LOCATION STEVENS                 WA

Established Series
Rev. NCD-BDG-RJS
05/2017

STEVENS SERIES

The Stevens series consists of moderately deep (to a densic horizon), well drained soils that formed in glacial till of mixed mineralogy (including argillite, quartzite, and limestone), influenced by loess and volcanic ash. Stevens soils are on hills and hillslopes. Slopes are 0 to 65 percent. Average annual precipitation is about 450 mm, and the mean annual air temperature is about 8.3 degrees C.

TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Vitrandic Haploxerolls

TYPICAL PEDON: Stevens ashy silt loam - cultivated. (Colors are for dry soil unless otherwise noted.)

Ap--0 to 20 cm; dark gray (10YR 4/1) ashy silt loam, black (10YR 2/1) moist; weak fine and medium granular structure; soft, friable, slightly sticky and slightly plastic; many fine roots; 2 percent gravel; neutral (pH 6.8); abrupt smooth boundary. (13 to 23 cm thick)

A1--20 to 38 cm; dark grayish brown (10YR 4/2) silt loam, very dark brown (10YR 2/2) moist; weak medium prismatic structure that parts to weak medium subangular blocky; slightly hard, friable, slightly sticky and slightly plastic; many fine roots; few fine pores; 5 percent gravel; neutral (pH 6.6); clear wavy boundary. (10 to 23 cm thick)

A2--38 to 48 cm; dark grayish brown (10YR 4/2) silt loam, very dark brown (10YR 2/2) moist; weak fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many fine roots; common fine pores; 10 percent gravel; neutral (pH 6.8); gradual wavy boundary. (8 to 15 cm thick)

Bt--48 to 76 cm; brown (10YR 5/3) gravelly loam, dark brown (10YR 3/3) moist; moderate medium prismatic structure that parts to moderate medium subangular blocky; hard, friable, moderately sticky and moderately plastic; many fine roots; common fine pores; 15 percent gravel; faint patchy clay films on peds and in pores; common fine pores; neutral (pH 7.0); gradual wavy boundary. (18 to 30 cm thick)

BCt--76 to 96 cm; grayish brown (2.5Y 5/2) gravelly loam, dark grayish brown (2.5Y 4/2) moist; weak fine and medium subangular blocky structure; hard, friable, moderately sticky and moderately plastic; common fine roots; common fine pores; thin patchy clay films on peds and in pores; 30 percent gravel; neutral (pH 7.2); gradual wavy boundary. (13 to 25 cm thick)

Cd--96 to 152 cm; grayish brown (2.5Y 5/2) gravelly loam, dark grayish brown (2.5Y 4/2) moist; massive; hard, friable, moderately sticky and moderately plastic; few roots; many fine pores; 30 percent gravel; slightly effervescent; slightly alkaline (pH 7.8).

TYPE LOCATION: Stevens County, Washington; about 3.2 kilometers northeast of Barstow; 120 meters east and 150 meters north of the southwest corner of sec. 11, T. 38 N., R. 37 E. Latitude - 48 degrees, 48 minutes, 0 seconds north; Longitude - 118 degrees, 5 minutes, 0.46 seconds west; NAD83; USGS Bossburg Quadrangle.

RANGE IN CHARACTERISTICS:
Mean annual soil temperature at a depth of 50 cm -- 8.9 to 11.1 degrees C).
Soil Moisture -- usually moist but are dry in all parts between depths of 10 and 60 cm for 60 to 90 consecutive days following the summer solstice.
Mollic epipedon -- 50 to 100 cm thick
Depth to densic material -- 64 to 100 cm

Note: Base saturation (by sum of cations) - less than 75 percent in parts of the upper 75 cm of the soil

Vitrandic Feature
Thickness -- 18 to 35 cm
Moist bulk density - 1.15 to 1.35 g/cc
Volcanic glass content - 5 to 20 percent
Acid-oxalate extractable Al plus 1/2 of the acid-oxalate extractable Fe -- 0.4 to 1.0 percent
15-bar water retention -- 5 to 10 percent for air dried samples
Depth to calcium carbonate -- 64 to greater than 150 cm

Particle-size control section -- 5 to 30 percent coarse fragments.

Ap, A1, A2 horizons
Value: 3 to 5 dry; 2 or 3 moist
Chroma: 1 to 3 dry or moist
Texture (less than 2mm fraction): ashy silt loam (surface), silt loam
Clay content: 6 to 18 percent
Rock fragments: 0 to 30 percent--0 to 30 percent gravel; 0 to 8 percent cobbles
Reaction: pH 6.6 to 7.3

Bt, BCt, (Bw, BA where present) horizons
Hue: 10YR or 2.5Y dry or moist
Value; 4 to 6 dry; 3 to 5 moist
Chroma: 2 to 4 dry or moist
Texture (less than 2mm fraction): silt loam or loam
Clay content: 10 to 18 percent
Rock fragments: 8 to 30 percent--8 to 30 percent gravel; 0 to 3 percent cobbles
Reaction: pH 6.6 to 7.3
Note: The Bt and BCt horizons have thin patchy clay films on peds and in pores. However, the increase in clay is not sufficient to constitute an argillic horizon.


Cd (C where present) horizons
Hue: 10YR or 2.5Y dry or moist
Value: 4 to 7 dry; 3 to 5 moist
Chroma: 2 to 4 dry or moist
Texture (less than 2mm fraction): loam or sandy loam
Clay content: 8 to 18 percent
Rock Fragments: 15 to 35 percent--15 to 35 percent gravel; 0 to 5 percent cobbles
Reaction: pH 6.6 to 7.8

COMPETING SERIES:
Cabincreek (OR): are deep to a lithic contact
Conconully (WA): are dry 90 to 105 consecutive days in summer
Deno (WA): are deep to a lithic contact
Doublecreek (OR): do not have a densic horizon
Fanal (WA): do not have a densic horizon
Phoebe (WA): do not have a densic horizon
Safety (WA): are moderately deep to a paralithic contact
Uhlig (WA): do not have a densic horizon

GEOGRAPHIC SETTING: Stevens soils are have elevations of 455 to 1,200 meters. Slopes are 0 to 65 percent. These soils formed in glacial till of mixed mineralogy (including argillite, quartzite, and limestone), influenced by loess and volcanic ash. They occur on hills and hillslopes. They are in a continental climate. Mean annual temperature is 7.7 to 10.0 degrees C. Average annual precipitation is about 325 to 650 mm, and the frost-free season is 100 to 130 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cedonia, Dehart, Garrison, Hunters, Molcal, and Scoap soils and the competing Donavan soil. Cedonia and Hunters soils have a fine-silty control section. Dehart, Garrison, and Scoap soils have a loamy-skeletal control section. Molcal soils are calcareous and have a coarse-loamy control section.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; medium runoff; moderately high saturated hydraulic conductivity in the upper part and moderately low or low in the lower part.

USE AND VEGETATION: Used for timber production and grazing, alfalfa hay, grass-legume hay, and small grains are common crops. The native vegetation is ponderosa pine and Douglas-fir with an understory of common snowberry, pinegrass, blue wildrye, creeping Oregon-grape, Saskatoon serviceberry, spreading sweetroot, and white stoneseed. These areas are growing bluebunch wheatgrass, Idaho fescue, Sandberg bluegrass, prairie junegrass, rose and common snowberry.

DISTRIBUTION AND EXTENT: Northeastern Washington; Ferry and Stevens County. The series is of moderate extent. MLRA 43A.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana

SERIES ESTABLISHED: Stevens County, Washington, 1913.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon -- 0 to 76 cm (Ap, A1, A2, Bt horizons)
Cambic horizon -- 76 to 96 cm (BCt horizon)
Densic material -- 96 to 152 cm (Cd horizon)
Particle-size control section -- 25 to 96 cm (part of A1, A2, Bt, BCt horizons)

ADDITIONAL DATA: Laboratory data are available on this soil. Soil laboratory numbers; 69207-69212 and 69213-69218. Data supports classification change.

Taxonomic version: Keys to Soil Taxonomy, Twelfth Edition, 2014.

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National Cooperative Soil Survey
U.S.A.