LOCATION DOWNARDS OR
Established Series
Rev. SCW/RWL
03/2013
DOWNARDS SERIES
The Downards series consists of very deep and deep, well drained soils formed in volcanic ash and colluvium derived from basalt. They are on canyon back slopes of dissected plateaus, hills, and mountains. Slopes are 15 to 90 percent. The mean annual precipitation is about 25 inches, and the mean annual temperature is about 43 degrees F.
TAXONOMIC CLASS: Loamy-skeletal, isotic, frigid Andic Hapludolls
TYPICAL PEDON: Downards cobbly ashy loam - woodland, on a 65 percent northwest-facing slope at an elevation of 2,480 feet. (Colors are for moist soil unless otherwise noted. When described on May 14, 1996, the soil was moist throughout.)
Oi--0 to 1 inch; slightly decomposed needles, twigs, moss, and cones.
A--1 to 4 inches; very dark brown (10YR 2/2) cobbly ashy loam, dark grayish brown (10YR 4/2) dry, moderate fine granular structure; slightly hard, friable, nonsticky and n0nplastic; few fine and common very fine roots; common fine and many very fine irregular pores; 10 percent cobbles and 5 percent gravel; neutral (pH 6.7); clear smooth boundary. (3 to 6 inches thick)
BA--4 to 13 inches; very dark grayish brown (10YR 3/2) gravelly ashy loam, grayish brown (10YR 5/2) dry; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common fine and many very fine roots; common fine and many very fine tubular pores; 10 percent cobbles and 20 percent gravel; neutral (pH 6.8); clear wavy boundary. (4 to 12 inches thick)
Bw1--13 to 21 inches; dark brown (10YR 3/3) very cobbly clay loam; brown (10YR 5/3) dry; moderate medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic, few fine and common very fine roots; common fine and many very fine tubular pores; 15 percent cobbles and 25 percent gravel; neutral (pH 6.8); gradual wavy boundary. (8 to 18 inches thick)
Bw2--21 to 62 inches; dark brown (7.5YR 3/2) very cobbly clay loam, brown (7.5YR 5/2) dry; moderate medium and coarse subangular blocky structure; hard, firm, moderately sticky and moderately plastic; few fine and common very fine roots; few fine and common very fine tubular pores; 40 percent cobbles and 15 percent gravel; neutral (pH 6.7)
TYPE LOCATION: Wallowa County, Oregon; 0.2 miles east of Rondowa or 8 miles northwest of Minam; 1,800 feet east and 2,000 feet south of the northwest corner of section 23, T. 3 N., R. 40 E. (Latitude 45 degrees, 43 minutes, 36 seconds N. and Longitude 117 degrees, 46 minutes, 49 seconds W.)
RANGE IN CHARACTERISTICS: These soils are dry in the soil moisture control section for 30 to 45 days during the summer. The mean annual soil temperature is 44 to 47 degrees F. The upper 7 to 14 inches has acid-oxalate extractable aluminum plus one-half iron of 1.0 to 2.0 percent, volcanic glass content of 10 to 20 percent and moist bulk density of 0.85 to 1.00 g/cc. The mollic epipedon is 20 to 30 inches. Depth to bedrock is typically greater than 60 inches but ranges to 40 inches. The particle size control section averages 18 to 27 percent clay and 35 to 60 percent rock fragments.
The A horizon has value of 2 or 3 moist, 4 or 5 dry and chroma of 2 or 3 moist and dry. It is ashy loam with 15 to 25 percent clay and 10 to 20 percent cobbles and 5 to 15 percent gravel.
The BA horizon has chroma of 2 or 3 moist and dry. It is ashy loam or ashy clay loam with 18 to 27 percent clay and 10 to 20 percent cobbles and 5 to 20 percent gravel.
The Bw horizon has hue of 7.5YR or 10YR, value of 3 or 4 moist, 5 or 6 dry, and chroma of 2 or 3 moist and dry. It is loam or clay loam with 25 to 35 percent clay. The upper portion of this horizon has 10 to 25 percent cobbles and 25 to 35 percent gravel. The lower portion has 0 to 15 percent stones, 25 to 40 percent cobbles, and 15 to 30 percent gravel.
COMPETING SERIES: There are no competing soils.
GEOGRAPHIC SETTING: Downards soils are on canyon back slopes of deeply dissected plateaus, and on hills and mountains. These soils are deep on south-facing slopes and very deep on north-facing slopes. Elevation is 2,000 to 3,000 feet on north-facing side slopes and 3,000 to 4,000 feet on south-facing side slopes. Slopes are 15 to 90 percent. These soils formed in volcanic ash and colluvium derived from basalt. The climate is characterized by cool, wet winters and warm, moist summers. The mean annual precipitation is 20 to 35 inches. The mean annual temperature is 42 to 45 degrees F. The frost free period is 70 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Emily,
Gwin,
Kettenbach,
Klicker, and
Wolot soils. These soils are mesic. Emily soils are xeric and are situated on foot slopes of canyons. Gwin and Kettenbach soils are found on south slopes and have argillic horizons. Gwin soils are shallow to bedrock and Kettenbach and Klicker soils are moderately deep. Klicker soils are on south-facing side slopes above 3,000 feet. Wolot soils lack rock fragments, have an ochric epipedon, and are positioned on terraces.
DRAINAGE AND PERMEABILITY: Well drained; moderately slow permeability.
USE AND VEGETATION: These soils are used for timber production. A minor use is wildlife habitat. Native vegetation is grand fir, Douglas fir, scattered Ponderosa pine, snowberry, queenscup beadlily, and rocky mountain maple.
DISTRIBUTION AND EXTENT: Northeast Oregon; MLRA 9. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Wallowa County, Oregon; 1998.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - 1 to 21 inches (A, BA, and 2Bw1 horizons). The 2Bw2 horizon has mollic colors but lacks the required organic carbon.
Cambic horizon - 21 to 62 inches (2Bw2 horizon).
Particle size control section - from 11 to 41 inches (lower part of BA, 2Bw1, and upper part of 2Bw2 horizons)
Andic features - 1 to 13 inches (A and BA horizons)
USFS plant association - ABGR/AGCL
Classification revised 02/01 from Haploborolls to Hapludolls based on Soil Taxonomy 8th edition.
This series concept of frigid is below the elevation range convention of 2,800 feet for Wallowa County, Oregon although the plant community has been consistently correlated to udic and frigid soil moisture and temperature regimes in other parts of the Blue Mountains (Oregon and Idaho). The rainfall distribution in combination with ash influence are the primary factors reflective in the udic/frigid consideration.
National Cooperative Soil Survey
U.S.A.