LOCATION PIONEERGULCH            OR

Tentative Series
IRD.DCR/MPR
02/2025

PIONEERGULCH SERIES

Landscape--Mazama High Cascade mountains, southwestern Middle Cascade glaciated mountains
Landform--lateral moraines, colluvial aprons
Slope--8 to 55 percent
Parent material--colluvium and till derived from basalt and andesite mixed with pumice and volcanic ash
Mean annual precipitation--about 1450 mm
Mean annual air temperature--about 6 degrees C
Depth class--very deep
Drainage class--well drained
Soil moisture regime--udic
Soil temperature regime--frigid
Soil moisture subclass--typic

TAXONOMIC CLASS: Medial, amorphic, frigid Humic Udivitrands

TYPICAL PEDON: Pioneergulch paragravelly medial sandy loam, on a south-facing lateral moraine with a slope of 55 percent and an elevation of 1494 m

Oi--0 to 2 cm; slightly decomposed plant material; abrupt wavy boundary

A--2 to 13 cm; paragravelly medial sandy loam, brown (10YR 5/3) dry, very dark brown (10YR 2/2) moist; weak fine subangular blocky structure; soft, very friable, nonsticky, nonplastic; many very fine and common fine and medium roots; common very fine and fine dendritic tubular pores; 5 percent gravel and 15 percent pumice paragravel; moderately acid (pH 5.8); clear wavy boundary

AB--13 to 32 cm; gravelly medial sandy loam, brown (10YR 5/3) dry, dark brown (10YR 3/3) moist; weak fine subangular blocky structure; soft, very friable, nonsticky, nonplastic; many very fine and few fine and common medium roots; common very fine and fine dendritic tubular pores; 15 percent gravel, 3 percent cobbles, and 30 percent pumice paragravel; moderately acid (pH 5.9); clear wavy boundary

Bw--32 to 74 cm; gravelly medial sandy loam, pale brown (10YR 6/3) dry, dark brown (10YR 3/3) moist; weak fine subangular blocky structure; soft, very friable, nonsticky, nonplastic; common very fine and medium and few fine roots; common very fine dendritic tubular pores; 15 percent gravel, 5 percent cobbles, and 20 percent pumice paragravel; slightly acid (pH 6.2); clear wavy boundary

C--74 to 150 cm; cobbly medial loamy sand, pale brown (10YR 6/3) dry, dark brown (10YR 3/3) moist; single grain; loose, nonsticky, nonplastic; common very fine and medium and few fine roots; many very fine interstitial pores; 15 percent gravel, 10 percent cobbles, and 2 percent stones; slightly acid (pH 6.3)

TYPE LOCATION: Lane County, Oregon, about 4 km southwest of Diamond Peak in Willamette National Forest; 640 m north and 390 m east of the southwest corner of section 14, T. 24 S., R. 5 E., Willamette Meridian; latitude 43.48980, longitude -122.18600, datum WGS 84 (coordinates determined with a GPS)

RANGE IN CHARACTERISTICS:
Mean annual soil temperature--6 to 8 degrees C
Umbric epipedon--25 to 50 cm thick
Thickness of andic soil properties--all mineral horizons to a depth of 150 cm or more
Depth to base of cambic horizon--70 to 125 cm

Particle-size control section (weighted average)
*Clay content--2 to 10 percent
*Fine-earth fraction--less than 50 percent medium through very coarse sand
*Volcanic glass content in 0.02 to 2.0 mm fraction--30 to 90 percent
*Ammonium oxalate Al plus 1/2 Fe--2.0 to 4.0 percent
*1500 kPa water (air-dried samples)--12 to 15 percent
*1500 kPa water (undried)--less than 30 percent
*Phosphate retention--50 to 100 percent
*Total fragment content--less than 35 percent
*Pumice content--5 to 25 percent

O horizon
*Composition-slightly to moderately decomposed plant material
*Thickness--0 to 8 cm

A and AB horizons
*Value--2 or 3 moist, 4 or 5 dry
*Chroma--2 or 3 moist and dry
*Sand content--50 to 70 percent
*Total fragment content--5 to 50 percent
*Gravel content--0 to 35 percent
*Cobble content--0 to 5 percent
*Pumice paragravel content--5 to 35 percent
*Organic carbon content--2.0 to 4.0 percent
*Thickness--25 to 50 cm

Bw horizon
*Hue--10YR or 7.5YR
*Value--3 to 5 moist, 5 or 6 dry
*Chroma--3 or 4 moist or dry
*Sand content--50 to 70 percent
*Total fragment content--15 to 50 percent
*Gravel content--5 to 35 percent
*Cobble content--0 to 10 percent
*Stone content--0 to 5 percent
*Pumice paragravel content--5 to 25 percent
*Organic carbon content--1.0 to 3.0 percent
*Reaction--pH 5.6 to 6.5
*Thickness--20 to 90 cm

C horizon
*Value--3 to 5 moist, 6 or 7 dry
*Chroma--3 or 4 moist or dry
*Fine-earth texture--medial loamy sand, ashy sand
*Clay content--0 to 5 percent
*Sand content--70 to 90 percent
*Total fragment content--15 to 50 percent
*Gravel content--5 to 35 percent
*Cobble content--5 to 20 percent
*Stone content--0 to 5 percent
*Pumice paragravel content--0 to 5 percent
*Organic carbon content--less than 2.0 percent
*1500 kPa water (air-dried samples)--5 to 15 percent
*Phosphate retention--25 to 85 percent
*Ammonium oxalate Al plus Fe--0.4 to 2.0 percent
*Reaction--pH 5.6 to 6.5

COMPETING SERIES:
Potatohill--particle-size control section averages less than 5 percent pumice paragravel; high saturated hydraulic conductivity throughout profile

GEOGRAPHIC SETTING:
Elevation--1050 to 1525 m
Climate--warm, dry summers; cold, wet winters
Mean annual precipitation--1200 to 1800 mm
Mean annual air temperature--5 to 7 degrees C
Frost-free period--75 to 135 days

GEOGRAPHICALLY ASSOCIATED SOILS:
Chucksney--cryic soil temperature regime, greater than 15 percent 1500 kPa water (air-dried samples), located on south-facing glacial-valley walls
Lostwagon--cryic soil temperature regime, located on glacial-valley floors, moraines, glacial-valley walls, and cirque headwalls
Wilchutes--100 to 150 cm to lithic contact; located on ice-scoured mountains and volcanic cones
Waldor--50 to 75 cm to redox concentrations; located on glaciated mountains

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--well drained
Flooding--none
Ponding--none
Saturated hydraulic conductivity (Ksat)--high (very high in the lower part)

USE AND VEGETATION:
Use--recreation, wildlife habitat, timber production
Potential natural vegetation--Douglas-fir, grand fir, western hemlock, Shasta red fir, pipsissewa, Cascade barberry, sweet after death; commonly supports a grand fir/prince's pine (CWF211) plant association (see Field Guide to the Forested Plant Associations of the Westside Central Cascades of Northwest Oregon)

DISTRIBUTION AND EXTENT: Southwestern Cascade and High Cascade Mountains, Oregon; MLRA 3; small extent

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana

SERIES PROPOSED: Willamette National Forest, Lane County, Oregon; 2022; name from Pioneer Gulch marked on Emigrant Butte USGS 7.5-minute quadrangle

REMARKS:
Diagnostic horizons and other features in this pedon
*Particle-size control section--zone from 2 to 102 cm
*Umbric epipedon--2 to 32 cm
*Cambic horizon--32 to 74 cm
*Andic soil properties--zone from 2 to 150 cm
*Volcanic glass--zone from 2 to 150 cm

*Typical pedon ID--2021OR039767

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National Cooperative Soil Survey
U.S.A.