chroma moist from 4 through 6. The C portion has has hue from 10YR through 5Y; chroma moist of 1 or 2. Occasional thin strata of darker colors (buried O horizons and charcoal) occur throughout these horizons. Texture is silt loam or very fine sandy loam.

The Bwb horizon has hue of 7.5YR or 10YR; chroma moist from 4 to 6; Texture is silt loam or very fine sandy loam.

The BCb or C horizon has hue of 10YR or 2.5YR; value moist of 3 or 4; chroma moist of 3 or 4. Texture is silt loam or very fine sandy loam.

The 2C horizons have variegated colors. Textures include sand and coarse sand with 40 to 70 percent gravel and cobble.

COMPETING SERIES: These are the Gulkana, Nenana and Knik series in the same family. Gulkana soils have calcareous substratums. Nenana soils have substantial mica content. Knik soils have loess mantles thinner than 24 inches.

GEOGRAPHIC SETTING: The Yensus soils are on stream terraces outwash plains and hills. They formed in a loess mantle overlying glaciofluvial deposits of sand and gravel. The loess is dominantly glacial flour from active glacial outwash plains. The climate is transitional maritime-continental. Mean annual temperature is 35 degrees F. and mean annual precipitation is 17 inches.

GEOGRAPHICALLY ASSOCIATED SOILS:

DRAINAGE AND PERMEABILITY: Well drained. Slow to rapid runoff. Moderate permeability in the loess mantle and rapid in the underlying sand and gravel.

USE AND VEGETATION: Used for cropland, pasture, and wildlife habitat. The native vegetation includes white spruce and paper birch.

DISTRIBUTION AND EXTENT: Southcentral Alaska. The series is of moderate extent.

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

SERIES ESTABLISHED: Matanuska-Susitna Area, 1996.

REMARKS: Diagnostic horizons and features recognized in this profile include: ochric epipedon from 0 to 7 inches; cambic horizon from 7 to 29 inches; cryic temperature regime; weighted average of coarse silty particle size from 0 to 36 inches.

Yensus series incorporates those soils of the Telaquana series with loess mantles thicker than 24 inches. The thinner mantled Telaquana soils are included in the revised concept of the Knik series. Telaquana soils will be dropped.

---

National Cooperative Soil Survey
U.S.A.