LOCATION WITKNEE                 OR

Tentative Series
IRD. JLW/RJO/DAL
03/2013

WITKNEE SERIES

The Witknee series consists of very deep, somewhat poorly drained soils on alluvial terraces of mountain valleys. Witknee soils formed in floodplain sediments from mixed lithology, dominated by volcanic rocks. Slopes are 0 to 5 percent. The mean annual precipitation is about 23 inches and the mean annual temperature about 42 degrees F.

TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, frigid Aquic Hapludolls

TYPICAL PEDON: Witknee very fine sandy loam, wet meadow, on 2 percent slope at elevation of 4,320 feet. (Colors are for moist soil unless otherwise noted.)

A1--0 to 5 inches; very dark grayish brown (10YR 3/2) very fine sandy loam, brown (10YR 5/3) dry; moderate fine and medium granular structure; hard, friable, nonsticky and slightly plastic; many fine, very fine and medium roots; many fine and very fine irregular pores; moderately acid (pH 6.0); clear smooth boundary.

A2--5 to 13 inches; very dark grayish brown (10YR 3/2) very fine sandy loam, brown (10YR 5/3) dry; moderate fine and medium subangular blocky structure; hard, friable, nonsticky and slightly plastic; many fine and very fine roots; many fine and very fine tubular pores; moderately acid (pH 6.0); clear smooth boundary. (Thickness of A horizons combined is 10 to 20 inches.)

Bw--13 to 25 inches; very dark gray (10YR 3/1) silt loam, light brownish gray (10YR 6/2) dry; common medium distinct reddish brown (5YR 4/3) redox concentrations; moderate medium prismatic structure parting to moderate fine and medium subangular blocky; very hard, firm, moderately sticky and moderate plastic; common fine and medium roots; common fine and medium tubular pores; slightly acid (pH 6.2); clear wavy boundary. (8 to 19 inches thick)

Bg--25 to 33 inches; dark grayish brown (10YR 4/2) sandy loam, light brownish gray (10YR 6/2) dry; many medium distinct reddish brown (5YR 4/3) redox concentrations; massive; hard, friable, nonsticky and nonplastic; common fine roots; common fine and medium tubular pores; 5 percent gravel; slightly acid (pH 6.4); abrupt wavy boundary. (8 to 32 inches thick)

2C--33 to 61 inches; brown (10YR 4/3) very gravelly loamy sand, yellowish brown (10YR 5/4) dry; massive; slightly hard, loose, nonsticky and nonplastic; 35 percent gravel, 15 percent cobbles, and 5 percent stones; slightly acid (pH 6.4).

TYPE LOCATION: Union County, Oregon
Section 20 (SW 1/4, NE 1/4, NW 1/4), T. 5 S., R. 35 E.
Latitude: 45 degrees, 7 minutes, 11 seconds
Longitude: 118 degrees, 27 minutes, 23 seconds
UTM Coordinates: Zone 11; Northing: 4997064.6; Easting: 385450.2
USGS Quadrangle: Fly Valley

RANGE IN CHARACTERISTICS:
Soil Temperature: frigid regime
Mean Annual Soil Temperature: 42 to 45 degrees F
Mean Summer Soil Temperature: 50 to 54 degrees F
Mean Winter Soil Temperature: 34 to 37 degrees F
Soil Moisture: udic regime; dry 25 to 45 days in summer

Particle-size Control Section: from 10 to 40 inches
Clay content, weighted average: 14 to 18 percent
Rock fragment content, weighted average: 0 to 25 percent

Diagnostic Horizons and Features:
mollic epipedon: 10 to 20 inches thick
depth to aquic conditions: 20 to 30 inches

Major Horizons:
A horizons: may include AC horizon:
color, moist: 10YR 3/1, 3/2
color, dry: 10YR 4/2, 5/3, 5/4
texture: SIL, VFSL, L
clay content: 15 to 18 percent
reaction: moderately acid to neutral; 5.6 to 7.3 pH

Bw horizon:
color, moist: 10YR 3/1, 4/2
color, dry: 10YR 6/2, 7/3
texture: SIL, FSL, SL
clay content: 12 to 18 percent
reaction: slightly acid to slightly alkaline; 6.1 to 7.8 pH

Bg horizon:
color, moist: 10YR 4/2, 4/4
color, dry: 10YR 6/2, 6/6, 7/2
texture: SL, GR-SL
clay content: 12 to 18 percent
rock fragment content: 0 to 35 percent
gravel: 0 to 35 percent
reaction: slightly acid to slightly alkaline; 6.1 to 7.8 pH

2C horizon:
color, moist: 10YR 3/2, 4/3
color, dry: 10YR 5/4, 6/2
texture: GRV-LS, GRV-SL
clay content: 5 to 15 percent
rock fragment content: 35 to 60 percent
gravel: 25 to 45 percent
cobbles: 0 to 20 percent
stones: 0 to 5 percent
reaction: slightly acid; 6.1 to 6.5 pH

COMPETING SERIES: These are the Sundell and Tolna series.
Sundell: moderately deep to limestone lithic contact; Bw horizon with free carbonates; formed in glacial material derived from limestone
Tolna: has Bw horizons with 18 to 24 percent clay; has 2C horizons with 2.5Y or 5Y hue, stratified sand, or loamy sand; formed in loamy outwash materials overlying stratified sand and gravel with more than 20 percent shale; upper part of particle-size control section is 18 to 24 percent clay

GEOGRAPHIC SETTING:
Landform: alluvial terraces on mountain valley floors
Slope gradient: 0 to 5 percent
Parent material: alluvial sediments
Lithology: mixed, dominated by volcanic rocks
Elevation: 4,000 to 5,000 feet
Climate: characterized by cold, wet winters and warm, dry summers
Mean annual precipitation: 20 to 25 inches
Mean annual air temperature: 40 to 43 degrees F.
Frost-free period: 40 to 80 days

GEOGRAPHICALLY ASSOCIATED SOILS:
Tovame (T): on intermediate terraces above influence of stream-channel ground water

DRAINAGE AND PERMEABILITY:
Drainage: somewhat poorly drained
Permeability: moderate over rapid

USE AND VEGETATION:
Use: watershed, wildlife habitat, livestock grazing and recreation
Native vegetation: moist meadows and includes cinquefoils, asters, pussytoes, sedges and baltic rush.
Ecological Site: Dominant: undetermined sedge community

DISTRIBUTION AND EXTENT:
Distribution: Blue Mountains of northeastern Oregon
Extent: small

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon

SERIES PROPOSED: Union County, Oregon 2007. The name is coined.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
mollic epipedon: 0 to 13 inches; A1, A2
cambic horizon: 13 to 25 inches: Bw
particle-size control section: 10 to 40 inches; A2, Bw, Bg, C
aquic conditions: 25 to 33 inches; Bg

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National Cooperative Soil Survey
U.S.A.