LOCATION OHARSEVEN               OR

Tentative Series
Rev. CEG
02/2025

OHARSEVEN SERIES

Landscape--intermontane basin
Landform--alluvial fans, flood-plain steps
Slope--0 to 4 percent
Parent material--slope alluvium derived from mudstone, basalt and/or andesite with an influence of volcanic ash in the upper part
Mean annual precipitation--about 700 mm
Mean annual air temperature--about 6 degrees C
Depth class--moderately deep
Drainage class--moderately well drained
Soil moisture regime--xeric
Soil temperature regime--frigid
Soil moisture subclass--typic

TAXONOMIC CLASS: Clayey over loamy-skeletal, smectitic over mixed, superactive, frigid Abruptic Haplic Durixeralfs

TYPICAL PEDON: Oharseven ashy loam, grassland, on a 3.0 percent slope at 1525 m elevation.

A--0 to 7 cm; ashy loam, light gray (2.5Y 7/1) dry, very dark gray (10YR 3/1) moist; strong very coarse subangular blocky parting to moderate thin platy structure; moderately hard, very friable, slightly sticky and nonplastic; common very fine and fine roots; few fine dendritic tubular pores; 2 percent gravel and 1 percent cobbles; noneffervescent; slightly acid (pH 6.4); clear smooth boundary

AB--7 to 25 cm; ashy clay loam, gray (10YR 6/1) dry, very dark grayish brown (10YR 3/2) moist; strong medium subangular blocky parting to moderate thick platy structure; moderately hard, friable, moderately sticky and slightly plastic; many very fine and fine and few medium and coarse roots; common fine dendritic tubular pores; 10 percent gravel and 2 percent cobbles; noneffervescent; slightly acid (pH 6.5); clear smooth boundary

2Btss--25 to 52 cm; clay, brown (10YR 5/3) dry, brown (10YR 4/3) moist; strong coarse prismatic structure; very hard, firm, moderately sticky and very plastic; few very fine, fine and coarse roots; few fine dendritic tubular pores; 15 percent slickensides on all faces of peds and 40 percent prominent clay films on rock fragments and on all faces of peds; vertical cracks 2 to 5 cm wide, 6 to 10 cm apart that do not extend to the surface; 5 percent gravel; noneffervescent; neutral (pH 7.0); gradual smooth boundary

3Btqm--52 to 60 cm; very gravelly sandy clay loam, light gray (10YR 7/2)dry, brown (10YR 4/3) moist; moderate medium angular blocky structure; moderately hard, friable, weakly coherent by silica, slightly sticky and slightly plastic; 30 percent prominent clay films on rock fragments and on all faces of peds; 10 percent silica masses around rock fragments and in matrix; 35 percent gravel, 10 percent cobbles, 1 percent stones, and 10 percent medium to coarse durinodes; noneffervescent; neutral (pH 7.2); clear smooth boundary

3Btkqm--60 to 78 cm; extremely gravelly loam, light yellowish brown (10YR 6/4) dry, dark yellowish brown (10YR 4/4) moist; weak medium subangular blocky structure; extremely hard, very firm, weakly coherent by silica, slightly sticky and slightly plastic; 5 percent prominent clay films on rock fragments and on all faces of peds; 1 percent fine spherical strongly coherent iron-manganese concretions in matrix; 1 percent carbonate masses in matrix; 1 percent salt masses in matrix; 5 percent silica masses in matrix and around rock fragments; 50 percent gravel, 15 percent cobbles, and 1 percent stones; slight effervescence; slightly alkaline (pH 7.6); clear smooth boundary

3Btqm--78 to 100 cm; extremely cobbly cemented material, very pale brown (10YR 7/4)dry, brownish yellow (10YR 6/6) moist; very rigid, strongly coherent by silica; 2 percent prominent clay films on rock fragments and on all faces of peds; 2 percent fine spherical strongly coherent iron-manganese concretions in matrix; 10 percent silica masses in matrix; 2 percent stones and 30 percent gravel and 35 percent cobbles; noneffervescent; slightly alkaline (pH 7.6)

TYPE LOCATION: Klamath County, Oregon; about 6.9 miles south and 1.0 mile east of the town of Chiloquin, Oregon; about 427 m north and 469 m west of the southeast corner of Section 2, Township 36 S, Range 7 E; Willamette Meridian; Modoc Point, Oregon U. S. Geological Survey quadrangle; latitude 42.4755833 degrees north, longitude 121.8437500 degrees west, datum WGS 84 (coordinates derived from GPS unit)
RANGE IN CHARACTERISTICS:

Mean annual soil temperature--6.0 to 8.0 degrees C
Moisture control section--10 to 30 cm; xeric regime; dry in all parts for 60 to 90 days in the four month period following the summer solstice; seasonally high water table (episaturation) has an upper limit between 10 and 75 cm below the surface, for less than 60 days in March or April in normal years, but is absent in drier years
Rock fragments--volcanic rock gravel, dominantly andesite or basalt
Thickness of materials influenced by volcanic ash (A and AB horizons)--15 to 75 cm
Depth to argillic horizon (and lithologic discontinuity with clayey materials)--15 to 75 cm
Depth to strongly coherent duripan--50 to 100 cm
Depth to lithologic discontinuity with skeletal materials (the top of the 3Btqm horizon)--50 to 100 cm

Particle-size control section
*Clay content--35 to 65 percent, upper part; 18 to 38 percent, lower part
*rock fragment content--0 to 10 percent, upper part; 35 to 70 percent, lower part

Estimated properties, horizons meeting vitrandic subgroup criteria (A and AB horizons):
*Ammonium oxalate extractable Al plus 1/2 Fe--0.2 to 0.7 percent
*Medium to very coarse sand in the .02 to 2.0 mm fraction--less than 50 percent
*P-retention--3 to 20 percent
*Volcanic glass content--5 to 20 percent glass and glass-coated aggregate
*1/3-bar bulk density--1.00 to 1.20 g/cm3
*1500 kPa water (air-dried samples)--10 to 25 percent

A horizons
Hue--10YR or 2.5Y, moist or dry
Value--2 or 3 moist, 4 to 7 dry
Chroma--1 to 3, moist or dry
Clay content--15 to 27 percent
Total rock fragment content--0 to 14 percent
Gravel content--0 to 14 percent
Cobble content--0 to 2 percent
Organic matter content--2 to 10 percent
Reaction--slightly acid to neutral (pH 6.1 to 7.3)
Thickness--6 to 12 cm

AB horizons
Hue--10YR or 2.5Y, moist or dry
Value--2 or 3 moist, 4 to 7 dry
Chroma--1 to 3, moist or dry
Fine-earth texture--ashy loam, ashy sandy clay loam, ashy clay loam
Clay content--15 to 35 percent
Total rock fragment content--0 to 14 percent
Gravel content--0 to 14 percent
Cobble content--0 to 2 percent
Organic matter content--0.4 to 4 percent
Reaction--slightly acid to neutral (pH 6.1 to 7.3)
Thickness--13 to 65 cm

2Btss horizon
Hue--7.5YR or 10YR, moist or dry
Value--3 to 5 moist, 5 to 7 dry
Chroma--2 to 4 moist or dry
Fine-earth texture--silty clay loam, clay loam, silty clay, clay
Clay content--35 to 65 percent
Gravel content--0 to 10 percent
Organic matter content--0.5 to 2 percent
Reaction--slightly acid to neutral (pH 6.1 to 7.3)
Thickness--10 to 30 cm

3Btqm and 3'Btqm horizons
Hue--10YR or 2.5Y, moist or dry
Value--3 to 5 moist, 5 to 7 dry
Chroma--2 to 4, moist or dry
Fine-earth texture--loam, sandy clay loam, clay loam, cemented material
Coherence--weak to very strongly
Clay content--20 to 38 percent
Total rock fragment content--5 to 70 percent
Durinode content--0 to 30 percent
Gravel content--0 to 65 percent
Cobble content--0 to 12 percent
Stone content--0 to 5 percent
Organic matter content--0.1 to 1 percent
Reaction--neutral (pH 6.6 to 7.3)
Thickness--greater than 10 cm (cumulative)

3Btkqm horizons (where present)
Hue--10YR or 2.5Y, moist or dry
Value--3 to 5 moist, 5 to 7 dry
Chroma--2 to 4, moist or dry
Fine-earth texture--sandy loam, loam, sandy clay loam
Coherence--weak
Clay content--10 to 27 percent
Total rock fragment content--35 to 70 percent
Durinode content--0 to 30 percent
Gravel content--35 to 65 percent
Cobble content--0 to 30 percent
Stone content--0 to 5 percent
Organic matter content--0.1 to 1 percent
Reaction--neutral to slightly alkaline (pH 6.6 to 7.8)
Thickness--0 to 25 cm

COMPETING SERIES:
There are no competing series

GEOGRAPHIC SETTING:
Elevation--1280 to 1800 m
Climate--cold, moist winters and cool, dry summers
Mean annual air temperature-- 4 to 7 degrees C
Mean annual precipitation--430 to 980 mm
Frost-free period--55 to 70 days

GEOGRAPHICALLY ASSOCIATED SOILS:
Maset--on low hills, rock pediments, dip slopes, and volcanic fields; moisture control section is unsaturated throughout the year (well drained); ochric epipedon; frigid soil temperature regime; contact with tuffaceous sandstone between 50 and 100 cm (moderately deep)
Teleflat--on flood plains; seasonal high water table and redoximorphic features within 5 to 50 cm of the soil surface (poorly drained); mollic epipedon 50 to 90 cm thick; fine particle size class
Ontko--on flood plains; seasonal high water table and redoximorphic features at the soil surface (poorly drained); endosaturation only (no episaturation); mollic epipedon less than 50 cm thick; fine-loamy particle-size class
Spragueriver--on drainageways and flood plains; seasonal high water table and redoximorphic features at the soil surface (poorly drained); endosaturation (no episaturation); mollic epipedon greater than 100 cm thick; fine-loamy particle-size class

DRAINAGE AND PERMEABILITY:
Drainage class--moderately well drained
Saturation in normal years--episaturation above clayey textures (the 2Btss horizon) with an upper limit between 10 and 75 cm from the soil surface, for less than 60 days in March or April
Saturated hydraulic conductivity (Ksat)--moderately high to high in the A and AB horizons; moderately low to moderately high in the 2Btss horizon; moderately high to high in the 3Btqm and 3Btkqm horizons; low in the strongly coherent duripan (3'Btqm horizon)

USE AND VEGETATION:
Use--native meadow pasture, rangeland, and wildlife
Vegetation--California oatgrass, annual hairgrass, bottlebrush squirreltail, Cusick's bluegrass, Sandberg bluegrass

DISTRIBUTION AND EXTENT: Cascade Mountains, Eastern Slope, Oregon; MLRA 6; small extent

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

SERIES PROPOSED:
Klamath County, Oregon, 2012
Origin of the name--the name is coined

REMARKS:
Diagnostic horizons and features in this pedon
*Ochric epipedon
*Volcanic glass--zone from 0 to 25 cm
*Particle-size control section--zone from 25 to 75 cm
*Argillic horizon--zone from 25 to 100 cm
*Depth to lithologic discontinuities--25 cm, 52 cm
*Abrupt textural change--25 cm
*Duripan--zone from 52 to 100 cm

NASIS Site ID--11OR035007
NASIS Pedon ID--S2012OR035001

ADDITIONAL DATA:
Kellogg Soil Survey Laboratory (KSSL) analyses on A, AB, and 2Btss horizons--12N8331

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National Cooperative Soil Survey
U.S.A.