LOCATION XENO WA
Established Series
Rev. RLE/RJE/TLA
06/2011
XENO SERIES
The Xeno series consists of deep, well drained soils formed in residuum and colluvium from highly weathered tuff and tuffaceous breccia with a mantle of volcanic ash and loess. They are on benches, mountainsides and broad ridgetops. Slopes are 5 to 90 percent. The mean annual precipitation is about 55 inches and the mean annual temperature is about 43 degrees F.
TAXONOMIC CLASS: Fine-loamy, isotic, frigid Andic Humudepts
TYPICAL PEDON: Xeno medial silt loam - in a clearcut of coniferous forest on a 55 percent, convex, south-west facing slope at 2,200 feet elevation. The soil was moist throughout when described. (Colors are for moist soil unless otherwise stated. All textures are apparent field textures.)
Oe--0 to 2 inches; moderately decomposed litter of leaves, twigs, bark and cones.
A1--2 to 5 inches; very dark brown (10YR 2/2) medial silt loam, dark brown (10YR 3/3) dry; weak very fine and fine granular structure; soft, very friable, slightly sticky and slightly plastic, weakly smeary; many very fine, fine, medium and coarse roots; many fine irregular pores; 10 percent shot-like aggregates (2-5mm in diameter); 5 percent subangular gravel; moderately acid (pH 5.6); clear wavy boundary.
A2--5 to 12 inches; very dark grayish brown (10YR 3/2) medial silt loam, brown (10YR 5/3) dry; moderate very fine and fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic, weakly smeary; many very fine, fine, medium and coarse roots; many fine irregular pores; 10 percent shot-like aggregates (2-5mm in diameter); 5 percent subangular gravel; moderately acid (pH 5.8); clear wavy boundary. (Combined thickness of the A horizon is 7 to 14 inches)
Bw1--12 to 20 inches; dark brown (10YR 3/3) silt loam, yellowish brown (10YR 5/4) dry; moderate medium subangular blocky structure parting to moderate fine subangular blocky; slightly hard, friable, slightly sticky and slightly plastic, weakly smeary; many very fine, fine, medium and coarse roots; many fine irregular pores; 5 percent shot-like aggregates (2-5mm in diameter); 10 percent subangular gravel and cobbles; moderately acid (pH 5.6); clear wavy boundary. (3 to 8 inches thick)
Bw2--20 to 26 inches; dark yellowish brown (10YR 4/4) silty clay loam, light yellowish brown (10YR 6/4) dry; moderate medium subangular blocky structure parting to moderate fine subangular blocky; hard, friable, slightly sticky and slightly plastic, weakly smeary; common very fine, fine, medium and coarse roots; many fine irregular pores; 5 percent angular and subangular tuff parafragments; strongly acid (pH 5.4); abrupt irregular boundary. (6 to 17 inches thick)
C1--26 to 40 inches; yellowish brown (10YR 5/8) very paragravelly silt loam, yellow (10YR 7/8) dry; massive; slightly hard, friable, slightly sticky and slightly plastic, weakly smeary; common fine, medium and coarse roots; common fine irregular pores; 40 percent angular paragravel tuff fragments; strongly acid (pH 5.4); abrupt irregular boundary. (10 to 18 inches thick)
C2--40 to 56 inches; light olive brown (2.5Y 5/4) and light yellowish brown (2.5Y 6/4) very paragravelly silt loam, pale yellow (2.5Y 7/4 and 2.5Y 8/4) dry; massive; slightly hard, friable, slightly sticky and slightly plastic, weakly smeary; few fine roots; few fine irregular pores; 50 percent angular and subangular paragravel tuff fragments; strongly acid (pH 5.2); clear irregular boundary. (10 to 18 inches thick)
Cr--56 to 66 inches; multicolored, highly weathered and fractured tuff with black manganese and iron staining and a few fine roots in the fractures.
TYPE LOCATION: Cowlitz County, Washington; about 1,980 feet north and about 2,310 feet east of the southwest corner section 36, T. 8 N., R. 1 E., W.M.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 44 to 46 degrees F. Depth to a paralithic contact with highly weathered tuff or tuffaceous breccia is 40 to 60 inches. The particle-size control section is 18 to 35 percent apparent clay and contains from 15 to 55 percent paragravel and paracobble fragments. Reaction ranges from slightly acid to strongly acid throughout. The umbric epipedon is 10 to 20 inches thick. The solum is 20 to 40 inches thick.
The A horizon has hue of 10YR or 7.5YR, value of 2 or 3 moist, 3 through 5 dry and chroma of 2 or 3 moist or dry. Rock fragments are in the upper part of some pedons. They are colluvial in origin and range from 5 to 30 percent.
The Bw hroizon has hue of 10YR through 5YR, value of 3 through 5 moist, 5 through 7 dry and chroma of 3 through 6 moist and dry. Texture is silt loam, gravelly silt loam, silty clay loam and gravelly silty clay loam. Gravel is 5 to 20 percent and cobbles are 0 to 5 percent.
The C horizon has hue of 2.5Y through 2.5YR, value of 4 or 5 moist, 5 through 8 dry and chroma of 4 through 8 moist and dry. The highly weathered tuff varies in color from pedon to pedon and is multicolored in some pedons. Texture is silt loam or silty clay loam. Paragravel and paracobbles range from 35 to 60 percent.
COMPETING SERIES: These are the
Beigle,
Hyas,
Jonas,
Lates,
Moe,
Murnen,
Vailton and Wilholt series. Beigle, Hyas, Jonas and Wilholt soils have 15 to 35 percent hard rock fragments in the particle-size control section. Lates soils are 20 to 40 inches deep to a lithic contact. Moe soils have 35 to 45 percent apparent clay in the Bw horizon. Murnen soils lack soft rock fragments in the particler-size control section. Vailton soils have 15 to 35 percent soft siltstone or sandstone fragments in the particle-size control section.
GEOGRAPHIC SETTING: Xeno soils are on benches, mountainsides and broad ridgetops at elevations of 1,800 to 2,800 feet. Slopes are 5 to 90 percent. These soils formed in residuum and colluvium from highly weathered tuff and tuffaceous breccia of Eocene age, with a mantle of volcanic ash and loess. The climate is marine and is characterized by hot, dry summers and cool, moist winters. The mean annual precipitation is 70 to 100 inches. The mean annual air temperature is 42 to 44 degrees F. The growing season (28 degrees F) is 140 to 190 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Gobar,
Pheeney,
Siouxon,
Sarazan and
Voight soils. Gobar soils are mesic. Pheeney soils are medial-skeletal and have a lithic contact at a depth of 20 to 40 inches. Siouxon soils are medial-skeletal and mesic. Sarazan soils formed in hard basaltic breccia and are medial-skeletal. Voight soils have an argillic horizon.
DRAINAGE AND PERMEABILITY: Well drained, slow to very rapid runoff; moderate permeability.
USE AND VEGETATION: Used mainly for timber production, wildlife habitat, watershed and recreation. Vegetation is mainly Douglas-fir, western hemlock, red alder, western redcedar, and bigleaf maple with an understory of vine maple, Oregon-grape, red huckleberry, western swordfern, Oregon oxalis, trailing blackberry, longtube twinflower, minerslettuce and redwood violet.
DISTRIBUTION AND EXTENT: West slopes of the Cascade Mountains in Cowlitz County, Washington; MLRA 3. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Cowlitz County, Washington, 1989.
REMARKS: Diagnostic horizons and features recognized in this pedon are;
umbric epipedon from 2 to 20 inches
cambic horizon from 20 to 26 inches
paralithic contact at 56 inches.
The upper 7 to 14 inches of the mineral soil has an estimated moist bulk density of less than 0.90 g/cc, volcanic glass content of less than 5 percent, acid-oxalate extractable aluminum plus one-half iron of more than 2 percent. Bulk density is more than 0.90 g/cc below 14 inches.
All depths to diagnostic horizons and features are measured from the top of the first mineral horizon.
National Cooperative Soil Survey
U.S.A.