LOCATION OTWIN                   OR

Established Series
Rev. RHB/CEG/TDT
02/2025

OTWIN SERIES

Landscape--Cascade Mountains
Landform--ground moraines, glaciated hillslopes, mountain slopes, cirque headwalls, ridges, plateaus, structural benches
Slope--0 to 90
Parent material--colluvium, till and residuum derived from basalt and andesite mixed with volcanic ashthroughout
Mean annual precipitation--about 1020 mm
Mean annual air temperature--about 5.5 degrees C
Depth class--moderately deep to bedrock
Drainage class--well drained
Soil moisture regime--udic
Soil temperature regime--cryic
Soil moisture subclass--typic

TAXONOMIC CLASS: Medial-skeletal, amorphic Typic Haplocryands

TYPICAL PEDON: Otwin gravelly medial loam, in conifer forest, with a slope of 4 percent, with 2 percent surface stones and 0.5 percent surface boulders, at an elevation of 1740 m. When described on October 27, 2011, the soil was moist from 15 to 30 cm and dry in all other parts.

Oi--0 to 2 cm; slightly decomposed twigs and needles; slightly acid (pH 6.2); clear smooth boundary.

Oe--2 to 6 cm; moderately decomposed twigs and needles; moderately acid (pH 6.0); clear smooth boundary

A/E--6 to 21 cm; 70 percent gravelly medial loam, reddish brown (5YR 4/4) dry, dark reddish brown (5YR 3/3) moist, (A part); 30 percent very gravelly medial loam, light reddish brown (5YR 6/3) dry, reddish brown (5YR 4/4), moist (E part); moderate fine granular structure; very friable, soft, slightly sticky and nonplastic; few coarse and very coarse roots and common medium, fine and very fine roots (A part); few very coarse roots, common medium roots and many fine roots (E part); common fine dendritic tubular pores; 33 percent gravel and 2 percent cobbles; neutral (pH 7.0) (A part), and slightly acid (pH 6.4) (E part); clear wavy boundary

Bw1--21 to 45 cm; very gravelly medial loam, reddish brown (5YR 5/4) dry, dark reddish brown (5YR 3/4) moist; weak medium subangular blocky structure; very friable, soft, slightly sticky and nonplastic; few very coarse, coarse, medium, fine and very fine roots; common fine irregular and few fine dendritic tubular pores; 40 percent gravel, 10 percent cobbles, and 5 percent stones; slightly acid (pH 6.2); gradual wavy boundary.

Bw2--45 to 70 cm; extremely stony medial loam, brown (7.5YR 5/4) dry, dark brown (7.5YR 3/4) moist; weak medium subangular blocky structure; very friable, slightly hard, slightly sticky and nonplastic; common very coarse and coarse roots and few medium and fine roots; common fine irregular and few fine dendritic tubular pores; 2 percent boulders, 20 percent stones, 25 percent cobbles, and 20 percent gravel; moderately acid (pH 5.6); gradual irregular boundary

R--70 cm; very strongly cemented andesite.

TYPE LOCATION: Klamath County, Oregon, about 11.4 miles north and 10.5 miles west of the community of Keno; approximately 713 m north and 698 m west of the southeast corner of sec. 5, T. 38 S., R. 6 E., Willamette Meridian; Lake Of The Woods South, Oregon, U.S. Geological Survey quadrangle; Latitude 42.2925750 degrees, Longitude -122.1382389, datum WGS 84 (coordinates determined with a GPS device)

RANGE IN CHARACTERISTICS:

Mean annual soil temperature--5.0 to 7.8 degrees C
Mean summer soil temperature with an O horizon--6.7 to 8.3 degrees C
Mean summer soil temperature without an O horizon--10 to 14.4 degrees C
Moisture control section--dry for 30 to 45 consecutive days
Rock fragments--subrounded
Depth to restriction--50 to 100 cm to bedrock (lithic contact)
*Thickness of volcanic ash influenced layers--50 to 100 cm (all horizons)

Estimated properties of layers influenced by volcanic ash
*1/3-bar bulk density--0.85 to 1.0 g/cm3 in A horizons; 1.1 to 1.4 g/cm3 in B horizons
*Volcanic glass in 0.02 to 2.0 mm fraction--15 to 30 percent
*0.02 to 2.0 mm fraction--greater than 30 percent
*Ammonium oxalate extractable Al + 1/2Fe--3 to 5 percent
*Phosphate retention--75 to 100 percent
*15-bar water dry--15 to 30 percent (dried samples), 30 to 100 percent (undried samples)
*Acid oxalate extractable silica--2 to 3 percent

Surface Rock Fragments
*Stones--1 to 3 percent surface cover
*Boulders--0.1 to 1 percent surface cover

Particle size control section
*Clay--10 to 18 percent clay
*Sand--40 to 75 percent sand; less than 50 percent of the 0.02 to 0.20 mm fraction is medium to very coarse sand
*Total rock fragment--30 to 60 percent

O horizons:
*Thickness--3 to 8 cm

A/E horizon, A portion:
*Hue--10YR or 7.5YR
*Value--3 moist and 3 or 4 dry
*Chroma--2 through 4 moist and 3 or 4 dry
*Clay--10 to 18 percent
*Sand--30 to 75 percent
*Organic matter--0.5 to 4.0 percent
*Total fragments--10 to 45 percent
*Gravel--10 to 45 percent
*Cobbles--0 to 15 percent
*Stones--0 to 15 percent
*Reaction--5.6 to 7.3 (moderately acid to neutral)
*Thickness--5 to 30 cm

A/E horizon, E portion (when present):
*Hue--10YR or 7.5YR
*Value--4 or 5 moist and 5 or 6 dry
*Chroma--2 through 4 moist and 3 or 4 dry
*Fine earth texture--medial loam or medial fine sandy loam
*Clay--10 to 18 percent
*Sand--30 to 75 percent
*Organic matter--0.5 to 1.0 percent
*Total fragments--10 to 45 percent
*Gravel--10 to 45 percent
*Cobbles--0 to 15 percent
*Stones--0 to 15 percent
*Reaction--5.6 to 6.5 (moderately acid or slightly acid)
*Thickness--0 to 15 cm

Bw horizons:
*Hue--10YR or 7.5YR
*Value--3 or 4 moist and 4 or 5 dry
*Chroma--3 or 4 moist and dry
*Fine earth texture--medial loam or medial sandy loam
*Clay--10 to 18 percent
*Sand--30 to 75 percent
*Organic matter--0.1 to 2.0 percent
*Total fragments--25 to 70 percent
*Gravel--10 to 60 percent
*Cobbles--2 to 40 percent
*Stones--0 to 40 percent
*Boulders--0 to 25 percent
*Reaction--5.6 to 6.5 (moderately acid or slightly acid)
*Thickness--20 to 90 cm

COMPETING SERIES:
Battleax--over 100 cm to a restrictive feature; umbric epipedon
Divers--over 100 cm to a restrictive feature
Highcamp--over 100 cm to a restrictive feature; less than 40 percent sand
Holderman--1/3-bar bulk density 0.65 to 0.9 g/cm3; less than 50 percent sand; 18 to 24 percent clay
Hummington--1/3-bar bulk density 0.65 to 0.90 g/cm3; umbric epipedon
Icecap--1/3-bar bulk density 0.60 to 0.90 g/cm3; 18 to 27 percent clay; umbric epipedon
Idanha--1/3-bar bulk density 0.60 to 0.90 g/cm3; umbric epipedon
Ohana--50 to 100 cm (moderately deep) to a densic contact; 35 to 50 percent pumice pararock fragments in the surface horizons; lithologic discontinuity, with glacial till in the subsurface
Oatman--over 100 cm to a restrictive feature

GEOGRAPHIC SETTING:
Elevation--1500 to 2400 m
Slope--0 to 90 percent
Climate--humid, with precipitation occurring mainly in winter and spring
Mean annual precipitation--900 to 1780 mm
Mean annual air temperature--3.9 to 7.0 degrees C
Mean January air temperature--0 to 1.7 degrees C
Frost-free period--10 to 50 days

GEOGRAPHICALLY ASSOCIATED SOILS:
Kyotesue--over 100 cm (deep or very deep) to a restrictive feature; frigid temperature regime
Oatman--over 100 cm (deep or very deep) to a restrictive feature
Molawa--over 100 cm (deep or very deep) to a restrictive feature; medial (less than 35 percent rock fragments)
Woodcock--over 100 cm (deep or very deep) to a restrictive feature; have an argillic horizon, a mollic epipedon, a xeric soil moisture regime and a frigid temperature regime
Pokegema--over 100 cm (deep or very deep) to a restrictive feature; medial (less than 35 percent rock fragments), have a mollic epipedon, a xeric soil moisture regime and a frigid temperature regime

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--Well drained
Saturated hydraulic conductivity (Ksat)--very high in O horizons; high in mineral horizons

USE AND VEGETATION:
Use--timber production, wildlife habitat, recreation, and livestock grazing
Overstory vegetation--white fir, Shasta red fir, western white pine, ponderosa pine
Understory vegetation--mountain brome, western princes pine

DISTRIBUTION AND EXTENT: Cascade Mountains in southern Oregon; MLRA 3; limited extent.

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

SERIES ESTABLISHED: Jackson County Area, Oregon (Klamath County part); 1988.

REMARKS:
Diagnostic horizons and other features in this pedon
*Particle-size control section--6 to 70 cm
*Ochric epipedon
*Andic soil properties--6 to 70 cm
*Volcanic glass--6 to 70 cm
*Cambic horizon--21 to 70 cm
*Lithic contact--the boundary at 70 cm
*Udic moisture regime--based on correlation with Shasta red fir and white fir plant associations and ecological sites.
*Haplocryand--15 bar water dry is less than 15 percent throughout the profile.
*Medial--Andic soil properties are present throughout the control section. The 15 bar water dry is more than 15 percent throughout.
*Amorphic--The particle-size control section has over 2 percent acid oxalate extractable silica

ADDITIONAL DATA:
*NASIS Site ID--11OR035014
*NASIS Pedon ID--11OR035014
*Andic soil properties based on laboratory data from the similar Kyotesue series, NSSL S01OR-035-002, -003, -004, and -005.

05/2011--Classification changed from Loamy-skeletal, mixed Andic Cryochrepts to Medial-skeletal, amorphic Typic Haplocryands

02/2012--Type location moved and re-described in 2012 to better reflect correlation of udic moisture regime to Shasta red fir plant association; NASIS user pedon id: 11OR035014

06/2017--Updated this official series description according to SSRO1 Technical Note 11, OSD-- Format of Official Series Descriptions (revised 12/2015). Most of the changes were in formatting.

---

National Cooperative Soil Survey
U.S.A.