LOCATION POWELLBUTTE OR
Tentative Series
IRD. GDM/TDT
02/2025
POWELLBUTTE SERIES
Landscape--foothills of the Blue and Ochoco Mountains
Landform--hillslopes, lava plains, plateaus, benches
Slope--0 to 65 percent
Parent Material--colluvium and residuum derived from basalt or tuff with an influence of volcanic ash in the surface
Mean annual precipitation--about 330 mm
Mean annual air temperature--about 6 degrees C
Depth class--moderately deep
Drainage class--well drained
Soil moisture regime--xeric
Soil temperature regime--frigid
Soil moisture subclass--typic
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Vitrandic Argixerolls
TYPICAL PEDON: Powellbutte gravelly ashy loam--rangeland; on a 15 percent north facing slope at an elevation of 1178 m.
A--0 to 13 cm; gravelly ashy loam, dark grayish brown (10YR 4/2) dry, very dark brown (10YR 2/2) moist; weak fine granular structure; soft, very friable, nonsticky, nonplastic; many very fine and fine roots throughout; many fine vesicular pores; 10 percent subangular cobbles by volume, 15 percent subangular gravel by volume; noneffervescent; neutral (pH 6.7); clear smooth boundary
AB--13 to 28 cm; gravelly ashy loam, dark grayish brown (10YR 4/2) dry, very dark brown (10YR 2/2) moist; weak fine and medium subangular blocky structure; soft, very friable, slightly sticky, slightly plastic; many very fine and fine roots throughout and few medium roots throughout; many very fine and fine dendritic tubular pores; 15 percent subangular gravel by volume; noneffervescent; neutral (pH 6.8); clear smooth boundary
2Bt1--28 to 48 cm; gravelly clay loam, grayish brown (10YR 5/2) dry, very dark grayish brown (10YR 3/2) moist; moderate fine and medium subangular blocky structure; hard, firm, slightly sticky, slightly plastic; few medium roots throughout and common fine roots throughout; common fine dendritic tubular pores; 4 percent faint clay films on faces of peds and in pores; 15 percent subangular gravel by volume; noneffervescent; neutral (pH 7.0); clear smooth boundary
2Bt2--48 to 64 cm; gravelly clay, grayish brown (10YR 5/2) dry, very dark grayish brown (10YR 3/2) moist; strong fine and medium subangular blocky structure; very hard, very firm, moderately sticky, moderately plastic; few fine to coarse roots throughout; few fine dendritic tubular pores; 4 percent distinct clay films on faces of peds and in pores; 25 percent subangular gravel by volume; noneffervescent; neutral (pH 7.2); abrupt smooth boundary
2Crt--64 to 71 cm; weathered basalt bedrock; moderately coherent; 5 percent distinct clay films in cracks
2R--71 to 81 cm; basalt bedrock
TYPE LOCATION: Crook County, Oregon, 100 feet south and 1500 feet west of the NE corner section 23, T. 16S, R. 16E: latitude 44.1742998, longitude -120.7750028, datum WGS84 (coordinates estimated from PLSS details)
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--6 to 8 degrees C
Soil Moisture--usually moist, but are dry in all parts of the moisture control section for 70 to 90 consecutive days within the four months that follow the summer solstice
Thickness of mollic epipedon--50 to 75 cm
Depth to argillic horizon--18 to 36 cm
Depth to lithic contact--50 to 100 cm
Estimated properties of layers influenced by volcanic ash
*Ammonium oxalate extractable Al + Fe--0.4 to 1.0 percent
*0.02 to 2.0 mm fraction--greater than 30 percent
*Volcanic glass in the 0.02 to 2.0 mm fraction--15 to 30 percent
Particle Size Control Section:
Clay--27 to 35 percent
Total rock fragments--5 to 35 percent
Gravel--5 to 35 percent
Cobble--0 to 10 percent
A horizon
*Hue--10YR
*Value--2 or 3 moist, 3 or 4 dry
*Chroma--1 or 2 moist and dry
*Fine earth texture--loam, sandy loam
*Clay--10 to 18 percent
*Sand--35 to 60 percent
*Total fragments--5 to 40 percent
*Gravel--5 to 20 percent
*Cobble--0 to 10 percent
*Stones--0 to 10 percent
*Organic matter--2 to 6 percent
*Reaction--pH 6.6 to 7.3 (neutral)
AB horizon
*Hue--10YR
*Value--2 or 3 moist, 3 to 5 dry
*Chroma--1 or 2 moist and dry
*Fine earth texture--sandy loam, loam, clay loam
*Clay--15 to 27 percent
*Sand--35 to 60 percent
*Total fragments--5 to 30 percent
*Gravel--5 to 20 percent
*Cobble--0 to 10 percent
*Organic matter--2 to 5 percent
*Reaction--pH 6.6 to 7.3 (neutral)
2Bt horizons
*Hue--10YR
*Value--2 or 3 moist, 4 or 5 dry
*Chroma--2 to 4 moist and dry
*Fine earth texture--sandy clay loam, clay loam, clay
*Clay--27 to 45 percent
*Sand--20 to 45 percent
*Total fragments--5 to 35 percent
*Gravel--5 to 35 percent
*Organic matter--1.0 to 3 percent
*Reaction--pH 6.6 to 7.8 (neutral to slightly alkaline)
COMPETING SERIES:
Fastjet--50 to 100cm to paralithic contact
Luckycreek--greater than 200 cm to root restriction
Pagecreek--moist intermittently for 10 to 20 days in the upper part due to summer convection storms
Pinney--greater than 200 cm to root restriction
Runyon--5 to 20 percent volcanic glass in the upper part
Tensed--greater than 200 cm to root restriction
Tommycork--5 to 15 percent glass and 15 to 45 percent sand in the surface horizon, control section averages 20 to 35 percent clay and 0 to 10 percent coarse fragments
GEOGRAPHIC SETTING:
Elevation--910 to 1830 m
Slope--0 to 65 percent
Climate--cold wet winters, hot dry summers
Mean annual precipitation--305 to 360 mm
Mean annual air temperature--5 to 7 degrees C
Frost-free period--50 to 90 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Anatone--occur on adjacent ridges; loamy-skeletal, shallow to lithic contact
Booth--occur on plateaus; averages greater than 35 percent clay in the control section, minor influence of ash in the surface
Lickskillet--occur on adjacent south facing sideslopes; loamy-skeletal, shallow to lithic contact
Skullhollow--occur on hillslopes and canyonslopes; loamy-skeletal, moderately deep to lithic contact
Luckycreek--occur on swales and drainageways; very deep to root restriction
DRAINAGE AND PERMEABILITY:
Drainage--well drained
Flooding--none
Ponding--none
Saturated hydraulic conductivity (Ksat)--moderately high to high in upper horizons, moderately low to moderately high in lower horizons
USE AND VEGETATION:
Use--livestock grazing, wildlife habitat
Vegetation--Idaho fescue, bluebunch wheatgrass, mountain big sagebrush, western juniper
Typical Ecological Site--SR Mountain 12-16 PZ (R010XC032OR)
DISTRIBUTION AND EXTENT:
Central Oregon; MLRA 10; moderate extent
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED:
Crook County Area, Oregon; 1999
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
*Mollic epipedon (Pachic)--surface to depth of 64 cm
*Argillic horizon--11 to 64 cm
*Paralithic horizon--not present in some pedons
*Particle-size control section - from 13 to 63 cm (AB, 2Bt1 and 2Bt2 horizons)
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; no major technical changes were made.
National Cooperative Soil Survey
U.S.A.