LOCATION SINTUF OR
Tentative Series
IRD. JRD/DAL/MPR
02/2025
SINTUF SERIES
Landscape--mountains, plateau
Landform--plateaus, scablands, escarpments, ridges
Slope--0 to 70 percent
Parent material--coluvium and residuum derived from pyroclastic tuffs or other hard volcanic rock with an influence of volcanic ash in the upper part
Mean annual precipitation--400 mm
Mean annual air temperature--5 degrees C
Depth class--shallow
Drainage class--well drained
Soil moisture regime--xeric
Soil temperature regime--frigid
Soil moisture subclass--typic
TAXONOMIC CLASS: Loamy-skeletal, isotic, frigid Lithic Ultic Argixerolls
TYPICAL PEDON: Sintuf very channery ashy sandy loam - forested (ponderosa pine, western juniper) on a 2 percent, slightly convex south facing slope; at 1610 meters elevation. (Colors are for air dry soil unless otherwise noted.)
Oi--0 to 3 cm; slightly decomposed needles and twigs
A--3 to 8 cm; brown (10YR 4/3) very channery ashy sandy loam, very dark brown (10YR 2/2) moist; weak thin platy structure; soft, friable, non-sticky and non-plastic; many very fine and fine roots; many very fine and fine interstitial pores; 40 percent channers and 5 percent flagstones; moderately acid (pH 6.0); abrupt smooth boundary. (3 to 8 cm thick)
Bw--8 to 20 cm; brown (10YR 4/3) very channery ashy loam, very dark brown (10YR 2/2) moist; moderate thick platy structure parting to moderate fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine, fine and medium roots; many very fine dendritic tubular pores; 30 percent channers and 10 percent flagstones; moderately acid (pH 5.8); abrupt wavy boundary. (10 to 15 centimeters thick)
2Bt--20 to 43 cm; brown (10YR 4/3) extremely stony silty clay loam, very dark brown (10YR 2/2) moist; strong fine and medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; common fine, medium and coarse roots; many very fine and fine dendritic tubular pores; many thin clay films bridging sand grains and lining pores; 10 percent channers, 25 percent flagstones and 50 percent stones; moderately acid (pH 6.0); clear wavy boundary. (18 to 30 centimeters thick)
2R--43 cm; fractured rhyolitic tuff; indurated
TYPE LOCATION: Harney County, Oregon; Snow Mountain Ranger District, Ochoco National Forest between Bixby and Plumber Springs on the 4335-500 road; SE 1/4 of the SW 1/4 of Section 22, T. 20 S., R. 26 E.; Donnelly Butte USGS 7.5' Quad; latitude 43.8158371, longitude -119.5899833, WGS84 Datum (coordinates determined with a GPS)
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--3 to 7 degrees C
Soil moisture--usually moist, dry for 60 to 90 days in summer and early fall
Mollic epipedon--14 to 50 cm thick
Depth to lithic contact--25 to 50 cm
Properties of layers influenced by volcanic ash
*Ash influenced layer thickness--12 to 22 cm
*Ammonium oxalate extractable Al + Fe--0.4 to 1.0 percent
*Volcanic glass content--15 to 30 percent
Particle-size Control Section
*Clay content (weighted average)--27 to 35 percent
*Total rock fragment content--35 to 85 percent
*Rock fragment type-platy pyroclastic tuff, welded tuff, rhyolite, andesitic tuff
A horizon
*Hue--10YR moist or dry
*Value--2 or 3 moist, 4 or 5 dry
*Chroma--2 or 3 moist, 2 to 4 dry
*Fine earth texture--loamy sand, sandy loam
*Clay content--5 to 15 percent
*Sand content--55 to 85 percent
*Organic matter content--1 to 4 percent
*Total rock fragments content--25 to 60 percent
*Channer content--20 to 40 percent
*Flagstone content--5 to 15 percent
*Stone content--0 to 5 percent
*Reaction--moderately or slightly acid
*Thickness--3 to 7 cm thick
Bw horizon
*Hue--10YR moist or dry
*Value--2 or 3 moist, 4 or 5 dry
*Chroma--2 or 3 moist, 2 to 4 dry
*Fine earth texture--sandy loam, loam
*Clay content--12 to 18 percent
*Sand content--35 to 65 percent
*Organic matter content--1 to 2 percent
*Total rock fragments content--25 to 60 percent
*Channer content--20 to 40 percent
*Flagstone content--5 to 15 percent
*Stone content--0 to 5 percent
*Reaction--moderately or slightly acid
*Thickness--10 to 15 cm
2Bt horizon
*Hue--10YR moist or dry
*Value--2 or 3 moist, 4 to 6 dry
*Chroma--2 or 3 moist, 2 to 4 dry
*Fine earth texture--silty clay loam, sandy clay loam, clay loam
*Clay content--25 to 35 percent
*Sand content--15 to 60 percent
*Organic matter content--0.5 to 1 percent
*Total rock fragments content--35 to 85 percent
*Channer content--10 to 25 percent
*Flagstone content--20 to 25 percent
*Stone content--5 to 50 percent
*Reaction--moderately or slightly acid
*Thickness--18 to 30 cm
COMPETING SERIES:
Hoff- volcanic glass content is 5 to 20 percent; lacks channers or flagstones
GEOGRAPHIC SETTING:
Elevation--1220 to 2050 m
Climate--cold, moist winters and hot, dry summers
Mean annual precipitation--305 to 455 mm
Mean annual air temperature--4 to 8 degrees C
Frost-free period--50 to 100 days
Lithology--pyroclastic welded tuff, generally of the Rattlesnake Formation
GEOGRAPHICALLY ASSOCIATED SOILS:
Ateron--occurs on ridge tops and mountain slopes; 25 to 50 cm to lithic contact; greater than 35 percent clay in control section
Combsflat--occurs on basins, benches, and swales; greater than 150 cm to restrictive feature; thick mantle of volcanic ash
Egyptcreek--occurs on hillslopes, canyon sides, and escarpments; 100 to 150 cm to restrictive feature; lacks argillic horizon
Jushro--occurs on plateaus, edges of scablands and escarpments; minor influence of volcanic ash in surface, lacks Oi horizon
Maule--occurs on plateaus and mountain slopes; 50 to 100 cm to lithic contact; 18 to 36 cm of volcanic ash in surface; greater than 35 percent clay in control section
Wileyflat--occurs on plateaus and rolling hills; 50 to 100 cm to lithic contact
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage--Well drained
Saturation during normal years--none
Flooding--none
Ponding--none
Saturated hydraulic conductivity--moderately high
USE AND VEGETATION:
Use--timber production, wildlife habitat, livestock grazing
Potential native vegetation--Ponderosa pine, western juniper, mountain mahogany, antelope bitterbrush, Wheeler's bluegrass, bluebunch wheat grass, Ross's sedge, bottelbrush squirreltail
Typical plant association--CPS233; Johnson, C.G and Clausnitzer, R.R; 1992; Plant Associations of the Blue and Ochoco Mountains; USDA Forest Service; R6-ERW-TP-036-92 . (Dry Ponderosa Pine Plant Association Group)
DISTRIBUTION AND EXTENT: Central Oregon, Southwestern Blue Mountains, MLRA 10. The soil is of moderate extent.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: Crook County Area (Ochoco National Forest), Oregon, 2009.
REMARKS:
Diagnostic horizons and other features recognized in this pedon are
*Mollic epipedon--3 to 20 cm (A, Bw )
*Argillic horizon--20 to 43 cm (2Bt horizon)
*Particle size control section--20 to 43 cm(2Bt horizon)
*Vitandic subgrooup properties--3 to 20 cm (A, Bw horizons)
*Lithic contact--43 cm (top of R layer)
National Cooperative Soil Survey
U.S.A.