LOCATION HOFFER OR

Established Series
IRD. RJO/DAL/KMS
01/2019

HOFFER SERIES

Landscape--mountains
Landform--mountain slopes
Slope--15 to 60 percent
Parent material--thick mantle of volcanic ash over colluvium and residuum derived from granite
Mean annual precipitation--about 910 mm
Mean annual air temperature--about 4 degrees C
Depth class--deep or very deep to paralithic contact
Drainage class--well drained
Soil moisture regime--udic
Soil temperature regime--cryic
Soil moisture subclass--typic

TAXONOMIC CLASS: Ashy over loamy, amorphic over isotic Typic Vitricryands

TYPICAL PEDON: Hoffer ashy silt loam in an area of woodland, on a 9-percent, southwest-facing slope at an elevation of 2042 m

Oi--0 to 3 cm; needles and twigs

A--3 to 18 cm; ashy silt loam, yellowish brown (10YR 5/4) dry, dark yellowish brown (10YR 3/4) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many fine and very fine and common medium roots; many very fine and common fine irregular pores; slightly acid (pH 6.5); clear smooth boundary

Bw1--18 to 43 cm; ashy silt loam, light yellowish brown (10YR 6/4) dry, dark yellowish brown (10YR 3/4) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common fine, medium, and coarse roots; many very fine and few fine tubular pores; slightly acid (pH 6.5); clear smooth boundary

2Eb--43 to 76 cm; sandy loam, light yellowish brown (10YR 6/4) dry, dark yellowish brown (10YR 4/4) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; few fine and medium roots; many very fine and fine tubular pores; 5 percent gravel; moderately acid (pH 6.0); gradual smooth boundary

2Bwb--76 to 119 cm; sandy loam, yellow (10YR 7/6) dry, yellowish brown (10YR 5/6) moist; massive; soft, friable, nonsticky and nonplastic; few fine roots; many very fine tubular pores; 5 percent gravel; moderately acid (pH 6.0); clear smooth boundary

2Cr--119 to 157 cm; grus (weathered granite) that crushes to loamy sand, yellow (10YR 8/6) dry, yellowish brown (10YR 5/6) moist; single grain; loose, nonsticky and nonplastic; 5 percent gravel; slightly acid (pH 6.5)

2R--157 cm; hard granite

TYPE LOCATION: Baker County, Oregon, about 535 m west and 280 m south of the northeast corner of section 35, T. 8 S., R. 36 E.; latitude 44.8287147, longitude -118.2624638, datum WGS 84 (coordinates and PLSS details estimated from a point on a hard copy map)

RANGE IN CHARACTERISTICS:
Mean annual soil temperature--2 to 5 degrees C
Mean summer soil temperature--6 to 8 degrees C
Mean winter soil temperature--0 to 2 degrees C
Soil moisture--dry 30 to 45 days in summer
Depth to paralithic contact--100 to 200 cm
Thickness of ash-influenced layers--40 to 80 cm

Estimated properties of layers influenced by volcanic ash
*Ammonium oxalate extractable Al + 1/2 Fe--1.5 to 3.0 percent
*0.02- to 2.0-mm fraction--40 to 60 percent
*Glass content in 0.02- to 2.0-mm fraction--60 to 90 percent
*1/3-bar bulk density--0.65 to 1.00 g/cm3
*Phosphate retention--60 to 90 percent
*15-bar water retention--5 to 12 percent (dried samples)
*8 x Si plus 2 x Fe--5 to 12 percent

Particle-size control section
*Ashy upper part--40 to 80 cm thick; 3 to 6 percent clay; 0 to 10 percent rock fragments
*Loamy lower part--25 to 60 cm thick; 2 to 8 percent clay; 0 to 20 percent rock fragments
*Rock fragment shape--subrounded

A horizon
Moist color--10YR 3/4
Dry color--10YR 5/4, 10YR 6/3, 10YR 6/4
Fine-earth texture--ashy silt loam
Clay content--3 to 6 percent
Sand content--30 to 40 percent
Organic matter content--2 to 4 percent
Total rock fragment content--0 to 5 percent
Gravel content--0 to 5 percent
Reaction--6.1 to 6.5
Base saturation (sum of bases)--5 to 25 percent
Thickness--8 to 20 cm

Bw horizon
Moist color--10YR 3/4, 10YR 4/3, 10YR 4/4
Dry color--10YR 6/4, 10YR 7/3, 10YR 7/4, 10YR 8/4
Fine-earth texture--ashy silt loam
Clay content--3 to 8 percent
Sand content--30 to 45 percent
Organic matter content--1.0 to 2.5 percent
Total rock fragment content--0 to 10 percent
Gravel content--0 to 5 percent
Cobble content--0 to 5 percent
Reaction--6.1 to 6.5
Base saturation (sum of bases)--2 to 10 percent
Thickness--25 to 70 cm

2Eb horizon, and 2Ab horizon (where present)
Moist color--10YR 4/4, 10YR 5/3, 10YR 5/4
Dry color--10YR 6/4, 10YR 7/3, 10YR 7/4, 10YR 8/2
Fine-earth texture--coarse sandy loam, sandy loam
Clay content--2 to 8 percent
Sand content--50 to 70 percent
Organic matter content--1 to 2 percent
Total rock fragment content--0 to 15 percent
Gravel content--0 to 10 percent
Cobble content--0 to 5 percent
Reaction--5.6 to 6.5
Base saturation (sum of bases)--40 to 60 percent
Thickness--10 to 35 cm

2Bwb horizon, and 2C horizon (where present)
Moist color--10YR 5/3, 10YR 5/6, 10YR 6/6, 2.5Y 5/2, 2.5Y 5/3
Dry color--10YR 7/3, 10YR 7/6, 10YR 8/3, 2.5Y 7/4, 2.5Y 8/3
Fine-earth texture--loamy sand, very fine sandy loam, sandy loam
Clay content--0 to 8 percent
Sand content--50 to 75 percent
Organic matter content--0.5 to 2.0 percent
Total rock fragment content--0 to 20 percent
Gravel content--0 to 20 percent
Reaction--5.6 to 6.5
Base saturation (sum of bases)--40 to 60 percent
Thickness--25 to 70 cm

COMPETING SERIES:
Digit--very deep (150 cm or more) to lithic contact (basalt); ashy silt loam that has 0 to 20 percent gravel; 1.5 to 3.0 percent ammonium oxalate extractable Al plus 1/2 Fe, 60 to 90 percent glass, and 60 to 90 percent phosphorus retention in ashy part of particle-size control section; loamy part of particle-size control section averages 10 to 24 percent clay and 0 to 32 percent gravel; formed in volcanic ash over alluvium derived from basalt
Spukwush--very deep (150 cm or more) to paralithic contact (tuff); ashy loamy sand mantle that is 5 to 30 percent pumice and cinders; spodic Bs horizon; glassy family mineralogy; lower part of particle-size control section averages 18 to 27 percent clay; formed in ash, pumice, and cinders over weathered tuffaceous material
Tusip--deep (100 to 150 cm) to paralithic contact (sandstone); ashy sandy loam or ashy loamy sand; 5 to 10 percent hard cinders in ashy part of particle-size control section; spodic Bs horizon; glassy family mineralogy; gravelly sandy loam or gravelly fine sandy loam and average of 10 to 18 percent clay and 15 to 30 percent gravel in loamy part of particle-size control section; formed in ash, pumice, and cinders over colluvium and residuum derived from sandstone

GEOGRAPHIC SETTING:
Elevation--1790 to 2150 m
Climate--cold, wet winters; cool, moist summers
Mean annual precipitation--700 to 1180 mm
Mean annual air temperature--3 to 5 degrees C
Frost-free period--40 to 75 days

GEOGRAPHICALLY ASSOCIATED SOILS:
Prouty--in steeper, more convex positions; 50 to 100 cm (moderately deep) to lithic contact; ash mantle less than 35 cm thick
Windicreek (T)--on steeper slopes; ashy over loamy-skeletal

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Saturation during normal years--none
Flooding--none
Ponding--none
Saturated hydraulic conductivity (Ksat)--moderately high over high

USE AND VEGETATION:
Use--watershed, wildlife habitat, timber production, recreation
Native vegetation--subalpine fir, Engelmann spruce, lodgepole pine, grand fir, grouse huckleberry, heartleaf arnica, sidebells wintergreen, darkwoods violet, Utah honeysuckle, sweetcicely, lupine, prince's pine, sickletop lousewort, skunkleaf polemonium, western meadow-rue, Sitka valerian, northwestern sedge, pinemat manzanita
Plant association--PICO(ABLA)VASC/POPU3; may include ABLA/VASC/POPU3 or ABLA/POPU3

DISTRIBUTION AND EXTENT: Blue Mountains of northeastern Oregon; MLRA 43C; small extent

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Portland, Oregon

SERIES PROPOSED: Wallowa-Whitman National Forest, Oregon; 2018

REMARKS:
Diagnostic horizons and other features recognized in this pedon
*Ochric epipedon
*Cambic horizon--zone from 18 to 43 cm
*Volcanic glass--zone from 3 to 43 cm
*Andic soil properties--zone from 3 to 43 cm
*Particle-size control section--ashy part includes zone from 3 to 43 cm; loamy part includes zone from 43 to 104 cm

The Hoffer soils were not correlated as Vassar soils because of differences in the potential natural vegetation and characteristics of the ash mantle. The Hoffer series is mapped in northeast Oregon in areas that support subalpine fir plant associations, which are indicative of a cryic soil temperature regime. The Vassar series is mapped in northeast Washington and northern Idaho in areas that support Douglas-fir, grand fir, ponderosa pine, western redcedar, and western larch, which are indicative of a frigid soil temperature regime (although the soils are classified as cryic). The frigid soil temperature regime appears to be correct for Vassar soils. The ash mantle of the soils in northeast Oregon have a higher content of glass and a higher percentage of ammonium oxalate Al plus 1/2 Fe than do the soils in northeast Washington and northern Idaho.

The ash in areas of Vassar soils mapped as cryic (if they exist) needs additional characterization before considering correlation to the Hoffer series.

National Cooperative Soil Survey
U.S.A.