LOCATION NIBOLOB ORTentative Series
TAXONOMIC CLASS: Fine-loamy, isotic, frigid Vitrandic Argixerolls
TYPICAL PEDON: Nibolob ashy silt loam - forest, on an 18 percent southfacing slope at 3,275 feet elevation. (Colors are for moist soil unless otherwise noted.)
Oi--0 to 2 inches; slightly decomposed needles, twigs, and leaves
A--2 to 7 inches; very dark brown (7.5YR 2.5/2) ashy silt loam, dark grayish brown (10YR 4/2) dry; moderate medium and fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine, common fine roots; common very fine irregular pores; neutral (pH 6.7); clear wavy boundary. (5 to 6 inches thick)
AB--7 to 17 inches; very dark brown (10YR 2/2) ashy loam, brown (10YR 4/3) dry; moderate coarse subangular blocky parting to moderate and fine subangular blocky structure; hard, friable, slightly sticky and slightly plastic; few very fine, common fine, common medium and few coarse roots; common fine irregular and few fine tubular, few medium tubular pores; slightly acid (pH 6.5); clear wavy boundary. (6 to 10 inches thick)
Bt1--17 to 29 inches; dark brown (10YR 3/3) clay loam, yellowish brown (10YR 5/4) dry; weak coarse subangular blocky structure parting to moderate medium and fine angular blocky; hard, firm, moderately sticky and moderately plastic; common faint clay films on faces of peds and few distinct clay films lining tubular pores; few fine and coarse, and common medium roots; few very fine tubular pores; slightly acid (pH 6.5); gradual, smooth boundary. (5 to 23 inches thick)
Bt2--29 to 57 inches; dark grayish brown (10YR 4/2) clay loam, yellowish brown (10YR 5/4) dry; weak medium and fine subangular blocky structure; slightly hard, friable, very sticky and very plastic; few faint clay films found on faces of peds; few fine, few medium, few coarse roots; few very fine tubular pores; 10 percent gravel; slightly acid (pH 6.5); (13 to 32 inches thick)
R--57 inches; basalt bedrock
TYPE LOCATION: Grant County, Oregon
Section 20 (NW , NW , SE ), T. 8S., R. 27E.
Latitude: 44 deg 51 min, 33 sec N; Longitude: 119 deg, 31 min, 12 sec W
UTM Zone 11; 4,970,170 northing; 300,890 easting; NAD 27
USGS Quadrangle: Bologna Basin
RANGE IN CHARACTERISTICS:
Soil Temperature: frigid regime
Mean Annual Soil Temperature: 44 to 47 degrees F
Mean Summer Soil Temperature: 53 to 58 degrees F
Mean Winter Soil Temperature: 34 to 38 degrees F
Soil Moisture: xeric regime, dry 60 to 75 days in summer
Particle-size Control Section: upper 20 inches of argillic horizon
Clay content, average: 19 to 35 percent
Rock fragment content, average: 5 to 15 percent
Diagnostic Horizons and Features:
Vitrandic subgroup properties: from mineral surface, 12 to 26 inches thick
Al+1/2Fe (ammonium oxalate): 0.2 to 0.7 percent
bulk density: 0.85 to 1.0 g/cc
P retention: 25 to 45 percent
0.02-2.0 mm fraction: 30 to 50 percent of fine earth
glass content in the 0.02-2.0mm fraction: 15 to 30 percent
8Si + 2Fe (ammonium oxalate): 1 to 5
mollic epipedon: 20 to 30 inches thick
argillic layer: 12 to 34 inches thick
lithic contact, depth from mineral soil surface: 40 to 60 inches
A horizon:
color, moist: 7.5YR 2.5/2, 3/2; 10YR 2/2
color, dry: 7.5YR 4/2, 5/3; 10YR 3/3, 4/3
texture: ASHY-SIL, ASHY-L
clay content: 8 to 18 percent
rock fragment content: 0 to 5 percent gravel
reaction: neutral; pH: 6.6 to 7.3.
base saturation: 85 to 100 percent (ammonium acetate)
AB horizon:
color, moist: 7.5YR 2.5/2, 3/2; 10YR 2/2
color, dry: 7.5YR 4/3, 5/3; 10YR 3/3, 4/3
texture: ASHY-L, ASHY-SIL
clay content: 18 to 25 percent
rock fragment content: 0 to 5 percent gravel
reaction: slightly acid to neutral; pH: 6.1 to 7.3
base saturation: 85 to 100 percent (ammonium acetate)
Bt1 horizon:
color, moist: 7.5YR 2.5/3, 3/2, 3/3; 10YR 3/3
color, dry: 7.5YR 4/3, 4/4, 5/4; 10YR 4/4, 5/4
texture: CL, L, GR-L
clay content: 18 to 35 percent
rock fragment content: 0 to 15 percent total
gravel: 0 to 15 percent
cobbles:0 to 5 percent
reaction: slightly acid to neutral; pH: 6.1 to 7.3
base saturation: 85 to 100 percent (ammonium acetate)
Bt2 horizon:
color, moist: 7.5YR 4/3; 10YR 4/2
color, dry: 7.5YR 5/4; 10YR 4/4, 5/4
texture: CL, L, CB-L
clay content: 14 to 33 percent
rock fragment content: 5 to 25 percent total
gravel: 5 to 15 percent
cobbles: 0 to 10 percent
reaction: slightly acid to neutral; pH: 6.1 to 7.3
base saturation: 85 to 100 percent (ammonium acetate)
COMPETING SERIES:
Bly: deep and very deep (40 to greater than 60 inches) to a duripan, dry 60 to 90 days in summer
Bolobin: moderately deep (20 to 40 inches) to a lithic contact (basalt); formed in a mixed mantle of volcanic ash and loess over colluvium from basalt; mixed mantle has 15 to 30 percent volcanic glass; more than 15 percent rock fragments in lower part of the argillic horizon
Bolony: moderately deep (20 to 40 inches) to a lithic contact (basalt); formed in loess with a minor influence of volcanic ash over colluvium from basalt; volcanic glass in surface layers is 5 to 15 percent; more than 15 percent rock fragments in lower part of the argillic horizon
Forbord: deep and very deep (40 to greater than 60 inches) to a lithic contact; formed in a mixed mantle of volcanic ash and loess over colluvium from basalt, ryholite, tuff or marine sediments; mixed mantle, 7 to 10 inches thick, has andic soil properties with 30 to 50 percent volcanic glass; mollic epipedon is 20 to 40 inches thick; dry 75 to 90 days in summer
Forshey: very deep (lacks a lithic contact within 60 inches); formed in a mixed mantle of volcanic ash and loess over colluvium from granitic rocks; mixed mantle has 15 to 30 percent volcanic glass; buried 2E horizon below mollic epipedon; rock fragments in subsoil are subrounded gravel
Hess: deep (40 to 60 inches) to a lithic contact (tuff); mollic epipedon is 10 to 20 inches thick; particle-size control section has 0 to 15 percent rock fragments and 5 to 50 percent pararock fragments; dry 45 to 75 days in summer
Lidos: very deep (lacks a lithic contact within 60 inches); formed in colluvium from basalt with an influence of volcanic ash in upper part of solum, over alluvium from pyroclastic materials; has 5 to 20 percent glass in volcanic ash influenced mantle; buried genetic horizons developed in pyroclastic alluvium at 30 to 60 inches; dry 45 to 75 days in summer
Melhorn: very deep (lacks a lithic contact within 60 inches); formed in a mixed mantle of volcanic ash and loess over colluvium from basalt; mixed mantle has 20 to 30 percent volcanic glass; subsoil has angular or subangular rock fragments including cobbles; 45 to 75 dry days in summer
Raycreek: moderately deep (20 to 40 inches) to a lithic contact (tuff); formed in a mantle of colluvium mixed with volcanic ash over residuum from metasedimentary rock; volcanic glass in surface layers is 10 to 30 percent; less than 15 percent rock fragments in the argillic horizon
Salcreek: very deep (lacks a lithic contact within 60 inches); formed in metasedimentary till with a minor influence of volcanic ash in horizons above the till; ash influenced surface horizons have 5 to 20 percent volcanic glass; particle-size control section has more than 50 percent sand
Spartabutte: moderately deep (20 to 40 inches) to a lithic contact (granite); formed in loess with a minor influence of volcanic ash over colluvium from granitic rock; volcanic glass in surface layers is 5 to 15 percent; mollic epipedon is 10 to 18 inches thick
Vangoe: deep (40 to 60 inches) to a lithic contact (basalt); mollic epipedon is 20 to 30 inches thick; dry 45 to 60 days in summer
GEOGRAPHIC SETTING:
Landform: lower backslopes, footslopes and toeslopes of mountains
Slope gradient: 0 to 60 percent
Parent material: Mazama volcanic ash and loess, overlying colluvium
Lithology: basalt
Elevation: 3,200 to 4,200 feet
Climate: cold, wet winters and cool, dry summers
Mean annual precipitation: 19 to 25 inches
Mean annual air temperature: 42 to 45 degrees F
Frost-free period: 50 to 125 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Bocker: on shoulders and plateau summits; very shallow soil without an argillic horizon; minor ash influence under sagebrush, Idaho fescue or bluebunch wheatgrass
Bolobin: on gently sloping plateau surfaces; moderately deep to bedrock; mixed ash mantle under Douglas-fir or ponderosa pine forest
Bolony: on scarp slopes of dissected basalt plateaus; moderately deep with an argillic horizon, minor influence of ash under Douglas-fir or ponderosa pine with pinegrass, elk sedge or common snowberry in the understory
Fivebit: on plateaus and backslopes, shallow to bedrock with a minor influence of volcanic ash in loamy-skeletal colluvium under scattered ponderosa pine, Douglas-fir or western juniper with big sage and Idaho fescue
DRAINAGE AND PERMEABILITY:
Drainage: well drained
Permeability: moderately slow
USE AND VEGETATION:
Use: timber production, watershed, wildlife, recreation, livestock grazing
Potential native vegetation; Douglas-fir, ponderosa pine, western juniper, common snowberry, low Oregongrape, heartleaf arnica, woods strawberry, common yarrow, silky lupine, white hawkweed, pinegrass, elk sedge, mountain brome, western fescue, Idaho fescue and bluebunch wheatgrass.
Ecological sites: Dominant: PSME/SYAL (Douglas-fir/common snowberry); may include: PIPO/SYAL (ponderosa pine/common snowberry)
DISTRIBUTION AND EXTENT:
Distribution: MLRA E43c; Central Blue Mountains in northeastern Oregon
Extent: small
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES PROPOSED: Grant County, Oregon. Name is coined.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
mollic epipedon: 2 to 29 inches; A, AB, and Bt1 horizons
argillic layer: 17 to 57 inches; Bt1 and Bt2 horizons
vitrandic subgroup feature: 2 to 17 inches; A and AB horizons
particle-size control section: 17 to 37 inches; Bt1 and Bt2 horizons
ADDITIONAL DATA: NSSL Pedon ID: 99OR 023005