LOCATION HAFMAU                  OR

Tentative Series
IRD. JRD/DAL
02/2013

HAFMAU SERIES

The Hafmau series consists of shallow, moderately well drained soils on rolling mountain sideslopes and benches. They formed in mixed volcanic ash and colluvium over residuum from basalt or tuffs. Slopes are 5 to 40 percent. The mean annual precipitation is about 22 inches and mean annual temperature is about 42 degrees F.

TAXONOMIC CLASS: Clayey-skeletal, smectitic, frigid Lithic Ultic Argixerolls

TYPICAL PEDON: Hafmau stony ashy sandy loam, upland forest. (Colors are for dry soil unless otherwise noted.)

Oi--0 to 2 inches; slightly decomposed pine and fir litter

A1--2 to 4 inches; dark grayish brown (10YR 4/2) stony ashy sandy loam, very dark brown (10YR 2/2) moist; moderate medium platy structure; soft, friable, slightly sticky and slightly plastic; many very fine roots; many very fine and fine vesicular pores; 5 percent gravel, 5 percent cobbles and 5 percent stones; slightly acid (pH 6.2); abrupt smooth boundary. (2 to 4 inches thick)

A2--4 to 12 inches; dark brown (10YR 3/3) stony ashy sandy loam, very dark brown (10YR 2/2) moist; moderate fine and medium subangular blocky structure; soft, friable, slightly sticky and slightly plastic; many very fine, fine and medium roots, common coarse and very coarse roots; many very fine and fine continuous tubular pores; 5 percent gravel, 5 percent cobbles and 5 percent stones; slightly acid (pH 6.2); clear smooth boundary. (6 to 10 inches thick)

2Bt--12 to 19 inches; very dark brown (10YR 2/2) extremely cobbly clay, black (10YR 2/1) moist; strong fine and medium angular blocky structure; hard, firm, sticky and plastic; common medium roots; many very fine and fine continuous tubular pores; many moderately thick clay films on ped faces and lining pores; 15 percent gravels, 35 percent cobbles and 25 percent stones;; slightly acid (pH 6.4); clear wavy boundary. (6 to 8 inches thick)

2R--19 inches; basalt

TYPE LOCATION: Crook County, Oregon;
Section 3, T. 18 S., R. 18 E.
Latitude: 44 degrees 02 minutes 29 seconds, North
Longitude: 120 degrees 32 minutes 49 seconds, West
UTM coordinates: zone 10; north 4879179 meters, east 696543 meters; NAD 27
USGS Quadrangle: Eagle Rock SE

RANGE IN CHARACTERISTICS:
Soil Temperature: frigid regime
Mean Annual Soil Temperature: 40 to 45 degrees F
Mean Summer Soil Temperature: 47 to 53 degrees F
Mean Winter Soil Temperature: 32 to 36 degrees F
Soil Moisture: xeric regime, dry 45 to 60 consecutive days in late summer and early fall

Particle-size control section: argillic horizon
clay content (weighted average): 35 to 65 percent
rock fragment content (weighted average): 35 to 85 percent

Diagnostic horizons and features:
andic soil properties: upper boundary at the mineral surface; 7 to 13 inches thick
A1+1/2Fe (ammonium oxalate): 0.4 to 0.8 percent
P retention: 25 to 50 percent
0.02-2.0mm fraction: 60 to 80 percent of fine earth fraction
glass content in 0.02-2.0mm fraction: 15 to 45 percent
mollic epipedon: 7 to 19 inches thick
depth to argillic horizon: 7 to 13 inches
lithic contact, depth below mineral surface: 14 to 20 inches

A horizon:
color, moist:10YR 2/1, 2/2, 3/1, 3/2, 3/3
color, dry: 10YR 3/3, 4/2, 4/3, 5/2, 5/3
texture: ST-ASHY-SL, ST-ASHY-L, ST-ASHY-LS, ST-ASHY-FSL
clay content: 8 to 18 percent
rock fragment content: 15 to 30 percent
gravel: 5 to 10 percent
cobbles: 5 to 10 percent
stones: 5 to 10 percent
reaction: moderately acid to slightly acid; pH: 5.6 to 6.5
base saturation (sum of cations): 65 to 75 percent

2Bt horizon:
color, moist: 10YR 2/1, 2/2, 3/1, 3/2, 3/3
color, dry: 10YR 2/2, 3/1, 3/2, 3/3, 4/2, 4/3
texture: CBX-CL, CBX-C, STX-C
clay content: 35 to 65 percent
rock fragment content: 35 to 85 percent
gravel: 10 to 30 percent
cobbles: 10 to 55 percent
stones: 5 to 20 percent
reaction: moderately acid to slightly acid; pH: 5.6 to 6.5

COMPETING SERIES:
Polecreek soils - do not have organic (O) horizons on the surface and do not have vitrandic subgroup properties in mineral surface horizons.

GEOGRAPHIC SETTING: Hafmau soils are on rolling mountain sideslopes, benches and ridges. These soils formed in ash mixed in colluvium over residuum from basalt or rhyolitic tuffs. Slopes are 5 to 40 percent. Elevations range from 4,000 to 6,000 feet. The mean annual precipitation is 15 to 25 inches. The mean annual temperature is 40 to 45 degrees F., and the frost free season is 45 to 60 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Erakatak, Humarel (T), Maucav (T), Normauk (T), Hafling (T) and Shotsprings (T) series. Erakatak, Humarel (T), Maucav (T), and Shotspring soils are 20 to 40 inches deep. Meaufun (T) soils are 40 to 60 inches deep. Normauk (T) soils are 60 to 80 inches deep. Hafling (T) soils do not have an argillic horizon.

DRAINAGE AND PERMEABILITY: Moderately well drained; medium to rapid runoff; rapid permeability in the surface ash mantle and slow in the underlying clay.

USE AND VEGETATION: timber production, livestock grazing and wildlife habitat. Vegetation is primarily Douglas-fir, ponderosa pine, elk sedge and heartleaf arnica. Blue Mountain Plant Association: Douglas-fir/elk sedge - CDG1-11 (Hall, 1989, Plant Association and Management Guide for the Ochoco and Southern Blue Mountain Areas)

DISTRIBUTION AND EXTENT: Central Oregon, MLRA 10. These soils are of moderate extent.

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

SERIES PROPOSED: Crook County, Oregon. 2008

REMARKS: Diagnostic horizons and features in this pedon are:
mollic epipedon - from 2 to 19 inches. (A1, A2 and 2Bt horizons)
argillic horizon - from 12 to 19 inches. (2Bt horizon)
ultic subgroup feature - from 2 to 12 inches (A2 horizon)
vitrandic subgroup properties - from 2 to 12 inches (A1 and A2 horizons)
particle-size control section - from 12 to 19 inches (2Bt horizon)
lithic contact - at 19 inches (2R horizon)

ADDITIONAL DATA: National Soil Survey Laboratory; Pedon ID: 99OR023002

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National Cooperative Soil Survey
U.S.A.