LOCATION CORNGREEN OR
Tentative Series
JRD
12/2024
CORNGREEN SERIES
Landscape--mountains, plateaus
Landform--snow pockets and snow chutes on mountain sideslopes, drainageways, benches and terraces
Slope--10 to 50 percent
Parent material--residuum and colluvium derived from andesite, andesitic tuffs or andesitic basalt with an influence of volcanic ash in the surface
Mean annual precipitation--about 710 mm
Mean annual air temperature--5 degrees C
Depth class--very deep
Drainage class--somewhat poorly drained
Soil moisture regime--xeric
Soil temperature regime--cryic
Soil moisture subclass--oxyaquic
TAXONOMIC CLASS: Very-fine, smectitic Vitrandic Argicryolls
TYPICAL PEDON: Corngreen ashy sandy clay loam - rangeland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 8 cm (0 to 3 inches); very dark grayish brown (10YR 3/2) ashy sandy clay loam, very dark brown (10YR 2/2) moist; strong medium granular structure; soft, friable, slightly sticky and non- plastic; many very fine to medium roots; many very fine and fine vesicular pores; neutral (pH 6.8); abrupt smooth boundary.
A2--8 to 18 cm (3 to 7 inches); very dark grayish brown (10YR 3/2 ) ashy sandy clay loam, very dark brown (10YR 2/2) moist; weak coarse platy parting to weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine to coarse roots; many very fine and fine irregular pores; about 5 percent gravel and 5 percent cobble; neutral (pH 7.0); clear wavy boundary.
A3--18 to 38 cm (7 to 15 inches); very dark grayish brown (10YR 3/2) ashy sandy clay loam, very dark brown (10YR 2/2) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, sticky and slightly plastic; many very fine to coarse roots; common very fine and fine irregular pores; about 5 percent gravel and 5 percent cobble; neutral (pH 6.8); clear smooth boundary
Bw--38 to 58 cm (15 to 23 inches); very dark grayish brown (10YR 3/2) ashy silty clay loam, very dark brown (10YR 2/2) moist; strong fine and medium subangular blocky structure; hard, firm, very sticky and slightly plastic; common fine through coarse roots; common very fine and fine interstitial pores; about 5 percent gravel and 5 percent cobble; neutral (pH 7.0); abrupt smooth boundary
2Bt1--58 to 86 cm (23 to 34 inches); mixed matrix of very dark grayish brown (10YR 3/2) and black (10YR 2/1) clay, very dark brown (10YR 2/2) and black (10YR 2/1) moist; black portion of matrix appears to be stained by organic matter; strong fine and medium angular blocky structure; very hard, very firm, very sticky and very plastic; many distinct clay films on faces of peds and on rock fragments; about 5 percent gravel, neutral (pH 6.8); abrupt smooth boundary
2Bt2--86 to 112 cm (34 to 44 inches); dark brown (7.5YR 3/2) clay, very dark brown (7.5YR 2.5/2) moist; strong fine and medium angular blocky structure; very hard, very firm, very sticky and very plastic; common very fine and fine tubular pores; many patchy distinct clay films on faces of peds, lining pores and on rock fragments; about 10 percent andesitic tuff para-gravels, neutral (pH 6.8)
3Bt3--112 cm to 152 cm (44 to 60 inches); very dark brown (7.5YR 2.5/3) very cobbly clay, very dark brown (7.5YR 2.5/2) moist; strong fine angular blocky structure; very hard, very firm, very sticky and moderately plastic; few very fine and fine interstitial pores; many patchy distinct clay films on faces of peds, lining pores and on rock fragments; about 20 percent gravel and 30 percent cobbles; neutral (pH 6.8)
TYPE LOCATION: Crook County, Oregon; off the 4200-200 road about 2.5 km down from the Round Mountain summit; ca 915 m NE of the top of Round Mountain in the Ochoco National Forest; southwestern Blue Mountains; about 486 m north and 579 m west for the SW corner of section 33; T13 S., R24 E; Ochoco Butte, Oregon, USGS 7.5 minute topographic quadrangle; latitude 44 degrees, 23 minutes and 49.3 seconds N; longitude 120 degrees, 20 minutes, 19.6 seconds; NAD 1983 Datum; (coordinates determined with a GPS)
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--3.8 to 5.0 degrees C
Soil moisture control section--usually moist in winter, spring and early summer, dry in all parts at least 45 consecutive days following the summer solstice (July and August); the soil is episaturated through the upper 58 cm during the spring for at least 20 consecutive days during normal years, xeric soil moisture regime
Depth to lithic contact--> 150 cm
Thickness of mollic epipedon--40 to 100cm
Estimated properties of layers influenced with volcanic ash
*Vitrandic feature thickness- 30 to 80 cm
*Acid oxalate extractable Al+1/2Fe--0.4 to 1.0 percent
*Volcanic glass content--20 to 30 percent
Particle-size control section
*Clay content-- > 65 percent
*Total rock fragments--0 to 10 percent
*Angular andesite and andesitic tuff gravel--0 to 10 percent, typically in lower part of profile
A horizons
Hue--10YR or 7.5YR
Value--3 or 4 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist
Texture--ashy sandy clay loam, ashy loam
Clay content--20 to 30 percent.
OM--2.0 to 6.0
Rock Fragments--0 to 10 percent
Reaction--slightly acid to neutral
Bw horizon
Hue--10YR or 7.5YR
Value: 3 or 4 dry, 2 or 3 moist
Chroma: 2 or 3, dry or moist
Texture--ashy sandy clay loam, ashy silty clay loam or clay loam
Clay content--27 to 40 percent, generally increasing with depth from the overlying horizon.
OM--1 to 4
Rock fragments--0 to 20 percent andesitic para-gravels
Reaction--slightly acid to neutral
Bt horizons
Hue--7.5YR or 10YR
Value--2, 2.5 or 3 dry, 2 or 2.5 moist.
Chroma--1 to 3, dry or moist.
Texture--heavy clay
Clay content--55 to 70 percent.
OM--0.5 to 1.5
Rock fragments--5 to 50 percent at depth, dominantly andesitic gravel and cobble
Reaction--slightly acid to neutral
COMPETING SERIES:
No competing series
GEOGRAPHIC SETTING:
Elevation--1640 to 2050 meters
Climate--cool, dry summers; cold, wet winters
Mean annual precipitation--510 to 850 mm
Mean annual air temperature--3 to 6 degrees C
Frost-free period--30 to 60 days
Lithology-- ashy loamy and silty alluvium over clayey andesitic, tuffaceous and basaltic residuum
GEOGRAPHICALLY ASSOCIATED SOILS:
Chochoco--occurs on benches, ridges and side slopes; 50 to 100 cm to lithic contact; rangeland
Hoffman--occurs on mountain sideslopes and benches; 100 to 150 cm to lithic contact; andic properties; forested
Spanoch--occurs on mountain side slopes and benches; 100 to 150 cm to lithic contact; 18 to 36 cm of volcanic ash in surface; forested
Wolfwire--occurs on mountain side slopes; udic moisture regime; 50 to 100 cm to lithic contact; andic properties; forested
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--somewhat poorly drained
Saturation during normal years--common in winter and spring
Flooding--none
Ponding--none
Saturated hydraulic conductivity (Ksat)--moderately high in surface, low in subsurface
USE AND VEGETATION:
Use--rangeland, wildlife habitat and water supply
Natural vegetation--hellebore, cow parsnip, horsemint, goldenrod and mountain brome
Plant Association--FW50, Hellebore Wetlands
DISTRIBUTION AND EXTENT:
Distribution--Central Oregon
MLRA--43, Blue Mountains, B10XY
Extent--moderate
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: Crook County, (Ochoco National Forest) Oregon, 2017. The name is coined
REMARKS:
Diagnostic horizons and other features in this pedon
*Particle-size control section--zone from 58 to 108 cm
*Mollic epipedon--zone from 0 to 58 cm
*Vitrandic feature--zone from 0 to 58 cm
*Depth to lithic contact--over 150 cm
________________________________________
National Cooperative Soil Survey
U.S.A.