LOCATION STEMILT WA
Established Series
Rev. VB/RJE/TLA/RWL
09/2019
STEMILT SERIES
Landscape--mountains, plateaus, canyonlands
Landform--mountain slopes, structural benches, ridges, canyons
Slope--0 to 75 percent
Parent material--ash and loess over material derived dominantly from basalt or andesite and some sandstone
Mean annual precipitation--about 640 mm
Mean annual air temperature--about 7 degrees C
Depth class--very deep, deep
Drainage class--well drained
Soil moisture regime--xeric
Soil temperature regime--frigid
Soil moisture subclass--typic
TAXONOMIC CLASS: Loamy-skeletal, isotic, frigid Vitrandic Argixerolls
TYPICAL PEDON: Stemilt ashy silt loam, forested
O--0 to 3 cm; moderately decomposed organic litter of needles, twigs, and leaves
A--3 to 15 cm; ashy silt loam, dark grayish brown (10YR 4/2) dry, very dark grayish brown (10YR 3/2) moist; moderate thin platy structure; slightly hard, friable, slightly sticky and slightly plastic; many fine roots; many very fine tubular pores; 5 percent cobbles; NaF pH 8.8; neutral (pH 6.8); clear smooth boundary
AB--15 to 46 cm; ashy silt loam, brown (10YR 5/3) dry, dark brown (10YR 3/3) moist; weak fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; many fine roots; many very fine tubular pores; 10 percent cobbles and gravel; NaF pH 8.6; neutral (pH 6.8); clear wavy boundary
2Bt1--46 to 97 cm; very cobbly silty clay loam, brown (10YR 5/3) dry, dark yellowish brown (10YR 3/4) moist; moderate fine subangular blocky structure; hard, firm, moderately sticky and very plastic; common fine roots; many very fine tubular pores; 60 percent cobbles and gravel; few faint clay films in pores and very few faint clay films on surfaces of peds; neutral (pH 6.8); gradual wavy boundary
2Bt2--97 to 150 cm; very cobbly silty clay loam, pale brown (10YR 6/3) dry, dark yellowish brown (10YR 4/4) moist; massive; very hard, firm, very sticky and very plastic; 60 percent cobbles and gravel; few faint clay films in pores; few clay bridges between sand grains; neutral (pH 6.8)
TYPE LOCATION: Chelan County, Washington, along Stemilt Hill Road; about 180 m east and 150 m north of the southwest corner of section 13, T. 21 N., R. 20 E.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--7 to 8 degrees C
Soil moisture--usually moist, but dry 60 to 75 consecutive days in all parts between depths of 10 and 30 cm
Thickness of mollic epipedon--25 to 46 cm
Upper 50 cm of argillic horizon--averages 35 to 65 percent rock fragments and 18 to 35 percent clay
Depth to bedrock and thickness of solum--100 to 150 cm or more
Reaction--6.1 to 7.3
Base saturation--less than 75 percent in some part between depths of 25 and 75 cm
Upper 25 to 55 cm
*Moist bulk density--0.85 to 1.30 g/cm3
*Volcanic glass content--5 to 20 percent
*Acid oxalate aluminum plus one-half iron--0.4 to 1.0 percent
*15-bar water retention--5 to 10 percent (air-dried samples)
A horizon
Value--4 or 5 dry, 1 to 3 moist
Chroma--2 or 3 dry or moist
Texture of fine-earth fraction--ashy silt loam, ashy loam, ashy sandy loam
Gravel content--0 to 20 percent
Cobble content--0 to 5 percent
Stone content--0 to 30 percent
Thickness--5 to 30 cm
AB horizon, and Bw horizon (where present)
Value--4 or 6 dry
Chroma--2 to 4 moist or dry
Texture of fine-earth fraction--ashy silt loam, ashy sandy loam, ashy loam
Gravel content--5 to 45 percent
Cobble content--0 to 20 percent
Thickness of AB horizon--0 to 51 cm
2Bt horizon
Hue--10YR, 7.5YR
Value--4 to 6 dry, 3 or 4 moist
Chroma--2 to 6 dry or moist
Texture of fine-earth fraction--loam, sandy clay loam, silty clay loam, clay loam
Gravel content--15 to 55 percent
Cobble content--5 to 45 percent
Stone content--0 to 10 percent
Thickness of 2Bt1 horizon--25 to 61 cm
COMPETING SERIES:
Barneycreek--vitrandic material 18 to 25 cm thick
Getaway--mollic epipedon 50 to 90 cm thick
Klicker,
Larabee--50 to 100 cm (moderately deep) to a lithic contact (basalt)
Klickson,
Millerflat,
Ryespur--dry 45 to 60 consecutive days following summer solstice
Southworth--50 to 100 cm (moderately deep) to a lithic contact (shale)
Sycreek--90 to 115 cm (moderately deep, deep) to a densic contact
Wileyflat--50 to 100 cm (moderately deep) to a lithic contact (rhyolitic tuff)
GEOGRAPHIC SETTING:
Elevation--610 to 1650 m
Climate--warm, dry summers; moist, cold winters
Mean annual precipitation--410 to 1000 mm
Mean January air temperature--about -4 degrees C
Mean July air temperature--about 20 degrees C
Mean annual air temperature--about 4 to 8 degrees C
Frost-free season--70 to 125 days
Growing season (-2 degrees C)--145 to 170 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Anatone--25 to 50 cm (shallow) to a lithic contact (basalt); on plateaus and mountain slopes
Bocker--10 to 25 cm (very shallow) to a lithic contact (basalt); on plateaus and mountain slopes
Clint--mesic soil temperature regime; no argillic horizon; on mountain slopes
Colockum--mesic soil temperature regime; fine-loamy particle-size class; on mountain slopes
Loneridge,
Tekison--clayey-skeletal particle-size class; on mountain slopes
Tronsen--mesic soil temperature regime; clayey-skeletal particle-size class; on mountain slopes
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--well drained
Saturated hydraulic conductivity (Ksat)--moderately high
USE AND VEGETATION:
Use--livestock grazing, timber production, recreation, watershed
Native vegetation--ponderosa pine, Douglas-fir, pinegrass, arrowleaf balsamroot, elk sedge, bluebunch wheatgrass, Idaho fescue
DISTRIBUTION AND EXTENT: Central and north-central Washington; MLRA 6; moderate extent
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Chelan County, Washington; 1969
REMARKS:
Diagnostic horizons and other features recognized in this pedon
*Mollic epipedon--zone from 3 to 46 cm
*Argillic horizon--zone from 46 to 155 cm
*Vitrandic feature--zone from 3 to 46 cm
*Particle-size control section--zone from 46 to 96 cm
ADDITIONAL DATA:
Laboratory data--pedon numbers 90P722 and 92P019 (taxadjunct); National Soil Survey Laboratory, Lincoln, Nebraska
National Cooperative Soil Survey
U.S.A.