LOCATION KUSU OREstablished Series
TAXONOMIC CLASS: Ashy-skeletal, glassy, frigid Typic Vitrixerands
TYPICAL PEDON: Kusu very gravelly loam - on a 30 percent northeast facing slope, woodland. (Colors are for moist soil unless otherwise noted.)
Oi-- 2 inches to 0; organic layer of needles and twigs
A-- 0 to 4 inches; very dark grayish brown (10YR 3/2) very gravelly loam, grayish brown (10YR 5/2) dry; weak fine granular structure; soft, friable, nonsticky and nonplastic; many very fine and fine roots; many very fine and fine irregular pores; 35 percent gravel; neutral (pH 6.6); clear smooth boundary. (4 to 8 inches thick)
AB-- 4 to 14 inches; dark yellowish brown (10YR 3/4) very gravelly loam, brown (10YR 5/3) dry; weak fine subangular blocky structure; soft, friable, nonsticky and nonplastic; many very fine and fine roots; many very fine and fine tubular pores; 35 percent gravel; neutral (pH 6.6); clear smooth boundary. (0 to 12 inches thick)
Bw1-- 14 to 22 inches; dark brown (10YR 4/3) very gravelly sandy loam, pale brown (10YR 6/3) dry; moderate fine subangular blocky structure; soft, friable, slightly sticky and slightly plastic; many very fine, fine and common medium roots; many very fine, fine and common medium tubular pores; 35 percent gravel; slightly acid (pH 6.4); clear smooth boundary.
Bw2-- 22 to 32 inches; dark brown (10YR 4/3) extremely gravelly loam, pale brown (10YR 6/3) dry; moderate fine and medium subangular blocky structure; soft, friable, slightly sticky and slightly plastic; many very fine, fine and common medium roots; many very fine, fine and common medium tubular pores; 65 percent gravel; slightly acid (pH 6.4); gradual smooth boundary.
Bw3-- 32 to 51 inches; brown (10YR 4/3) extremely gravelly loam, light pale brown (10YR 6/4) dry; moderate fine and medium subangular blocky structure; soft, friable, slightly sticky and slightly plastic; common very fine and fine roots; common very fine and fine tubular pores; 20 percent cobbles and 65 percent gravel; slightly acid (pH 6.2); clear wavy boundary. (Combined thickness of the Bw horizon is 34 to 44 inches)
R-- 51 inches; fractured tuff
TYPE LOCATION: Wasco County, Oregon; 1000 feet east and 3000 feet north of the SW corner of section 30 T.7 S., R.13 E. (Warm Springs Indian Reservation); Latitude 44 degrees, 56 minutes, 0 seconds N; Longitude 121 degrees, 13 minutes, 52 seconds W.
RANGE OF CHARACTERISTICS: These soils are usually moist but are dry in all parts of the moisture control section for 45 to 60 consecutive days within the four months following the summer solstice. The mean annual soil temperature is 43 to 46 degrees F. The moist bulk density is 0.80 to 0.90 g/cc. Depth to bedrock is 40 and 60 inches. Phosphate retention is 25 to 35 percent and acid oxalate aluminum plus 1/2 iron is between 0.4 and 1.0 percent in the less than 2.0 mm fraction. There is 50 to 65 percent volcanic glass and glass aggregate in the 0.02 to 2.0 mm fraction. The 15-bar water is 8 to 12 percent on air dried samples. The particle-size control section has a field estimated clay of 15 to 25 percent. It is neutral to moderately acid.
The A and AB horizon have value of 2 or 3 moist, 4 or 5 dry and chroma of 2 through 4 moist and dry. It is very gravelly loam or very gravelly sandy loam and contains 35 to 50 percent gravel.
The Bw horizon has value of 3 or 4 moist, 6 or 7 dry and chroma of 3 or 4 moist and dry. It is loam or sandy loam and contains 0 to 20 percent cobbles and 35 to 65 percent gravel.
COMPETING SERIES: These are the Doe, Grenet, Pettijohn, Stices, Twelvemile, and Yallani soils. Doe and Pettijohn soils are very deep. Grenet soils have 10 to 18 percent clay in the control section and are moderately deep to a paralithic contact. Stices soils are very deep to bedrock. Twelvemile soils are very deep, dry for more than 60 consecutive days after the summer solstice, and have 7 to 18 percent clay (apparent field estimate) in the particle-size control section. Yallani soils are very deep to bedrock and dry for 60 to 90 consecutive days.
GEOGRAPHIC SETTING: Kusu soils are on gently sloping to steep north-facing slopes and ridgetops of mountains. Elevations range from 2800 to 4600 feet. Slopes are 0 to 65 percent. The soil formed in colluvium and residuum derived dominantly from tuff with an influence of volcanic ash. The climate is characterized by cold and wet winters and hot and dry summers. The mean annual precipitation is 20 to 40 inches. The mean annual temperature is 41 to 44 degrees F. The frost-free period is 60 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Mutton, Peahke, and competing Grenet soils. Mutton soils are on adjacent north-facing side slopes at lower elevations and are very deep to bedrock. Peahke soils are loamy-skeletal, moderately deep to bedrock and are on adjacent south-facing side slopes.
DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderately rapid.
USE AND VEGETATION: These soils are used for timber production, livestock grazing, watershed and wildlife habitat. The native vegetation is Douglas fir, ponderosa pine and grand fir with an understory of snowbrush ceanothus, greenleaf manzanita, Idaho fescue, western fescue, common snowberry, golden chinkapin, and tailcup lupine.
DISTRIBUTION AND EXTENT: North-central Oregon; MLRA 6. The soils are of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Wasco County (Warm Springs Indian Reservation), Oregon, 1993.
REMARKS: Diagnostic horizons and features in this pedon are:
Ochric epipedon
Cambic horizon - the zone from 14 to 51 inches (Bw1, Bw2, Bw3 horizons).
Andic properties - from the surface to 51 inches (A, AB, Bw1, Bw2, Bw3 horizons)
Particle-size control section - from the surface to 40 inches.
Ashy-skeletal family - more than 30 percent volcanic glass and glass aggregate and 52 percent rock fragments (calculated).
Phosphate retention, acid oxalate aluminum and iron, volcanic glass, and 15-bar water retention is based on laboratory data from similar soils.