LOCATION TAHKENITCH              OR

Established Series
Rev. FWG-DRT-WRP
06/2011

TAHKENITCH SERIES

The Tahkenitch series consists of deep, well drained soils that formed in colluvium and residuum weathered from sandstone. These soils are on uplands and have slopes of 3 to 75 percent. The mean annual precipitation is 70 inches, and the mean annual temperature is 52 degrees F.

TAXONOMIC CLASS: Coarse-loamy, isotic, mesic Typic Humudepts

TYPICAL PEDON: Tahkenitch loam - mixed forest. (Colors are for moist soil unless otherwise noted.)

Oi--0 to 1 inch; slightly decomposed litter of leaves, needles, twigs and roots.

A1--1 to 7 inches; very dark brown (10YR 2/2) loam, dark grayish brown (10YR 4/2) dry; moderate fine and very fine granular structure; soft, very friable, nonsticky and nonplastic; many fine and very fine roots; many fine and very fine irregular pores; 5 percent fine concretions; strongly acid (pH 5.5); clear wavy boundary. (4 to 8 inches thick)

A2--7 to 13 inches; very dark grayish brown (10YR 3/2) loam, brown (10YR 5/3) dry; moderate very fine and fine granular structure; slightly hard, very friable, nonsticky and nonplastic; many fine and very fine roots; many fine and very fine irregular pores; 10 percent concretions and gravel; strongly acid (pH 5.5); clear wavy boundary. (6 to 10 inches thick)

BA--13 to 20 inches; dark brown (10YR 3/3) loam, brown (10YR 5/3) dry; weak medium and fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common fine and medium roots; many fine irregular pores; 10 percent gravel; very strongly acid (pH 5.0); gradual smooth boundary. (0 to 10 inches thick)

Bw1--20 to 32 inches; yellowish brown (10YR 5/6) gravelly sandy loam, light yellowish brown (10YR 6/4) dry; moderate medium subangular blocky structure; hard, friable, nonsticky and nonplastic; common fine and medium roots; many fine irregular pores; 20 percent gravel; very strongly acid (pH 5.0); gradual smooth boundary. (10 to 20 inches thick)

Bw2--32 to 43 inches; yellowish brown (10YR 5/4) gravelly sandy loam, light yellowish brown (10YR 6/4) dry; weak fine subangular blocky structure; hard, friable, nonsticky and nonplastic; common fine roots; many fine irregular pores; 20 percent gravel; very strongly acid (pH 5.0); clear irregular boundary. (0 to 15 inches thick)

Cr--43 inches; weathered fractured sandstone.

TYPE LOCATION: Lane County, Oregon; located in the northwest 1/4 northeast 1/4, sec. 24, T. 19 S., R. 12 W.

RANGE IN CHARACTERISTICS: The soil is usually moist but is dry in all parts between depths of 8 and 24 inches for fewer than 45 consecutive days during the summer. The mean annual soil temperature is 53 degrees F. There are 5 to 30 percent partially weathered sandstone and siltstone gravel in the solum. The soil is 40 to 60 or more inches deep to weathered sandstone or siltstone. The particle-size control section is loam or sandy loam, and averages less than 18 percent clay and more than 15 percent sand coarser than very fine sand. Hue is 10YR or 7.5YR. The umbric epipedon is 10 to 20 inches thick. The soil is strongly acid or very strongly acid.

The A horizon has value of 2 or 3 moist, 4 or 5 dry, and chroma of 2 or 3.

The upper part of the Bw horizon has a value of 3 to 5 moist, and chroma of 3 to 6. It is loam, sandy loam, or gravelly sandy loam.

The lower part of the Bw horizon has value of 4 or 5 moist, 5 or 6 dry, and chroma of 4 to 6, with bright stains or variegated colors in the lower part. It is sandy loam or gravelly sandy loam, and averages 10 to 35 percent partially weathered rock fragments.

COMPETING SERIES: These are the Burton and Ferrelo series. Burton soils are 20 to 40 inches deep over bedrock. Ferrelo soils have a B horizon with firm reddish brown concretions and thin firm or very firm weakly cemented lenses.

GEOGRAPHIC SETTING: Tahkenitch soils are on hills at elevations of 100 to 1,200 feet. Slopes range from 3 to 75 percent. The soils formed in sandy colluvium weathered from Tyee and equivalent sandstone. The marine climate has a short dry season during the summer. The mean annual precipitation is from 60 to 80 inches. The mean January temperature is 43 degrees F; the mean July temperature is 56 degrees F; and the mean annual temperature is 51 to 53 degrees F. The frost-free period is 185 to 240 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bohannon, Milbury, and Preacher soils. Bohannon and Preacher soils are fine-loamy. Lint soils are on terraces. Milbury soils are loamy-skeletal.

DRAINAGE AND PERMEABILITY: Well drained; medium or rapid runoff; moderate permeability.

USE AND VEGETATION: Primarily for production of timber and for wildlife habitat and water supply purposes. Native vegetation is Douglas-fir, western hemlock, red alder, vine maple, huckleberries, salal, and western swordfern.

DISTRIBUTION AND EXTENT: Coast range of the middle and southern Oregon Coast; MLRA 1. The series is not extensive.

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

SERIES ESTABLISHED: Lane County Area, Oregon, 1981

REMARKS: Diagnostic horizons and other features are;
Umbric epipedon from 1 to 20 inches
Cambic horizon from 13 to 43 inches

ADDITIONAL DATA: Lane County determined the engineering characteristics of two horizons sampled in Douglas County.

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National Cooperative Soil Survey
U.S.A.