LOCATION TOMMYCORK ORTentative Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Vitrandic Argixerolls
TYPICAL PEDON: Tommycork ashy silt loam - rangeland, on a 2 percent northfacing slope at an elevation of 4,100 feet. (Colors are for moist soil unless otherwise noted.)
A--0 to 7 inches; dark brown (7.5YR 3/3) ashy silt loam, brown (7.5YR 5/4) dry; weak fine and very fine granular structure; slightly hard, friable, moderately sticky and moderately plastic; many very fine roots throughout; many very fine irregular pores; 3 percent gravel; slightly acid (pH 6.5); clear smooth boundary. (4 to 9 inches thick)
ABt--7 to 19 inches; dark brown (7.5YR 3/3) ashy silt loam, brown (7.5YR 4/4) dry; hard, friable, moderately sticky and moderately plastic; moderate medium subangular blocky structure parting to weak fine subangular blocky; few faint clay films on ped faces and lining tubular or irregular pores; few very fine and medium, and common fine roots throughout; common very fine tubular and irregular, and few fine tubular pores; 1 percent gravel; slightly acid (pH 6.5); clear wavy boundary. (4 to 12 inches thick)
Bt1--19 to 27 inches; dark brown (7.5YR 3/3) clay loam, strong brown (7.5YR 4/6) dry; moderate medium subangular blocky structure parting to moderate fine subangular blocky; hard, firm, very sticky and very plastic; common distinct clay films lining tubular or irregular pores and few distinct clays films on ped faces; common fine and few medium roots throughout; common very fine tubular and irregular pores and few fine tubular pores; 2 percent gravel; slightly acid (pH 6.5); clear wavy boundary. (7 to 16 inches thick)
Bt2--27 to 32 inches; brown (7.5YR 4/4) silty clay loam, strong brown (7.5YR 5/6) dry; moderate medium angular blocky structure parting to moderate fine angular blocky; hard, firm, very sticky and very plastic; many, distinct clay films on ped faces; common fine roots throughout; few very fine tubular and irregular pores; 4 percent gravel; slightly acid (pH 6.5); abrupt wavy boundary. (5 to 13 inches thick)
R--32 inches, basalt
TYPE LOCATION: Morrow County, Oregon
Section 31 (NE , SW , SW ), T. 6 S., R. 27 E.
Latitude: 44 deg, 59 min 55 sec N; Longitude: 119 deg, 32 min, 23 sec W
UTM Zone 11; 4,985,720 northing; 299,830 easting NAD27
USGS Quadrangle: Turner Mountain
RANGE IN CHARACTERISTICS:
Soil Temperature: frigid regime
Mean Annual Soil Temperature: 44 to 46 degrees F
Mean Summer Soil Temperature: 52 to 55 degrees F
Mean Winter Soil Temperature: 34 to 37 degrees F
Soil Moisture: xeric regime, dry 75 to 90 consecutive days in summer
Particle-size Control Section: upper 20 inches of the argillic horizon or to a lithic contact
Clay content, average: 20 to 35 percent
Rock fragment content, average: 0 to 10 percent
Diagnostic Horizons and Features:
vitrandic subgroup material: upper boundary at the mineral soil surface; 8 to 19 inches thick
Al+1/2Fe (ammonium oxalate): 0.3 to 0.8 percent
P retention: 20 to 40 percent
0.02-2.0 mm fraction: 30 to 50 percent of fine earth
glass content in the 0.02-2.0mm fraction: 5 to 15 percent
8Si + 2Fe (ammonium oxalate): 0.5 to 3 percent
mollic epipedon: 20 to 30 inches thick
argillic horizon: 15 to 25 inches thick
lithic contact, depth below mineral surface: 20 to 40 inches
A horizon:
color, moist: 7.5YR 2.5/2, 2.5/3, 3/3; 10YR 2/2
color, dry: 7.5YR 3/2, 4/2, 4/3, 5/4; 10YR 3/2
texture: ASHY-L, ASHY-SIL
clay content: 12 to 18 percent
rock fragment content: 0 to 5 percent gravel
reaction: slightly acid to neutral; pH: 6.1 to 7.3.
base saturation: 75 to 90 percent (ammonium acetate)
ABt horizon: (AB horizon in some pedons)
color, moist: 7.5YR 2.5/2, 2.5/3, 3/3; 10YR 2/2
color, dry: 7.5YR 3/2, 3/4, 4/3, 4/4; 10YR 3/2
texture: ASHY-L, ASHY-SIL
clay content: 18 to 27 percent
rock fragment content: 0 to 5 percent total
gravel: 0 to 5 percent
stones: 0 to 1 percent
reaction: slightly acid to neutral; pH: 6.1 to 7.3.
base saturation: 75 to 90 percent (ammonium acetate)
Bt1 horizon:
color, moist: 7.5YR 2.5/2, 2.5/3, 3/3, 4/3; 10YR 3/2
color, dry: 7.5YR 3/3, 4/4, 4/6; 10YR 4/4
texture: CL, L
clay content: 22 to 35 percent
rock fragment content: 0 to 10 percent total
gravel: 0 to 10 percent
cobbles: 0 to 2 percent
reaction: slightly acid to neutral; pH: 6.1 to 7.3
base saturation: 75 to 90 percent (ammonium acetate)
Bt2 horizon:
color, moist: 7.5YR 2.5/3, 3/2, 3/3, 4/4; 10YR 3/3, 4/3
color, dry: 7.5YR 3/3, 4/4, 5/4, 5/6; 10YR 3/3, 4/4
texture: CL, SICL, L
clay content: 22 to 38 percent
rock fragment content: 0 to 10 percent gravel
reaction: slightly acid to neutral; pH: 6.1 to 7.3
base saturation: 75 to 90 percent (ammonium acetate)
COMPETING SERIES:
Luckycreek: very deep (lacks a lithic contact within 60 inches); secondary carbonates occur below the argillic horizon
Pinney: very deep (lacks a lithic contact within 60 inches); has an O horizon
Powellbutte: moderately deep (20 to 40 inches) to a lithic contact; mollic epipedon 20 to 30 inches thick; volcanic ash influenced mantle with 15 to 30 percent glass and a discontinuity between surface horizons and subsoil; subhorizon in lower part of argillic horizon has 40 to 45 percent clay
Fastjet and Runyon: moderately deep (20 to 40 inches) to a paralithic contact; mollic epipedon 10 to 20 inches thick
GEOGRAPHIC SETTING:
Landform: backslopes of dissected basalt plateaus
Slope gradient: 0 to 60 percent
Parent material: Mazama volcanic ash mixed with loess and colluvium
Lithology: basalt
Elevation: 3,800 to 4,400 feet
Climate: cold, wet winters and cool, dry summers
Mean annual precipitation: 15 to 23 inches
Mean annual air temperature: 42 to 44 degrees F
Frost-free period: 45 to 100 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Fivebit: on plateaus and backslopes, shallow soil in loamy-skeletal colluvium under scattered ponderosa pine, Douglas-fir or western juniper with sagebrush and Idaho fescue;
Bocker: on shoulders and plateau summits; very shallow soil without an argillic horizon; minor ash influence under sagebrush, Idaho fescue or bluebunch wheatgrass
Parsnip: on ridgetops and plateaus; shallow soil with argillic horizon, loess and volcanic ash mixed with loamy colluvium under Idaho fescue and bluebunch wheatgrass
DRAINAGE AND PERMEABILITY:
Drainage: well drained
Permeability: moderately rapid in surface and moderate in the argillic
USE AND VEGETATION:
Use: watershed, wildlife, recreation, livestock grazing
Potential native vegetation: western juniper, ponderosa pine, mountain big sagebrush, curl-leaf mountain mahogany, antelope bitterbrush, stiff sagebrush, Wyeth's creamy buckwheat, common yarrow, arrowleaf balsamroot, tapertip onion, wormleaf stonecrop, Cusick's peavine, Idaho fescue, Sandberg bluegrass, bluebunch wheatgrass, and western brome.
Plant associations: Dominant: CJG111 - JUOC/FEID-PSSPS (western juniper/Idaho fescue-bluebunch wheatgrass); may include: GB59 - FEID/PSSPS (Idaho fescue-bluebunch wheatgrass), CJS41 - JUOC/CELE/FEID-PSSPS (western juniper/curl-leaf mountain mahogany/Idaho fescue-bluebunch wheatgrass), and GB4121 - PSSPS-POSE (bluebunch wheatgrass-Sandberg bluegrass)
DISTRIBUTION AND EXTENT:
Distribution: MLRA 9; Palouse and Nez Perce Prairies of northeastern Oregon.
Extent: small
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES PROPOSED: Umatilla National Forest, Oregon 2008. Name is from a spring.
REMARKS: Diagnostic horizons and features recognized in this pedon (97-404) are:
mollic epipedon: 0 to 27 inches; A, ABt, Bt1 horizons
argillic horizon: 7 to 32 inches; ABt, Bt1, Bt2 horizons
vitrandic subgroup properties: 0 to 19 inches; A, ABt horizons
particle-size control section: 7 to 27 inches; ABt, Bt1 horizons
The Powellbutte Series has a distinct mixed volcanic ash surface (higher glass content) with a lithologic discontinuity between the mixed ash mantle and the underlying soil. The Tommycork Series lacks the distinct mixed volcanic ash surface (lower glass content) and consequently no lithologic discontinuity is recognized. Although both series have the same classification, the distinctness in the amount of ash is recognizable in the field. Additional review maybe needed for separation of Tommycork from Powellbutte series if they occur on the same landscape position with similar production and vegetative communities (interpretations). It maybe recommended to revise the Vitrandic subgroup criteria (increase the glass content criteria) if no interpretative value can be shown.