LOCATION ERAKATAK OR+NV
Established Series
Rev. ARW-TM-JVC-JBF
02/2025
ERAKATAK SERIES
Landscape--mountains, foothills, lava plateaus
Landform--hillslopes, lava plateaus, mountain slopes, volcanic fields
Slope--0 to 80 percent
Parent material--residuum and colluvium derived from volcanic rock with an influence of volcanic ash in the surface
Mean annual precipitation--about 350 mm
Mean annual air temperature--about 6 degrees C
Depth class--moderately deep to lithic bedrock
Drainage class--well drained
Soil moisture regime--xeric
Soil temperature regime--frigid
Soil moisture subclass-typic
The Erakatak series consists of moderately deep, well drained soils that formed in residuum and colluvium derived from volcanic rocks with surface mantles of volcanic ash. Erakatak soils are on plateaus, hills, and mountains. Slopes are 2 to 80 percent. The mean annual precipitation is about 400 mm and the mean annual temperature is about 6 degrees C.
TAXONOMIC CLASS: Clayey-skeletal, smectitic, frigid Vitrandic Argixerolls
TYPICAL PEDON: Erakatak very cobbly ashy loam--rangeland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 5 cm; grayish brown (10YR 5/2) very cobbly ashy loam, dark brown (10YR 3/3) moist; moderate medium granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine, common fine, and few medium roots; common very fine, common fine, and few medium interstitial pores; 20 percent gravel, 15 percent cobbles, and 5 percent stones; neutral (pH 6.6); clear smooth boundary. (5 to 13 cm thick)
A2--5 to 18 cm; brown (10YR 5/3) very cobbly ashy loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure parting to moderate medium granular; slightly hard, friable, slightly sticky and slightly plastic; common very fine, common fine, and common medium roots; common very fine, common fine, and few medium interstitial pores; 15 percent gravel, 15 percent cobbles, and 5 percent stones; neutral (pH 6.8); abrupt smooth boundary. (10 to 20 cm thick)
Bt1--18 to 41 cm; brown (10YR 5/3) very cobbly ashy clay loam, dark brown (10YR 3/3) moist; strong medium angular blocky structure parting to moderate fine angular blocky; hard, firm, moderately sticky and moderately plastic; few very fine, common fine, common medium, and few coarse roots; few very fine, common fine, and few medium tubular pores; common distinct clay films on faces of peds; 20 percent gravel, 15 percent cobbles, and 5 percent stones; neutral (pH 7.0); clear wavy boundary. (13 to 38 cm thick)
Bt2--41 to 64 cm; light yellowish brown (10YR 6/4) very cobbly clay, dark yellowish brown (10YR 4/4) moist; moderate medium prismatic structure parting to moderate medium angular blocky; very hard, very firm, very sticky and very plastic; few very fine through coarse roots; few fine, few medium, and few coarse tubular pores; common prominent clay films on faces of peds; 25 percent gravel and 20 percent cobbles; neutral (pH 7.2); clear smooth boundary. (18 to 56 cm thick)
R--64 cm; fractured welded tuff.
TYPE LOCATION: Harney County, Oregon; about 0.5 miles north of Emigrant Creek; approximately 580 meters north and 305 meters east of the southwest corner of section 20, T. 20 S., R. 29 E.; USGS Hughet Valley 7.5 minute topographic quadrangle; WGS84 Decimal Degrees 43.8218680 latitude, -119.2732830 longitude. (Unknown how coordinates determined)
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--6 to 8 degrees C.
Soil moisture--Usually moist in the moisture control section in winter and spring, dry late July through late October; xeric soil moisture regime that borders on aridic.
Mollic epipedon--20 to 48 cm; includes the Bt1 horizon in some pedons.
Argillic horizon--25 to 85 cm
Depth to lithic contact--50 to 100 cm to a lithic contact.
Thickness of ash influenced layers--18 to 50 cm
Estimated properties of layers influenced by volcanic ash:
*Ammonium oxalate extractable Al + 1/2 Fe--0.2 to 0.4 percent
*0.02 to 2.0 mm fraction--30 to 70 percent
*Glass content in 0.02 to 2.0-mm fraction--5 to 60 percent
*1/3-bar bulk density--0.9 to 1.3 g/cm3
Particle-size control section:
*Clay--35 to 55 percent
*Total fragments--35 to 60 percent, mainly volcanic rocks such as tuff or basalt
A horizons
*Hue--10YR
*Value--4 or 5 dry, 2 or 3 moist
*Chroma--1 through 3, dry or moist
*Fine-earth texture--ashy sandy loam, ashy loam, ashy clay loam
*Clay--10 to 35 percent
*Sand--25 to 70 percent
*Organic matter--1 to 5 percent
*Total fragments--5 to 80 percent
*Gravel--5 to 35 percent
*Cobble--0 to 35 percent
*Stone--0 to 25 percent
*Boulder--0 to 20 percent
*Reaction--pH 6.6 to 7.8 (neutral to slightly alkaline)
Bt1 horizon
*Hue--10YR or 7.5YR
*Value--4 or 5 dry, 2 or 3 moist
*Chroma--2 through 4, dry or moist
*Fine-earth texture-- ashy clay loam, ashy silty clay loam, clay loam, silty clay loam, clay
*Clay--30 to 60 percent
*Sand--15 to 40 percent
*Organic matter--0.5 to 2 percent
*Total fragments--35 to 80 percent
*Gravel--5 to 40 percent
*Cobble--5 to 40 percent
*Stone--0 to 25 percent
*Reaction--pH 6.6 to 7.8 (neutral to slightly alkaline)
*Volcanic glass--some pedons have sufficient glass in the Bt1 to meet vitrandic subgroup
Bt2 horizon
*Hue--10YR or 7.5YR
*Value--4 through 6 dry, 2 through 4 moist
*Chroma--2 through 4, dry or moist
*Fine-earth texture--clay
*Clay--40 to 60 percent
*Sand--15 to 40 percent
*Organic matter--0.25 to 1 percent
*Total fragments--35 to 60 percent
*Gravel--5 to 40 percent
*Cobble--5 to 40 percent
*Stone--0 to 25 percent
*Reaction--pH 6.6 to 7.8 (neutral to slightly alkaline)
*Other features--Some pedons have pressure cutans in at least one of the Bt horizons; some pedons have relict redox concentrations of iron in the Bt2 horizon; some pedons have coats of opaline silica.
COMPETING SERIES:
DUPRATT--has Oi horizon, mollic epipedon greater than 50 cm thick
FINSEL--mollic epipedon thicker than 50 cm
HAMTAH--deeper than 100 cm to restrictive feature
HOME CAMP--50 to 100 cm to paralithic contact
HUMAREL--deeper than 100 cm to restrictive feature
LAMULITA--deeper than 100 cm to restrictive feature
MAULE--has Oi horizon; moisture control section is dry 60 to 90 days
MENBO--mollic epipedon thicker than 50 cm
ROYST--paralithic contact above the lithic contact, moisture control section is dry less than 100 days
SHOTSPRINGS--has Oi horizon; moisture control section is dry 45 to 60 days
SQUATTERFLAT--deeper than 100 cm to restrictive feature
WILTOP--100 to 150 cm to lithic contact
GEOGRAPHIC SETTING:
Elevation--1220 to 2590 m
Climate--cold, moist winters and warm, dry summers
Mean annual precipitation--300 to 460 mm
Mean annual air temperature--4 to 7 degrees C
Frost-free period--40 to 100 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Chen--occur on hillslopes and mountain slopes; 25 to 50 cm to lithic contact
Hackwood--occur on adjacent hillslopes and mountain slopes; contain 18 to 30 percent clay and less than 35 percent fragments in the particle size control section
Tusel-- occur on adjacent hillslopes and mountain slopes; greater than 100 cm to lithic contact; contain 25 to 35 percent clay in the particle size control section
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage--well drained
Flooding--none
Ponding--none
Saturated hydraulic conductivity (Ksat)--high to very high in volcanic ash influenced surface horizons, moderately low in subsurface horizons
USE AND VEGETATION:
Use--livestock grazing and wildlife habitat
Potential native vegetation--bluebunch wheatgrass, Idaho fescue, Sandberg bluegrass, Thurber's needlegrass, mountain big sagebrush, antelope bitterbrush
DISTRIBUTION AND EXTENT:
Distribution--Central and south-central Oregon and northern Nevada
Extent--Moderately Extensive; MLRA's 10, 23, 25, 43C
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Northwest Elko County Area, Nevada, 1986.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
*Mollic epipedon--The zone from the soil surface to 41 cm (A1, A2, and Bt1 horizons).
*Argillic horizon--The zone from 18 to 41 cm (Bt1 and Bt2 horizons).
*Vitrandic intergrade feature--The zone from the soil surface to 41 cm (A1, A2, and Bt1 horizons).
*Lithic contact--The boundary at 64 cm to underlying hard, unweathered bedrock (R layer).
*Particle-size control section--The zone from 18 to 64 cm (Bt1 and Bt2 horizons).
7/2003--updated the taxonomic class from Clayey-skeletal, smectitic, frigid Typic Argixerolls, moved the type location to a more representative area, and clarified the concept of the bedrock contact
1/2019--Conversion to metric
11/2023--This official series description was updated according to SSR01 Technical Note 11--Content and Format of Official Series Descriptions (revised 12/2015). Most of the changes were in formatting; Range in Characteristics was further developed.
ADDITIONAL DATA:
Partial laboratory data are available for this series from the Kellog Soil Survey Laboratory, Lincoln, NE; Pedon ID S2009OR013003 (Crook County, Oregon) and S2014NV007031 (Elko County, Nevada)
National Cooperative Soil Survey
U.S.A.