LOCATION THAYVILLE               OR

Tentative Series
IRD. AGG/DEW
08/2025

THAYVILLE SERIES

Landscape--Eastern Cascade mountains
Landform--moraines
Slope--5 to 50 percent slopes
Parent Material--volcanic ash mixed with till and/or colluvium derived from till
Mean annual precipitation--810 mm
Mean annual air temperature--5 degrees C
Depth class--very deep
Drainage class--somewhat excessively drained
Soil moisture regime--xeric
Soil temperature regime--cryic
Soil moisture subclass--typic

TAXONOMIC CLASS: Ashy-skeletal, glassy Humic Xeric Vitricryands

TYPICAL PEDON: Thayville ashy sandy loam, forested, on a 14 percent slope at an elevation of 1602 meters. (Colors are for dry soil unless otherwise noted.)

Oi--0 to 6 centimeters; slightly decomposed plant material; strongly acid (pH 5.5); abrupt wavy boundary.

A1--6 to 11 centimeters; dark gray (10YR 4/1) ashy sandy loam, black (10YR 2/1) moist; weak medium subangular blocky structure; soft, friable, nonsticky, nonplastic; common very fine and fine roots throughout; many very fine tubular and common fine irregular pores; 2 percent subrounded gravel; slightly acid (pH 6.2); abrupt smooth boundary.

A2--11 to 25 centimeters; brown (10YR 5/3) ashy sandy loam, very dark grayish brown (10YR 3/2) moist; moderate medium subangular blocky structure; soft, friable, nonsticky, nonplastic; common very fine and fine roots throughout; common fine irregular and fine tubular pores; 12 percent subrounded gravel; slightly acid (pH 6.4); clear smooth boundary.

Bw1--25 to 56 centimeters; brown (10YR 5/3) gravelly ashy sandy loam, dark brown (10YR 3/3) moist; moderate medium and coarse subangular blocky structure; soft, friable, nonsticky, nonplastic; common very fine and fine, and few medium and coarse roots throughout; few fine irregular and common fine tubular pores; 20 percent subrounded gravel; slightly acid (pH 6.5); gradual smooth boundary.

Bw2--56 to 81 centimeters; yellowish brown (10YR 5/4) very gravelly ashy loamy sand, dark yellowish brown (10YR 4/4) moist; weak medium subangular blocky structure; soft, very friable, nonsticky, nonplastic; common fine and medium, and few coarse roots throughout; few fine irregular pores; 38 percent subrounded gravel and 5 percent subrounded cobbles; neutral (pH 6.8); clear irregular boundary.

BC--81 to 128 centimeters; yellowish brown (10YR 5/4) extremely stony ashy sandy loam, dark yellowish brown (10YR 3/4) moist; weak medium subangular blocky structure parts to single grain; soft, very friable, nonsticky, nonplastic; common fine and medium, and few coarse roots around fragments; few fine irregular pores; 25 percent subrounded gravel, 10 percent subrounded cobbles, and 40 percent subrounded stones; neutral (pH 7.0); gradual smooth boundary.

C--128 to 152 centimeters; light yellowish brown (10YR 6/4) extremely stony ashy sandy loam, dark yellowish brown (10YR 3/4) moist; single grain; loose, nonsticky, nonplastic; 10 percent subrounded gravel, 15 percent subrounded cobbles, and 55 percent subrounded stones; neutral (pH 7.1)

TYPE LOCATION: Deschutes County, Oregon; SW 1/4, NE 1/4 of section 19, T. 16 S, R. 9 E; Latitude 44.1765920, Longitude -121.6915080 datum WGS84 (coordinates determine with a GPS).

RANGE IN CHARACTERISTICS:
Mean annual soil temperature--5.2 to 7.2 degrees C
Soil moisture--usually moist in winter and spring, dry in the moisture control section for 45 to 60 days in the 4 months following the summer solstice
Thickness of ash influenced layers--over 100 cm

Estimated properties of layers influenced by volcanic ash
Ammonium oxalate extractable Al + Fe--0.4 to 1.0 percent
1500 kPa water content (air dry)--3 to 12 percent
0.02 to 2.0 mm fraction--55 to 90 percent
Medium to very coarse sand in the .02 to 2.0 mm fraction--greater/less (?) than 50 percent
Volcanic glass in the 0.02 to 2.0 mm fraction--40 to 80 percent
P retention--25 to 50 percent

Particle-size control section: mineral soil surface to 100 cm below the soil surface
Clay content, weighted average--1 to 10 percent
Rock fragment content, weighted average--35 to 85 percent

A horizons
Hue--10YR
Value--2 or 3 moist, 3 to 5 dry
Chroma--1 to 3
Fine earth texture--ashy sandy loam or ashy loamy sand
Clay content--2 to 10 percent
Sand content--55 to 90 percent
Organic matter--1 to 4 percent
Total rock fragment content--0 to 45 percent
Gravel (subrounded)--0 to 35 percent
Cobble (subrounded)--0 to 10 percent
Reaction--pH 5.6 to 6.5 (moderately to slightly acid)
Thickness--combined thickness of A horizons is 18 to 40 cm

Bw horizons
Hue--10YR
Value--3 to 5
Chroma--3 to 6
Fine earth texture--ashy sandy loam or ashy loamy sand
Clay content--1 to 10 percent
Sand content--55 to 90 percent
Organic matter--0.25 to 1.25 percent
Total rock fragment content--20 to 65 percent
Gravel (subrounded)--20 to 45 percent
Cobble (subrounded)--0 to 15 percent
Stone (subrounded)--0 to 5 percent
Reaction--6.1 to 7.3 (slightly acid to neutral)
Thickness--30 to 70 cm

BC horizon (when present)
Hue--10YR
Value--3 to 5 moist, 5 to 7 dry
Chroma--4 or 6
Fine earth texture--ashy sandy loam or ashy loamy sand
Clay content--1 to 8 percent
Sand content--55 to 90 percent
Organic matter--0.10 to 0.25 percent
Total rock fragment content--40 to 85 percent
Gravel (subrounded)--20 to 45 percent
Cobble (subrounded)--10 to 30 percent
Stone (subrounded)--10 to 40 percent
Reaction--pH 6.6 to 7.3 (neutral)
Thickness--0 to 50 cm

C horizon
Hue--10YR
Value--3 to 5 moist, 5 to 7 dry
Chroma--4 or 6
Fine earth texture--ashy sandy loam, ashy loamy sand or ashy loamy coarse sand
Clay content--1 to 8 percent
Sand content--55 to 90 percent
Organic matter--0 to 0.20 percent
Total rock fragment content--40 to 85 percent
Gravel (subrounded)--10 to 45 percent
Cobble (subrounded)--10 to 30 percent
Stone (subrounded)--20 to 55 percent
Reaction--pH 6.6 to 7.3 (neutral)
Thickness--20 to 80 cm

COMPETING SERIES:
Bagmont--50 to 100 cm to paralithic contact, has a cambic horizon
Longval--fine sand fraction greater than 25 percent and very fine sand fraction greater than 15 percent throughout the particle-size control section, has a mollic epipedon
Lotawaca--100 to 150 cm to paralithic contact, has an argillic horizon

GEOGRAPHIC SETTING:
Elevation--1300 to 1850 m
Climate--cold, wet winters and cool, dry summers
Mean annual precipitation--640 to 1100 mm
Mean annual air temperature--4.2 to 6.2 degrees C
Frost-free period--20 to 50 days

GEOGRAPHICALLY ASSOCIATED SOILS:
Cultus--occurs on moraines; averages less than 35 percent fragments within the particle-size control section
Romtom--occurs in swales on glacial valley floors; averages less than 35 percent fragments within the particle-size control section
Wuksi--occurs on lava plains and mountain slopes; ochric epipedon

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage--somewhat excessively drained
Saturated hydraulic conductivity (Ksat)--high to very high throughout

USE AND VEGETATION:
Use--timber production, wildlife habitat
Vegetation--ponderosa pine, lodgepole pine, Douglas fir, white fir, greenleaf manzanita, wax currant, snowbrush ceanothus, Ross' sedge

DISTRIBUTION AND EXTENT:
East slopes of the Cascade Mountains in central Oregon; MLRA 06; small extent

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana

SERIES PROPOSED:
Deschutes County, Deschutes National Forest, Oregon 2025; name is coined

REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Particle-size control section--6 to 106 cm (A1, A2, Bw1, Bw2, and part of the BC horizon)
Umbric epipedon--6 to 56 cm (A1, A2, and Bw1 horizons)
Andic soil properties--6 to 152 cm (A1, A2, Bw1, Bw2, BC, and C horizons)

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National Cooperative Soil Survey
U.S.A.