LOCATION TETHRICK OREstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Typic Dystroxerepts
TYPICAL PEDON: Tethrick gravelly fine sandy loam - on a northwest-facing concave slope of 50 percent under mixed conifers at 2,800 feet elevation. When described, the soil was moist throughout. (Colors are for moist soil unless otherwise stated.)
Oi--1/2 inch to 0; duff layer of fir needles, leaves, twigs and bark.
A1--0 to 4 inches; very dark grayish brown (2.5Y 3/2) gravelly fine sandy loam, light brownish gray (2.5Y 6/2) dry; moderate fine granular structure; slightly hard, very friable, nonsticky and nonplastic; many fine and very fine roots; many pores; 20 percent fine gravel; slightly acid; abrupt smooth boundary. (3 to 8 inches thick)
A2--4 to 9 inches; very dark grayish brown (2.5Y 3/2) gravelly fine sandy loam, light brownish gray (2.5Y 6/2) dry; moderate fine granular and moderate fine subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; many fine and very fine roots; many pores; 15 percent fine gravel; slightly acid; clear smooth boundary. (2 to 10 inches thick)
Bw1--9 to 15 inches; dark grayish brown (2.5Y 4/2) fine sandy loam, light brownish gray (2.5Y 6/2) dry; weak fine subangular blocky structure; slightly hard, very friable, slightly sticky and nonplastic; common fine roots; common fine and very fine tubular pores; 10 percent fine gravel; slightly acid; clear smooth boundary. (0 to 10 inches thick)
Bw2--15 to 30 inches; dark grayish brown (2.5Y 4/2) fine sandy loam, light brownish gray (2.5Y 6/2) dry; weak coarse subangular blocky structure; hard, friable, slightly sticky and nonplastic; few fine and medium roots; common very fine tubular pores; 5 percent fine weathered rock fragments; slightly acid; gradual wavy boundary. (10 to 30 inches thick)
C--30 to 53 inches; olive (5Y 4/3) fine sandy loam, light brownish gray (2.5Y 6/2) dry; massive; hard, friable, slightly sticky and nonplastic; common very fine tubular pores; 5 percent fine weathered rock fragments; slightly acid; gradual wavy boundary. (20 to 30 inches thick)
Cr--53 inches; grus from quartz diorite.
TYPE LOCATION: Josephine County, Oregon; about 4 miles southwest of Williams; 1,940 feet north and 380 feet west of the southeast corner of sec. 21, T. 39 S., R. 5 W.
RANGE IN CHARACTERISTICS: Solum thickness typically is 28 to 42 inches and ranges from 22 to 45 inches. Depth to a paralithic contact is 40 to over 60 inches. The mean annual soil temperature is 47 to 54 degrees F. These soils are usually moist, but are dry between depths of 8 and 24 inches for 60 to 90 consecutive days in the four months that follow the summer solstice. The 10- to 40-inch control section averages 5 to 15 percent gravel and 0 to 5 percent cobbles. The control section has 5 to 18 percent clay and more than 15 percent coarser than very fine sand.
The A horizon has hue of 2.5Y or 10YR, value of 3 through 6 moist, 5 through 7 dry, and chroma of 2 or 3 moist and dry.
The Bw horizon has hue of 10YR, 2.5Y or 5Y, value of 4 through 7 moist, 5 through 8 dry, and chroma of 2 through 6 moist and dry. It is fine sandy loam, sandy loam or loam.
The C horizon has hue of 10YR, 2.5Y or 5Y, value of 4 through 7 moist, 5 through 8 dry and chroma of 2 through 6 moist and dry. It is fine sandy loam, sandy loam or loam.
COMPETING SERIES: These are the Chaix, Dome, Elwha, Gilligan, Loper, Siskiyou, Steinmetz, Ulricher and Vader series. Chaix, Elwha, Loper and Siskiyou soils are 20 to 40 inches to bedrock. Dome soils are dry for over 90 consecutive days during the summer. Gilligan soils are dry for 45 to 60 consecutive days and have a silt loam mantle which extends into the upper part of the particle-size control section. Steinmetz soils are dry for 45 to 60 consecutive days. Ulricher soils are typically gravelly or cobbly in the B horizon and hue is 10YR throughout. Vader soils are dry for 45 to 60 consecutive days and are moderately to very strongly acid throughout.
GEOGRAPHIC SETTING: Tethrick soils are on mountain slopes at elevations of 700 and 4,000 feet and have slopes of 35 to 90 percent. The soils formed in colluvium weathered from quartz diorite or gabbro. The mean annual temperature is 45 to 53 degrees F. The mean annual precipitation is 35 to 60 inches. The frost-free period is 100 to 200 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Josephine, Lettia, Rogue, Selmac, Siskiyou and Wolfpeak soils. Josephine, Lettia, Selmac and Wolfpeak soils have an argillic horizon. Rogue soils have frigid soil temperature regime. Siskiyou soils are 20 to 40 inches deep to a paralithic contact.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Tethrick soils are used for timber production, water supply and wildlife habitat. Natural vegetation dominantly is Douglas fir, ponderosa pine, Pacific madrone, California black oak, golden chinkapin, cascade Oregongrape and common snowberry.
DISTRIBUTION AND EXTENT: Southwestern Oregon. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Josephine County, Oregon, 1979.
REMARKS: Formerly classified as coarse-loamy, mixed, mesic Dystric Xerochrepts, competing series not updated at the time of reclassification.
ADDITIONAL DATA: Complete characterization data and two engineering samples (A1 and A2 0-9 inches and Bw2 15-30 inches) for one pedon (S75Oreg. 17-1) by Oregon State University (unpublished).