LOCATION TUXEKAN            AK
Established Series
Rev. RWG/WDL/JPM
11/2002

TUXEKAN SERIES


The Tuxekan series consists of very deep, well drained soils that formed in alluvium on alluvial fans and terraces. Slopes range from 0 to 25 percent. Mean annual precipitation is about 120 inches, and mean annual temperature is about 45 degrees F.

TAXONOMIC CLASS: Coarse-loamy over sandy or sandy-skeletal, mixed, superactive Typic Humicryods

TYPICAL PEDON: Tuxekan silt loam - under conifer forest. (All colors are for moist soil.)

Oi--11 to 10-1/2 inches; undecomposed forest litter.

Oe--10-1/2 to 2 inches; very dusky red (2.5YR 2/2) mucky peat; many fine, medium, and coarse roots; extremely acid (pH 4.0); abrupt smooth boundary. (3 to 10 inches thick)

Oa--2 to 0 inches; black (N 2/0) muck; common fine and medium, few coarse roots; very strongly acid (pH 4.5); abrupt smooth boundary. (0 to 2 inches thick)

E--0 to 1 inch; dark gray (10YR 4/1) silt loam; weak fine subangular blocky structure; friable, slightly sticky, slightly plastic; 5 percent gravel; common fine and medium, few coarse roots; very strongly acid (pH 4.5); abrupt smooth boundary. (0 to 2 inches thick)

Bhs--1 to 3 inches; dark reddish brown (5YR 3/3 and 5YR 2.5/2) silt loam; weak fine subangular blocky structure; friable, slightly sticky,slightly plastic; 5 percent gravel; few fine, medium, and coarse roots; very strongly acid (pH 5.0); clear wavy boundary. (2 to 5 inches thick)

Bs--3 to 5 inches; dark yellowish brown (10YR 4/4) silt loam; weak fine subangular blocky structure; friable, slightly sticky,slightly plastic; 5 percent gravel; common fine and medium roots; strongly acid (pH 5.0); clear wavy boundary. (2 to 13 inches thick)

C1--5 to 16 inches; olive (5Y 5/3) loam; weak fine subangular blocky structure; very friable, slightly sticky, slightly plastic; 5 percent gravel; strongly acid (pH 5.5); clear wavy boundary. (5 to 12 inches thick)

2C2--16 to 60 inches; olive gray (5Y 4/2) extremely gravelly loamy sand; single grained; loose, nonsticky, nonplastic; 45 percent gravel, 15 percent cobbles; moderately acid (pH 5.8).

TYPE LOCATION: Hollis Area, Alaska. 4.5 miles from Thorne Bay on 2400 Road south side; SE 1/4, SE 1/4, SE 1/4, Sec. 13, T 71 S, R 83 E, Copper River Meridian.

RANGE IN CHARACTERISTICS: MAST ranges from 38 to 42 degrees F. Thickness of the solum ranges from 5 to 20 inches. Gravel content ranges from 0 to 25 percent in the solum and from 0 to 65 percent in the lower part of the control section. The mean annual soil temperature is 42 degrees F, and the mean summer soil temperature is 46 degrees F. Reaction ranges from extremely acid to slightly acid.

An A horizon may be present in some pedons.

The E horizon has hue ranging from 5YR to 10YR; value moist from 3 to 6; and chroma moist from 1 to 3. Texture is silt loam, fine sandy loam or loam with 0 to 30 percent coarse fragments.

The B horizon has hue ranging from 2.5YR to 10YR; value moist from 2 to 5; and chroma moist from 1 to 6. Texture is silt loam, loam, and very fine sandy loam, with 0 to 15 percent coarse fragments. Some pedons have fine sandy loam and sandy loam textures.

The 2C horizon has hue ranging from 10YR to 5Y. Texture includes loamy sand and sand. Coarse fragment content ranges from 0 to 65 percent, with 0 to 10 percent cobbles, and 0 to 55 percent gravel.

COMPETING SERIES: There are no known competing series.

GEOGRAPHIC SETTING: The Tuxekan soils occur on alluvial fans and stream terraces and are formed in mixed alluvium. The climate is humid maritime with mean annual precipitation of 100 to 160 inches. The mean annual temperature is 45 degrees F. The slope gradient is commonly less than 5 percent, but ranges from 0 to 15 percent. Elevation ranges from sea level to 1500 feet.

GEOGRAPHICALLY ASSOCIATED SOILS: These include the Karta, Kina, Kogish, Maybeso, Staney, and Tonowek, soils. The Tonowek soils lack a spodic horizon and are found on alluvial fans. The Karta and Wadleigh soils are formed in glacial till. The Kina, Kogish, Maybeso, and Staney soils are poorly drained organic soils.

DRAINAGE AND PERMEABILITY: Well drained. Moderate over rapid permeability. Slow runoff.

USE AND VEGETATION: The Tuxekan soils are used for timber production, watershed protection, recreation, and wildlife habitat. Overstory vegetation is dominantly Sitka spruce and western hemlock, with lesser amounts of western redcedar. Understory vegetation consists of blueberry and huckleberry, rusty menziesia, salmonberry, devilsclub, ladyfern, clubmosses, and other mosses.

DISTRIBUTION AND EXTENT: Southeast Alaska. The series is extensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon

SERIES ESTABLISHED: Hollis Area, Alaska, 1969.

REMARKS: Diagnostic horizons and features recognized in this soil are: a. albic horizon from 0 to 1 inch; a spodic horizon from 1 to 5 inches; more than 6 percent organic carbon in the upper 4 inches of the spodic horizon; coarse-loamy material from 10 to 16 inches and sandy-skeletal material from 16 to 40 inches. A cryic temperature regime is assumed.

The Tuxekan series formerly classified as medial over sandy or sandy-skeletal. That part of the spodic horizon that meets amorphous requirements does not extend more than 4 inches into the 10 to 40 inch control section. The particle size of the control section has a significant relation to the physical and chemical properties of the soil. The Tuxekan series is proposed as a benchmark soil series.

ADDITIONAL DATA: Laboratory data is available on this soil: NSSL Pedon number 78AK-130-002.


National Cooperative Soil Survey
U.S.A.