LOCATION MOLAWA OR
Tentative Series
Rev. JMW/CEG/TDT
02/2025
MOLAWA SERIES
Landscape--Cascade Mountains
Landform--mountain slopes, glaciated hillslopes, ground moraines
Slope--0 to 35
Parent material--colluvium, till, and residuum derived from basalt and andesite mixed with volcanic ash throughout
Mean annual precipitation--about 1020 mm
Mean annual air temperature--about 5.5 degrees C
Depth class--very deep
Drainage class--well drained
Soil moisture regime--udic
Soil temperature regime--cryic
Soil moisture subclass--typic
TAXONOMIC CLASS: Medial, amorphic Typic Haplocryands
TYPICAL PEDON: Molawa medial loam in coniferous forest, on a southwest facing slope of 8 percent, with 0.03 percent surface stones and 0.01 percent surface boulders, at an elevation of 2012 m. When described on September 1, 2010, the soil was dry throughout. (All textures are apparent field textures.)
Oi--0 to 2 cm; slightly decomposed needles and twigs; abrupt smooth boundary
Oe--2 to 6 cm; moderately decomposed needles and twigs; abrupt smooth boundary
A--6 to 25 cm; medial loam, dark yellowish brown (10YR 3/4) dry, very dark brown (7.5YR 2.5/3) moist; moderate fine granular structure; very friable, soft, nonsticky and nonplastic; common very fine and fine roots and few medium roots; few fine dendritic tubular pores; 1 percent stones, 2 percent cobbles and 10 percent gravel; slightly acid (pH 6.5); gradual wavy boundary
Bw1--25 to 45 cm; medial loam, brown (10YR 4/3) dry, brown (7.5YR 4/4) moist; weak medium subangular blocky structure; very friable, soft, nonsticky and nonplastic; common very fine, fine and medium roots and few coarse and very coarse roots; few fine dendritic tubular pores; 1 percent stones, 1 percent cobbles and 5 percent gravel; slightly acid (pH 6.5); gradual wavy boundary
Bw2--45 to 90 cm; gravelly medial loam, dark yellowish brown (10YR 4/4) dry, dark brown (7.5YR 3/4) moist; weak medium subangular blocky structure; very friable, soft, nonsticky and nonplastic; few fine, medium, coarse and very coarse roots and common very fine roots; few fine dendritic tubular pores; 2 percent stones, 5 cobbles and 15 percent gravel; slightly acid (pH 6.5); gradual wavy boundary
BC--90 to 206 cm; very gravelly medial loam, yellowish brown (10YR 5/4) dry, dark brown (7.5YR 3/4) moist; massive; very friable, soft, nonsticky and nonplastic; few very fine, fine, medium and coarse roots; few fine dendritic tubular pores; 2 percent stones, 10 percent cobbles and 45 percent gravel; slightly acid (pH 6.5)
TYPE LOCATION: Klamath County, Oregon; about 11.2 miles north and 7.8 miles west of Keno; about 477 m north and 729 m east of the southwest corner of sec. 2, T. 38 S., R. 6 E, Willamette Meridian; Aspen Lake, Oregon U.S. Geological Survey quadrangle (Latitude 42.2903252 degrees, Longitude -122.0818176 degrees, datum WGS 84 (coordinates determined with a GPS device).
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--5.0 to 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--10.0 to 14.4 degrees C
Mean winter soil temperature--2.8 to 5.6 degrees C
Moisture control section--dry for 30 to 45 consecutive days
Depth to restriction--over 200 cm
*Surface Stones--0.0 to 0.1 percent
*Surface Boulders--0.0 to 0.1 percent
*Reaction--slightly acid or moderately acid throughout
*Base Saturation--35 to 60 percent in mineral horizons, 6 to 206 cm
Thickness of volcanic ash influenced layers--100 to over 200 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 and BC 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
Particle-size control section
*Clay--10 to 18 percent clay, weighted average
*Sand--40 to 75 percent sand, weighted average; less than 50 percent of the 0.02 to 0.20 mm fraction is medium to very coarse sand
*Total fragments--10 to 25 percent
O horizons:
*Oe horizons not present in all pedons
*Thickness--3 to 8 cm
A horizon:
*Hue--10YR, 7.5YR, 5YR
*Value--2.5 or 3 moist, 3 to 5 dry
*Chroma--1 to 3 moist, 3 or 4 dry
*Clay--10 to 20 percent
*Sand--30 to 53 percent
*Organic matter--2.0 to 10.0 percent
*Total fragments --5 to 14 percent
*Gravel--2 to 14 percent
*Cobbles--0 to 5 percent
*Stones--0 to 1 percent
*Thickness--6 to 24 cm
A2 horizon (when present):
*Hue--10YR, 7.5YR, 5YR
*Value--2.5 or 3 moist, 3 to 5 dry
*Chroma--1 to 3 moist, 3 or 4 dry
*Fine-earth texture--medial silt loam, medial loam, medial sandy loam
*Clay--5 to 25 percent
*Sand--35 to 75 percent
*Organic matter--2.0 to 10.0 percent
*Total fragments--15 to 25 percent
*Gravel--15 to 20 percent
*Cobbles--0 to 5 percent
*Stones--0 to 2 percent
*Thickness--0 to 24 cm
Bw horizons:
*Hue--10YR, 7.5YR, 5YR
*Value--3 or 4 moist, 4 to 6 dry
*Chroma--3 or 4 moist, 3 to 6 dry
*Fine-earth texture--medial loam, medial sandy loam
*Clay--5 to 25 percent
*Sand--35 to 75 percent
*Organic matter--0.1 to 2.0 percent
*Total fragments--5 to 22 percent
*Gravel--5 to 15 percent
*Cobbles--0 to 5 percent
*Stones--0 to 2 percent
*Thickness--50 to 150 cm
BC horizon:
*Hue--10YR, 7.5YR, 5YR
*Value--3 or 4 moist, 4 to 6 dry
*Chroma--3 or 4 moist, 3 to 6 dry
*Fine-earth texture--medial loam, medial sandy loam
*Clay--5 to 20 percent
*Sand--40 to 75 percent
*Organic matter--0.1 to 1.0 percent
*Total fragments--20 to 60 percent
*Gravel--15 to 45 percent
*Cobbles--5 to 10 percent
*Stones--0 to 5 percent
COMPETING SERIES:
Cruiser--lower glass; 1/3-bar bulk density 0.75 to 0.85; 20 to 30 percent clay
Keel--50 to 100 cm to bedrock; umbric epipedon; 18 to 32 percent clay; less than 40 percent sand
Longbow--1/3-bar bulk density 0.6 to 0.9; umbric epipedon; 18 to 27 percent clay; less than 40 percent sand
Oneonta--1/3-bar bulk density 0.6 to 0.9; umbric epipedon; 18 to 35 percent clay in Bw horizons; less than 40 percent sand
Soosap--50 to 100 cm to a paralithic contact; umbric epipedon
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--frigid temperature regime; 35 to 65 percent rock fragments (skeletal) in the particle-size control section
Oatman--35 to 65 percent rock fragments (skeletal) in the particle-size control section
Llaorock--vitric subgroup
Otwin--50 to 100 cm to bedrock; 35 to 65 percent rock fragments (skeletal) in the particle-size control section
Woodcock--argillic horizon; xeric soil moisture regime; frigid temperature regime
Pokegema--xeric soil moisture regime; 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
Overstory vegetation--white fir, Shasta red fir, western white pine
Understory vegetation--mountain brome, western princes pine, sedge
DISTRIBUTION AND EXTENT: Cascade Mountains in southern Oregon; MLRA 3; moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: Klamath County, Oregon, 2015.
REMARKS:
Diagnostic horizons and other features in this pedon
*Particle size control section--6 to 106 cm
*Ochric epipedon
*Andic soil properties--6 to 206 cm
*Volcanic glass--6 to 206 cm
*Cambic horizon--25 to 90 cm
*Udic soil moisture regime based on correlation to Shasta red fir with white fir plant associations and ecological sites.
*Haplocryand--15 bar dry is more than 15 percent throughout
*Medial--Andic soil properties present throughout the particle-size control section; 15 bar water dry is more than 15 percent throughout on dried samples
*Amorphic--The particle-size control section has over 2 percent acid oxalate extractable silica
ADDITIONAL DATA:
*NASIS Site ID--10-CEG-05
*NASIS Pedon ID--10-CEG-05
*Andic soil properties--based on laboratory data from associated Oatman series: NSSL S01OR-035-002, 003, 004 and 005
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.