LOCATION DOWNEYGULCH             OR

Established Series
Rev. RJO/DAL/RWL
03/2013

DOWNEYGULCH SERIES

The Downeygulch series consists of moderately deep well drained soils on stable summits and foot slopes of plateaus. Downeygulch soils formed in mixed ash, loess, and colluvium derived from basalt. Slopes are 0 to 30 percent. The mean annual precipitation is about 25 inches and the mean annual temperature is about 43 degrees F.

TAXONOMIC CLASS: Coarse-loamy, isotic, frigid Vitrandic Haploxerepts

TYPICAL PEDON: Downeygulch gravelly ashy silt loam - forested, on a 10 percent convex southwest-facing slope at an elevation of 5,280 feet. (Colors are for moist soil unless otherwise noted.)

Oi--0 to 1 inch; slightly decomposed needles, twigs and cones

A--1 to 4 inches; brown (7.5YR 4/2) gravelly ashy silt loam, brown (7.5YR 5/4) dry; weak fine subangular blocky structure parting to weak fine granular; soft, friable, slightly sticky and slightly plastic; many very fine and fine roots; common fine irregular pores; 20 percent gravel, slightly acid (pH 6.5); clear smooth boundary. (4 to 12 inches thick)

Bw1--4 to 14 inches; brown (7.5YR 4/4) gravelly ashy silt loam, brown (7.5YR 5/4) dry; moderate medium subangular blocky structure parting to moderate fine and very fine subangular blocky; soft, friable, slightly sticky and slightly plastic; few very fine and medium, and common fine roots; few fine tubular pores; 20 percent gravel; slightly acid; (pH 6.5) gradual smooth boundary

Bw2--14 to 25 inches; strong brown (7.5YR 4/6) gravelly ashy silt loam, strong brown (7.5YR 5/6) dry; weak very fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; few fine and medium roots; few fine irregular pores; 15 percent gravel and 5 percent cobbles; neutral (pH 7.2); abrupt irregular boundary. (Combined thickness of the Bw horizon is 16 to 28 inches)

2R--25 inches; basalt bedrock

TYPE LOCATION: Wallowa County, Oregon, 1580 feet south and 1580 feet west of the northeast corner of Section 21, T.3 S., R.47 E. (Latitude 45 degrees, 17 minutes, 26 seconds, N; Longitude 116 degrees, 56 minutes, 27 seconds W.)

RANGE IN CHARACTERISTICS: The soils are dry in all parts between 8 and 24 inches for 45 to 60 consecutive days during the summer. The mean annual soil temperature is 42 to 45 degrees F. Depth to bedrock is 20 to 40 inches. The particle-size control section has 12 to 18 percent clay and 5 to 30 percent rock fragments. Hue is 10YR, 7.5YR, or 5YR. Base saturation (ammonium acetate) is 60 to 85 percent.
The A horizon has value of 3 or 4 moist, 5 or 6 dry and chroma of 2 to 4 moist or dry. It is gravelly ashy silt loam with 15 to 25 percent gravel. It has 0.4 to 0.9 percent acid oxalate extractable aluminum plus one-half iron and 10 to 20 percent volcanic glass. Reaction is slightly to strongly acid.

The Bw horizon has value of 3 or 4 moist, 5 or 6 dry and chroma of 3 to 6 moist or dry. It is gravelly ashy silt loam, ashy silt loam, gravelly ashy loam, or ashy loam with 5 to 30 percent gravel and 0 to 10 percent cobbles. It has 0.4 to 0.9 percent acid oxalate extractable aluminum plus one-half iron and 5 to 10 percent volcanic glass. Reaction is neutral to strongly acid.

COMPETING SERIES:
Ardenmont -- deep to a paralithic contact (weathered schist); dry for 60 to 75 consecutive days
Cobbler -- very deep; formed in colluvium and residuum from metamorphic rocks with an admixture of volcanic ash and loess
Enson moderately deep to densic contact; dry for 60 to 75 consecutive days
Green Bluff -- very deep; lamellae and distinct clay films in E & Bt horizons; dry for 60 to 80 consecutive days
Labuck -- moderately deep to a paralithic contact (decomposed granodiorite); dry for 60 to 80 consecutive days
Micapeak -- moderately deep to a paralithic contact (weathered micaceous schist and gneiss); dry for 60 to 75 consecutive days
Quinnamose -- deep to a paralithic contact (weathered micaceous schist)
Stapaloop -- very deep; lamellae in lower part of particle-size control section; dry for 60 to 75 consecutive days

Similar soils with mixed mineralogy:
Leadpoint -- moderately deep to a paralithic contact; mixed mineralogy; dry for 45 to 60 consecutive days
Waits -- very deep and have free carbonates in the particle-size control section; mixed mineralogy; dry for 45 to 60 consecutive days.

GEOGRAPHIC SETTING: Downeygulch soils are on summits and foot slopes of plateaus. Elevations are 3,400 to 5,800 feet. Slopes are 0 to 30 percent. The soil formed in mixed ash, loess, and colluvium derived from basalt. Climate is characterized by cold, wet winters and hot, dry summers. Mean annual precipitation is 20 to 35 inches. Mean annual temperature is 41 to 45 degrees F. Frost-free period is 70 to 100 days.

GEOGRAPHICALLY ASSOCIATED SOILS:
Fivebeaver: on plateaus and backslopes; shallow; minor influence of volcanic ash in loamy-skeletal colluvium; under ponderosa pine, Douglas-fir, common snowberry and mallow ninebark
Kamela: on ridge crests and shoulder slopes; moderately deep to basalt with a mixed mantle of ash and loess over loamy-skeletal colluvium; under grand fir, Douglas-fir, rocky mountain maple, ninebark, heartleaf arnica and prince's pine.
Thirstygulch: on convex sideslopes and shoulders near rock outcrop; shallow to bedrock with minor amount of volcanic ash mixed with loess and colluvium from basalt; under ponderosa pine, Douglas-fir, common snowberry, and elk sedge
Lowerbluff: on plateaus; shallow to hard basalt; volcanic ash mixed with loess and colluvium; under grand fir, Douglas-fir, birchleaf spiraea and pinegrass

DRAINAGE AND PERMEABILITY: Well drained; permeability is moderate.

USE AND VEGETATION: These soils are used for watershed, recreation, timber production, and wildlife habitat. The native vegetation is ponderosa pine, Douglas-fir, grand fir, pinegrass, elk sedge, lupine, woodland strawberry, and big huckleberry.

DISTRIBUTION AND EXTENT: Northeast Oregon; MLRA 9. The soils are of moderate extent.

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

SERIES ESTABLISHED: Wallowa County Area, Oregon 1998. The source of the name is from a gulch.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from 1 to 4 inches (A horizon)
Cambic horizon - the zone from 4 to 25 inches (Bw1 and Bw2 horizons)
Vitrandic subgroup feature - the zone from 1 to 25 inches (A, Bw1, and Bw2 horizons) with 0.6, 0.6, 0.4 percent acid oxalate extractable aluminum plus one-half iron and 14, 10, and 6 percent volcanic glass, respectively
Particle-size control section - the zone from 11 to 25 inches having a weighted average of 17 percent clay and 16 percent rock fragments

Classification revised 04/2008 from mixed, superactive to isotic to concur with correlated classification of laboratory data pedon

ADDITIONAL DATA: Laboratory data available for this pedon. Reference sample #S92OR-063-013, for Wallowa County, Oregon, NSSL, Lincoln, NE., 1/94.

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National Cooperative Soil Survey
U.S.A.