LOCATION XANADU OREstablished Series
TAXONOMIC CLASS: Fine, kaolinitic, mesic Typic Palehumults
TYPICAL PEDON: Xanadu gravelly loam, on a south-facing planar slope of 7 percent under a coniferous forest at an elevation of 900 feet. (Colors are for moist soil unless otherwise stated.)
Oi--3 inches to 0; partially decomposed fir needles, leaves and twigs.
A1--0 to 4 inches; dark brown (7.5YR 3/2) gravelly loam, brown (7.5YR 5/4) dry; moderate very fine and fine granular structure; soft, friable, slightly sticky and slightly plastic; many very fine and fine, and common medium roots; many fine and medium irregular pores; common thin organic coatings lining pores and on faces of peds; 30 percent gravel; moderately acid (pH 6.0); clear smooth boundary. (3 to 5 inches thick)
A2--4 to 8 inches; dark brown (7.5YR 3/2) gravelly loam, brown (7.5YR 5/4) dry; moderate fine and medium granular structure; soft, friable, slightly sticky and slightly plastic; many very fine and fine, and common medium roots; many fine and medium irregular pores; few thin organic coatings lining pores and on faces of peds; 30 percent gravel; moderately acid (pH 5.8); clear smooth boundary. (3 to 6 inches thick)
BAt--8 to 15 inches; dark reddish brown (5YR 3/4) clay loam, yellowish red (5YR 5/6) dry; moderate medium and coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine, and few medium roots; common very fine and fine, and few medium tubular pores; few faint clay films lining pores; few thin organic coatings lining pores and on faces of peds; 5 percent gravel; strongly acid (pH 5.4); clear smooth boundary. (4 to 10 inches thick)
Bt1--15 to 28 inches; reddish brown (5YR 4/4) clay, yellowish red (5YR 5/6) dry; moderate medium and coarse subangular blocky structure; soft, friable, slightly sticky and slightly plastic; common very fine and fine, and few medium roots; common very fine and fine, and few medium tubular pores; common faint clay films on faces of peds and lining pores; 5 percent gravel; strongly acid (pH 5.4); gradual smooth boundary. (10 to 15 inches thick)
Bt2--28 to 45 inches; dark red (2.5YR 3/6) clay, yellowish red (5YR 5/8) dry; moderate medium and coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine and fine roots; few very fine tubular pores; common faint clay films on faces of peds and lining pores; 5 percent gravel; strongly acid (pH 5.4); gradual smooth boundary. (12 to 20 inches thick)
BCt--45 to 60 inches; dark red (2.5YR 3/6) clay, yellowish red (5YR 5/8) dry; weak medium and coarse subangular blocky structure; soft, friable, slightly sticky and slightly plastic; few very fine and fine roots; common very fine and fine tubular pores; few faint clay films on faces of peds and lining pores; 5 percent gravel; strongly acid (pH 5.4).
TYPE LOCATION: Douglas County, Oregon; 0.4 mile northwest of the confluence of Tip Davis Creek and Smith River; 2,460 feet south and 2,050 feet west of the NE corner of section 1, T. 21 S., R. 6 W. (Latitude 43 degrees, 46 minutes, 25 seconds N; Longitude 123 degrees, 21 minutes, 17 seconds W)
RANGE IN CHARACTERISTICS: Thickness of the solum commonly is 60 inches or more but is as thin as 40 inches in some pedons. The mean annual soil temperature is 47 to 55 degrees F. The soil is usually moist and is dry between 4 and 12 inches for less than 45 consecutive days during the summer. The argillic horizon is clay or clay loam and averages 35 to 55 percent clay with an apparent field texture of silt loam.
The A horizon has hue of 7.5YR or 5YR, value of 2 or 3 moist and 3 to 5 dry, chroma of 2 or 3 moist and 3 to 5 dry. Rock fragments range from 15 to 35 percent gravel.
The Bt horizon has hue of 5YR or 2.5YR, value of 3 or 4 moist, 4 to 6 dry, and chroma of 4 to 6 moist and 4 to 8 dry. It is clay or clay loam averaging 40 to 60 percent clay. Rock fragments range from 0 to 10 percent gravel.
The BAt horizon has hue of 7.5YR or 5YR, value of 3 or 4 moist, 4 to 6 dry and chroma of 3 to 6 moist and dry. Rock fragments range from 0 to 10 percent.
COMPETING SERIES: There are no other series in this family.
GEOGRAPHIC SETTING: Xanadu soils are on benches, broad ridgetops and mountain side slopes. Elevations are 200 to 2,500 feet. They formed in residuum and colluvium derived dominantly from siltstone and sandstone. Slopes range form 3 to 60 percent. The climate is characterized by warm, wet winters and hot, moist summers. The mean annual temperature is 45 to 53 degrees F. and the mean annual precipitation is 55 to 90 inches. The frost-free season is 145 to 240 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bohannon, Digger, Honeygrove, McDuff, Orford, and Preacher soils. Bohannon and Preacher soils are fine-loamy and do not have argillic horizons. McDuff soils are moderately deep to weathered siltstone and sandstone. Digger soils are in the loamy-skeletal family. Honeygrove and Orford soils have mixed mineralogy.
DRAINAGE AND PERMEABILITY: Well drained; moderately slow permeability.
USE AND VEGETATION: This soil is used for timber production and wildlife habitat. A few areas are used for pasture. The native vegetation includes Douglas fir, western hemlock, western redcedar, grand fir, red alder and bigleaf maple. The understory vegetation is mainly salal, vine maple, creambush oceanspray, western swordfern, cascade Oregongrape, red and evergreen huckleberry, and Pacific rhododendron.
DISTRIBUTION AND EXTENT: Coast Range of southwest Oregon; MLRA 1. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Douglas County, Oregon, 1994.
REMARKS: This draft reflects a change in classification from Haplohumults to Palehumults based on no decrease in clay from the maximum within the argillic to 60 inches.
Diagnostic horizons or features recognized in this pedon are:
Argillic horizon - The zone from 8 to 60 inches (BAt, Bt1, Bt2 and BCt horizons).
Humults feature - greater than 0.9 percent organic carbon in the upper 15 cm of the argillic horizon.
Kaolinitic mineralogy - apparent field textures are silt loam with lab data supporting clay loam or clay textures.
ADDITIONAL DATA: NSSL reference samples S80-OR-019-004, S81-OR-019-003, and S82-OR-019-003.