LOCATION BROWLO                  OR

Tentative Series
IRD. AGG/DEW
08/2025

BROWLO SERIES

Landscape--Eastern Cascade mountains
Landform--buttes, mountain slopes
Slope--5 to 75 percent slopes
Parent Material--volcanic ash and pumice over colluvium and/or residuum derived from igneous rock
Mean annual precipitation--710 mm
Mean annual air temperature--6.0 degrees C
Depth class--very deep
Drainage class--well drained
Soil moisture regime--xeric
Soil temperature regime--frigid
Soil moisture subclass--typic

TAXONOMIC CLASS: Ashy over loamy-skeletal, glassy over isotic, frigid Typic Vitrixerands

TYPICAL PEDON: Browlo ashy loamy sand, forested, on a 11 percent slope at an elevation of 1430 meters. (Colors are for dry soil unless otherwise noted.)

Oi--0 to 4 centimeters; slightly decomposed plant material; strongly acid (pH 5.5); clear wavy boundary.

A--4 to 16 centimeters; gray (10YR 5/1) ashy loamy sand, very dark grayish brown (10YR 3/2) moist; weak very coarse granular structure; soft, very friable, nonsticky, nonplastic; common very fine and few fine roots throughout; few fine irregular pores; 2 percent fine pumice paragravel and 3 percent gravel; slightly acid (pH 6.3); clear smooth boundary.

Bw--16 to 35 centimeters; yellowish brown (10YR 5/4) ashy loamy coarse sand, dark yellowish brown (10YR 4/4) moist; weak medium subangular blocky structure; soft, very friable, nonsticky, nonplastic; few fine, common medium and coarse roots throughout; common fine irregular pores; 2 percent fine pumice paragravel and 10 percent gravel; slightly acid (pH 6.5); gradual smooth boundary.

C--35 to 72 centimeters; yellow (10YR 7/8) paragravelly ashy loamy coarse sand, yellowish brown (10YR 5/8) moist; single grain; loose, nonsticky, nonplastic; few fine and coarse, common medium roots throughout; common medium irregular pores; 18 percent fine pumice paragravel, 2 percent cobbles, and 5 percent stones; neutral (pH 6.8); gradual wavy boundary.

2Ab--72 to 105 centimeters; brown (10YR 4/3) very gravelly sandy loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky parts to moderate fine granular structure; soft, friable, slightly sticky, nonplastic; few fine and coarse roots throughout; few fine irregular pores; 25 percent gravel and 10 percent cobbles; neutral (pH 7.0); clear smooth boundary.

2Bwb--105 to 152 centimeters; yellowish brown (10YR 5/4) very cobbly sandy loam, dark yellowish brown (10YR 3/4) moist; moderate medium subangular blocky; soft, friable, slightly sticky, nonplastic; very few fine roots throughout; few very fine tubular pores; 20 percent gravel and 20 percent cobbles; neutral (pH 7.0).

TYPE LOCATION: Deschutes County, Oregon; SE 1/4, SE 1/4 section 26, T. 21 S, R. 9 E, Willamette Meridian; Latitude 43.7205960, Longitude -121.6038640, datum WGS84 (coordinates determined with a GPS).

RANGE IN CHARACTERISTICS:
Mean annual soil temperature--6.5 to 8.0 degrees C
Soil moisture--usually moist in winter and spring, dry in the moisture control section for 60 to 90 days in the 4 months following the summer solstice
Thickness of ash influenced layers--50 to 80 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 than 50 percent
Volcanic glass in the 0.02 to 2.0 mm fraction--50 to 90 percent
P retention--25 to 50 percent

Particle-size control section: mineral soil surface to 100 cm below the mineral soil surface
(Upper part of the particle-size control section)
Clay content, weighted average--1 to 5 percent
Rock fragment content, weighted average--0 to 35 percent
(Lower part of the particle-size control section)
Clay content, weighted average--5 to 18 percent
Rock fragment content, weighted average--35 to 85 percent

A horizon
Hue--10YR
Value--3 to 5
Chroma--1 to 3
Fine earth texture--ashy loamy sand or ashy loamy coarse sand
Clay content--1 to 5 percent
Sand content--70 to 90 percent
Organic matter--2.0 to 4.0 percent
Total rock fragment content--0 to 35 percent
Pumice paragravel--0 to 15 percent
Gravel--0 to 35 percent
Reaction--5.6 to 6.5 (moderately to slightly acid)
Thickness--5 to 15 cm

Bw horizon
Hue--10YR
Value--5 or 6 dry, 4 or 5 moist
Chroma--3 to 6
Fine earth texture--ashy loamy sand or ashy loamy coarse sand
Clay content--1 to 5 percent
Sand content--70 to 90 percent
Organic matter--0.5 to 2.0 percent
Total rock fragment content--0 to 35 percent
Pumice paragravel--0 to 20 percent
Gravel--0 to 35 percent
Reaction--6.1 to 7.3 (slightly acid to neutral)
Thickness--15 to 40 cm

C horizon
Hue--10YR
Value--5 to 8
Chroma--4 to 8
Fine earth texture--ashy loamy sand, ashy loamy coarse sand, or ashy coarse sand
Clay content--1 to 5 percent
Sand content--70 to 95 percent
Organic matter--0.1 to 0.5 percent
Total rock fragment content--0 to 60 percent
Pumice paragravel--0 to 30 percent
Gravel--0 to 35 percent
Cobble--0 to 5 percent
Stone--0 to 5 percent
Reaction--6.1 to 7.3 (slightly acid to neutral)
Thickness--30 to 50 cm

2Ab horizon
Hue--7.5YR or 10YR
Value--3 to 5
Chroma--2 to 4
Fine earth texture--sandy loam or coarse sandy loam
Clay content--5 to 18 percent
Sand content--55 to 70 percent
Organic matter--0.2 to 0.5 percent
Total rock fragment content--35 to 85 percent
Gravel--25 to 40 percent
Cobble--10 to 35 percent
Stone--0 to 10 percent
Reaction--6.6 to 7.3 (neutral)
Thickness--10 to 35 cm

2Bwb horizon
Hue--7.5YR or 10YR
Value--3 to 6
Chroma--3 to 6
Fine earth texture--sandy loam or coarse sandy loam
Clay content--5 to 18 percent
Sand content--55 to 70 percent
Organic matter--0.1 to 0.4 percent
Total rock fragment content--35 to 85 percent
Gravel--20 to 40 percent
Cobble--15 to 35 percent
Stone--0 to 10 percent
Reaction--6.6 to 7.3 (neutral)
Thickness--15 to 50 cm

COMPETING SERIES:
Bonner--35 to 66 cm of volcanic ash surface; dry for 45 to 60 days in the soil moisture control section after the summer solstice
Brannan--100 to 150 cm to lithic contact; dry in the moisture control section for 45 to 60 consecutive days following the summer solstice
Capoose--50 to 100 cm to lithic contact; upper portion of the particle-size control section averages less than 55 percent sand
Crackler--100 to 150 cm to lithic contact; dry for 45 to 60 days in the soil moisture control section after the summer solstice; averages 18 to 35 percent clay in the particle-size control section
Elbowlake--50 to 100 cm to densic contact; has a cambic horizon within 100cm of the mineral soil surface
Farway--depth to buried loamy-skeletal material less than 50 cm; has a cambic horizon within 100cm of the mineral soil surface
Kellerbutte--upper portion of the particle-size control section averages less than 50 percent sand; dry in the moisture control section for 45 to 75 days following the summer solstice
Kootenai--dry in the moisture control section for 45 to 60 consecutive days following the summer solstice; allows textures finer than sandy loam in the particle-size control section
Natapoc--depth to buried loamy-skeletal material less than 50 cm; volcanic glass content of 30 to 60 percent; recognizes an albic and cambic horizon(s); compact till at 48 to 150 cm
Nevine--50 to 100 cm to densic contact; upper portion of the particle-size control section typically averages less than 70 percent sand
Olot--50 to 100 cm to lithic contact; averages less than 55 percent sand in the particle-size control section
Rouen--50 to 100 cm to lithic contact; 35 to 76 cm of volcanic ash surface
Saska--recognizes an albic and spodic horizon(s)
Twocolor--dry in the moisture control section for 45 to 60 consecutive days following the summer solstice; depth to buried loamy-skeletal material less than 50 cm
Vingulch--50 to 100 cm to lithic contact; depth to buried loamy-skeletal material less than 50 cm

GEOGRAPHIC SETTING:
Elevation--1300 to 1575 m
Climate--cool, wet winters and warm, dry summers
Mean annual precipitation--480 to 890 mm
Mean annual air temperature--5.5 to 7.0 degrees C
Frost-free period--50 to 80 days
Lithology--volcanic ash derived from Mazama over older colluvium and/or residuum derived from volcanic rock

GEOGRAPHICALLY ASSOCIATED SOILS:
Wanoga--occurs on volcanic uplands; 50 to 100 cm to lithic contact; has a mollic epipedon
Shroyton--occurs on higher elevation mountain slopes; has a mollic epipedon; cryic soil temperature regime
Shanahan, Shukash--occur within cold air drainages on pumice mantled terraces, ridges, cinder cones, benches, lava plains, and lava plateaus; cryic soil temperature regime
Klawhop--occurs on lava flows and plains; 25 to 50 cm to lithic contact; cryic soil temperature regime
Ipsoot--occurs on higher elevation cinder cones; is 50 to 100 cm to cinders; cryic soil temperature regime

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage--well drained
Saturated hydraulic conductivity (Ksat)--high to very high (in the upper portion of the profile), high (in the lower portion of the profile)

USE AND VEGETATION:
Use--timber production, wildlife habitat
Vegetation--ponderosa pine, white fir, grand fir, sugar pine, Douglas-fir, greenleaf manzanita, golden chinquapin, antelope bitterbrush, snowbrush ceanothus, Ross' sedge, Idaho fescue, western needlegrass, and bottlebrush squirreltail

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; the name is coined

REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Particle-size control section--4 to 104 cm (A, Bw, C, and part of the 2Ab horizon)
Ochric epipedon--4 to 16 cm (A horizon)
Andic soil properties--4 to 72 cm (A, Bw, and C horizons)
Lithological discontinuity--72 to 152 cm (2Ab horizon)
Cambic horizon (buried)--105 to 152 cm (2Bwb horizon)

ADDITIONAL DATA:
Laboratory data inferred from geographically associated and similar Shanahan (Pedon #:
87P0518) and Shukash series (Pedon #: 02N0456). This data is available from the NRCS-NSSC-Kellogg Soil Survey Laboratory, Lincoln, Nebraska.

---

National Cooperative Soil Survey
U.S.A.