LOCATION MOFFITT OR
Tentative Series
IRD. AGG/KLM/DEW
08/2025
MOFFITT SERIES
Landscape--Eastern Cascade mountains
Landform--mountain slopes, lava flows, or lava plains
Slope--0 to 50 percent slopes
Parent Material--pumice over volcanic ash
Mean annual precipitation--400 mm
Mean annual air temperature--5 degrees C
Depth class--very deep
Drainage class--excessively drained
Soil moisture regime--xeric
Soil temperature regime--cryic
Soil moisture subclass--typic
TAXONOMIC CLASS: Pumiceous, glassy Xeric Vitricryands
TYPICAL PEDON: Moffitt very paragravelly ashy loamy coarse sand, forested, on a 5 percent slope at an elevation of 1630 meters. (Colors are for dry soil unless otherwise noted.)
Oi--0 to 2 centimeters; slightly decomposed plant material; strongly acid (pH 5.5); abrupt smooth boundary.
A--2 to 18 centimeters; grayish brown (10YR 5/2) very paragravelly ashy loamy coarse sand, very dark grayish brown (10YR 3/2) moist; weak fine granular structure parts to single grain; loose, nonsticky, nonplastic; many very fine and fine roots throughout; many very fine and fine interstitial pores; 50 percent pumice paragravel; slightly acid (pH 6.4); clear smooth boundary.
C1--18 to 84 centimeters; light gray (2.5Y 7/2) paragravel, grayish brown (2.5Y 5/2) moist; single grain; loose, nonsticky, nonplastic; few very fine and fine, and common very coarse roots throughout; many very fine, fine, and medium interstitial pores; 92 percent pumice paragravel; neutral (pH 6.7); gradual smooth boundary.
C2--84 to 142 centimeters; light gray (2.5Y 7/2) extremely paragravelly ashy loamy sand, grayish brown (2.5Y 5/2) moist; single grain; loose, nonsticky, nonplastic; few very fine, fine, and coarse roots throughout; many very fine, fine, and medium interstitial pores; 80 percent pumice paragravel; neutral (pH 6.7); abrupt smooth boundary.
2Bw--142 to 170 centimeters; yellowish brown (10YR 5/4) ashy loamy sand, dark brown (10YR 3/3) moist; weak coarse subangular blocky structure; slightly hard, friable, nonsticky, nonplastic; very few fine and very fine roots throughout; few very fine and fine interstitial and few fine dendritic tubular pores; 5 percent fine pumice paragravel; neutral (pH 7.1).
TYPE LOCATION: Deschutes County, Oregon; NW 1/4, SW 1/4 section 4, T. 22 S., R. 14 E.; Latitude 43.6958540, Longitude -121.0659090, datum WGS84 (coordinates determined with a GPS).
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--3.7 to 6.7 degrees C
Soil moisture--usually moist in winter and spring, dry in the moisture control section for 45 to 75 days in the 4 months following the summer solstice
Depth to buried soil--greater than 120 cm
Thickness of ash influenced layers--greater than 150 cm
Estimated properties of layers influenced by volcanic ash
Ammonium oxalate extractable Al + Fe--0.4 to 1.6 percent
1500 kPa water content (air dry)--3 to 12 percent
0.02 to 2.0 mm fraction--60 to 95 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--40 to 80 percent
P retention--25 to 50 percent
Particle-size control section: mineral soil surface to 100 cm below the soil surface (2 to 102cm)
Clay content, weighted average--0 to 4 percent
Fragment content, weighted average--60 to 95 percent
A horizon
Hue--10YR or 2.5Y
Value--3 or 4 moist, 4 to 6 dry
Chroma--2 to 4
Fine earth texture--ashy loamy sand, ashy loamy coarse sand or ashy coarse sand
Clay content--0 to 4 percent
Sand content--75 to 100 percent
Organic matter--0.50 to 2.0 percent
Total fragment content--40 to 95 percent
Pumice paragravel--40 to 95 percent
Reaction--6.1 to 6.5 (slightly acid)
Thickness--2 to 16 cm
C horizons
Hue--10YR or 2.5Y
Value--3 to 7 moist, 6 to 8 dry
Chroma--2 to 6
Fine earth texture--ashy loamy sand, ashy loamy coarse sand or ashy coarse sand
Clay content--0 to 4 percent
Sand content--75 to 90 percent
Organic matter--0.0 to 1.0 percent
Total fragment content--60 to 95 percent
Pumice paragravel--60 to 95 percent
Reaction--6.1 to 7.3 (slightly acid to neutral)
Combined thickness of C horizons--85 to 160 cm
2Bw horizon (when present)
Hue--10YR
Value--3 or 4 moist, 4 to 6 dry
Chroma--3 to 6
Fine earth texture--ashy sandy loam, ashy loamy sand or ashy loamy coarse sand
Clay content--2 to 15 percent
Sand content--60 to 85 percent
Organic matter--0.0 to 1.0 percent
Total fragment content--0 to 40 percent
Pumice paragravel (fine)--0 to 15 percent
Gravel--0 to 40 percent
Cobble--0 to 40 percent
Reaction--6.1 to 7.3 (slightly acid to neutral)
Thickness--0 to 60 cm
COMPETING SERIES:
None
GEOGRAPHIC SETTING:
Elevation--1325 to 2000 m
Climate--cold, wet winters and cool, dry summers
Mean annual precipitation--300 to 890 mm
Mean annual air temperature--3.0 to 6.5 degrees C
Frost-free period--20 to 50 days
Lithology--volcanic pumice and ash derived from Newberry Caldera over volcanic ash derived from Mazama
GEOGRAPHICALLY ASSOCIATED SOILS:
Ipsoot--occurs on cinder cones; 50 to 100 cm to cinder
Klawhop--occurs on lava flows, lava plains and mountain slopes; 25 to 50 cm to lithic contact
Lapine--occurs on lava plains; averages 35 to 60 percent pumice paragravel in the particle-size control section
Norwicki--occurs on lava flows lava plains and mountain slopes; 50 to 100 cm to lithic contact
Timbercrater--occurs on mountain slopes, ridges, and buttes; averages less than 60 percent pumice paragravel in the particle-size control section; soil moisture control section dry for less than 45 dry days following the summer solstice (udic soil moisture regime)
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage--excessively drained
Saturated hydraulic conductivity (Ksat)--high to very high
USE AND VEGETATION:
Use--timber production, wildlife habitat
Vegetation--lodgepole pine, Ponderosa pine, greenleaf manzanita, antelope bitterbrush, western needlegrass
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 derived from Moffitt Road in the Deschutes National Forest
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Particle-size control section--2 to 102 cm (A, C1, and part of the C2 horizon)
Ochric epipedon--2 to 18 cm (A horizon)
Andic soil properties--2 to 170 cm (A, C1, C2, and 2Bw horizons)
National Cooperative Soil Survey
U.S.A.