LOCATION SHRUBCREEK WAInactive Series
TAXONOMIC CLASS: Ashy over loamy, amorphic over isotic, frigid Alfic Humic Vitrixerands
TYPICAL PEDON: Shrubcreek ashy fine sandy loam, on a 3 percent northwest-facing slope under coniferous vegetation. (Colors are for dry unless otherwise stated.)
Oi--0 to 1 inch; pine and fir needles and grass residue.
A1--1 to 3 inches; brown (7.5YR 5/2) ashy fine sandy loam, dark reddish brown (5YR 3/2) moist; moderate fine and medium granular structure; soft, very friable, nonsticky and nonplastic, weakly smeary; many very fine and fine roots; strongly acid (pH 5.5); clear wavy boundary. (2 to 10 inches thick)
A2--3 to 12 inches; brown (7.5YR 5/3) ashy fine sandy loam, dark brown (7.5YR 3/3) moist; weak medium subangular blocky structure parting to moderate medium granular; soft, very friable, nonsticky, nonplastic, weakly smeary; many very fine, fine, medium and common coarse roots; 10 percent gravel and 3 percent cobbles; moderately acid (pH 5.8); (NaF pH 11.0); clear wavy boundary. (6 to 15 inches thick)
Bw--12 to 17 inches; brown (10YR 5/3) ashy loam, dark brown (7.5YR 3/3) moist; weak and moderate medium subangular blocky structure; soft, very friable, nonsticky, nonplastic, weakly smeary; many very fine and fine, common medium and few coarse roots; 5 percent gravel and 5 percent cobbles; moderately acid (pH 5.9); (NaF pH 10.8); clear wavy boundary. (5 to 11 inches thick)
2Bt1--17 to 25 inches; brown (10YR 5/3) ashy loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; slightly hard, firm, slightly sticky and slightly plastic; common very fine and fine, few medium roots; few fine vesicular pores; common distinct clay films on faces of peds and in pore openings; 12 percent gravel; moderately acid (pH 5.8); (NaF pH 10.0); clear wavy boundary. (7 to 15 inches thick)
2Bt2--25 to 37 inches; brown (7.5YR 5/4) silt loam, dark brown (7.5YR 4/2) moist; moderate medium subangular blocky structure; slightly hard, firm, slightly sticky and slightly plastic; common very fine, fine and medium roots; few fine vesicular pores; common distinct clay films on faces of peds and in pore openings; 5 percent gravel; slightly acid (pH 6.1); (NaF pH 9.9); clear wavy boundary. (10 to 18 inches thick)
2Bt3--37 to 61 inches; brown (7.5YR 5/2) silt loam, dark reddish brown (5YR 3/2) moist; massive parting to moderate medium subangular blocky structure; slightly hard, firm, slightly sticky and slightly plastic; few very fine, fine and medium roots; few fine vesicular pores; common distinct clay films on faces of peds and in pore openings; 30 percent light gray (10YR 7/2) strongly weathered basalt paragravel; slightly acid (pH 6.3); (NaF pH 9.2).
TYPE LOCATION: Yakima County, Washington; about 3 miles northwest of Smith Butte, 1,528 feet west and 3,017 feet south of the northeast corner, sec. 36, T. 8 N., R. 15 E.
RANGE IN CHARACTERISTICS: Depth to diagnostic horizons and features are measured from the top of the first mineral layer. These soils are usually moist, but are dry in the moisture control section for 60 to 75 consecutive days following summer solstice. The mean annual soil temperature at 20 inches is 45 to 47 degrees F. The volcanic ash mantle is 14 to 30 inches thick. The soil is greater than 60 inches to bedrock. The upper part of the 0 to 40 inch particle-size control section has an estimated moist bulk density of 0.80 to 0.90 g/cc, volcanic glass content of 30 to 60 percent, acid oxalate extractable aluminum plus one-half iron of 1.0 to 2.0 percent, phosphate retention of 50 to 75 percent, and 15-bar water retention of 8 to 12 percent. The lower part has a clay content of 18 to 27 percent and rock fragment content of 5 to 15 percent.
The A horizon has a hue of 7.5YR or 10YR, value of 4 or 5 dry, 2 or 3 moist, and chroma of 2 or 3 dry and moist. The texture is ashy sandy loam, ashy fine sandy loam, and ashy loam that have 5 to 10 percent rock fragments. Field estimated clay content ranges from 5 to 10 percent. Reaction is moderately acid or strongly acid.
The Bw horizon has hue of 7.5YR or 10YR, value of 4 or 5 dry, 3 or 4 moist, and chroma of 3 or 4 dry and moist. Texture is ashy loam, ashy silt loam, or ashy fine sandy loam. Reaction is slightly acid or moderately acid.
The 2Bt horizon has a hue of 7.5YR or 10YR, value of 4 or 5 dry, 3 or 4 moist, and a chroma of 2, 3, or 4 dry or moist. Texture is loam or silt loam. Clay content ranges from 18 to 27 percent. Rock fragments range from 5 to 15 percent with 5 to 30 percent paragravel below 40 inches. Reaction is moderately acid or slightly acid.
COMPETING SERIES: There are no competing soils.
GEOGRAPHIC SETTING: Shrubcreek soils occur on ridges, plateaus and mountain side slopes at elevations of 3,400 to 4,500 feet. The average annual precipitation ranges from 22 to 30 inches and the average annual temperature is about 43 degrees F. The frost-free season is 90 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: Bocker, Dryfalls (T), Grandpon, and Yin (T) soils. Bocker soils are less than 14 inches to a lithic contact. Dryfalls soils are mesic. Grandpon soils have an ashy over loamy-skeletal particle-size control section and lack an argillic horizon. Yin soils have greater than 35 percent rock fragments in the particle-size control section.
DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderate.
USE AND VEGETATION: Dominant uses are for grazable woodland, woodland, wildlife habitat, and recreation. Native vegetation is ponderosa pine, Douglas-fir, and grand fir, with an understory of dwarf huckleberry, elk sedge, creambush oceanspray, needle grass, and western brackenfern.
DISTRIBUTION AND EXTENT: East slopes of the Cascade Mountains on the Yakima Indian Reservation, Yakima County, Washington. Series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES PROPOSED: Yakima County, Washington, 1987.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Umbric epipedon - the zone from 1 to 17 inches (A1, A2, and Bw horizons)
Argillic horizon - the zone from 17 to 61 inches (2Bt1, 2Bt2, and 2Bt3 horizons)
Andic soil properties - the zone from 1 to 17 inches
Particle-size control section - the zone from 1 to 41 inches with 1 to 17 inches qualifying as ashy and 17 to 41 inches qualifying as loamy.
Soil Moisture regime - xeric
This pedon reflects a reclassification as of 7/00 from fine-loamy, mixed, frigid Ultic Haploxeralfs to ashy over loamy, amorphic over isotic, frigid Alfic Humic Vitrixerands..
The amorphic and isotic mineralogy are based on lab data from associated soils and is believed to be caused by Mt. Adams influences.