LOCATION CUPOLA OREstablished Series
TAXONOMIC CLASS: Ashy-skeletal, amorphic, mesic Typic Udivitrands
TYPICAL PEDON: Cupola cobbly loam - forested. (Colors are for moist soil unless otherwise noted.)
A--0 to 2 inches; very dark brown (10YR 2/2) cobbly loam, dark grayish brown (10YR 4/2) dry; strong fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many fine roots; many fine irregular pores; 10 percent concretions; 20 percent cobbles; strongly acid (pH 5.4); abrupt smooth boundary. (2 to 4 inches thick)
A2--2 to 6 inches; dark brown (7.5YR 3/4) cobbly loam, brown (7.5YR 5/4) dry; moderate very fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many fine roots; many very fine irregular pores; 10 percent concretions and gravel, 20 percent cobbles; moderately acid (pH 6.0); gradual wavy boundary. (2 to 5 inches thick)
Bw1--6 to 18 inches; dark brown (7.5YR 4/4) very cobbly loam, light brown (7.5YR 6/4) dry; weak very fine and fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; common fine and medium roots; many fine and very fine irregular pores; 15 percent concretions and gravel; 25 percent cobbles; slightly acid (pH 6.1); gradual wavy boundary. (6 to 12 inches thick)
Bw2--18 to 32 inches; dark brown (7.5YR 4/4) very cobbly loam, light brown (7.5YR 6/4) dry; weak fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; common fine roots; many very fine irregular pores; common fine tubular pores; 25 percent gravel, 30 percent cobbles; slightly acid (pH 6.4); abrupt wavy boundary. (10 to 20 inches thick)
Cd--32 to 60 inches; variegated yellowish brown and brownish yellow (10YR 5/6, 6/6, 5/8) weakly consolidated very cobbly loam; massive; very hard, firm, slightly sticky and slightly plastic; 20 percent gravel, 30 percent cobbles; slightly acid (pH 6.2).
TYPE LOCATION: Lane County, Oregon; 2 miles east of Blue River, east of road going to Blue River Reservoir and on exposed bank of gravel pit on terrace saddle in southeast 1/4 southeast 1/4 of sec. 14, T. 16 S., R. 4 E.
RANGE IN CHARACTERISTICS: The soil is usually moist and is dry in all parts between depths of 8 to 24 inches for less than 45 consecutive days. The mean annual soil temperature is 48 to 52 degrees F. Thickness of the solum and depth to Cd horizon is 20 to 40 inches. Depth to bedrock is more than 60 inches. The particle-size control section averages more than 35 percent rock fragments. The soil reaction is slightly acid to strongly acid. The moist bulk density is 0.70 to 0.80 g/cc throughout the solum.
The A horizon has hue of 10YR or 7.5YR, value of 2 or 3 moist, 4 or 5 dry, and chroma of 2 to 4 moist and dry. It is 20 to 35 percent coarse fragments of which 5 to 15 percent are gravel and concretions and 15 to 25 percent are cobbles.
The B horizon has hue of 10YR or 7.5YR, value of 5 or 6 dry, 3 or 4 moist, and chroma of 3 or 4 moist and dry. It is very cobbly loam or very cobbly sandy loam with 5 to 18 percent clay. It has 15 to 25 percent gravel and concretions and 20 to 40 percent cobbles.
The C horizon is very cobbly loam, very cobbly sandy loam, or extremely cobbly loam. It has 15 to 25 percent gravel and 25 to 45 percent cobbles. It is weakly consolidated or moderately consolidated.
COMPETING SERIES: There are no other series in this family.
GEOGRAPHIC SETTING: Cupola soils are on terraces and mountain footslopes. Slopes are 3 to 30 percent. The soils formed in medium textured cobbly glacial outwash from mixed volcanic materials. Elevation is 1,000 to 2,500 feet. The climate is characterized by warm wet winters and hot dry summers. The mean annual precipitation is 65 to 85 inches. The mean annual temperature is 46 to 50 degrees F. The mean January temperature is 34 degrees F, and the mean July temperature is 63 degrees F. The frost-free period is 120 to 160 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Saturn, Jimbo, and Haflinger soils. Saturn soils are fine-loamy over fragmental. Jimbo soils are nearly free of rock fragments in the control section and are influenced by pyroclastic materials. Haflinger soils are sandy-skeletal.
DRAINAGE AND PERMEABILITY: Well-drained; moderately rapid permeability in the solum and moderately slow permeablility in the substratum.
USE AND VEGETATION: This soil is used mainly for timber production, recreation, and homesites. The native vegetation is mainly Douglas fir, western hemlock, incense cedar, red alder, salal, beargrass, swordfern, and brackenfern.
DISTRIBUTION AND EXTENT: Terraces and footslopes of the Cascade Mountains in western Oregon; MLRA 3. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Lane County Area, Oregon, 1981.
REMARKS: This draft represents a change in classification from medial-skeletal, mesic Entic Dystrandepts to ashy-skeletal, mesic Typic Udivitrands based on the Andisol Order.
Diagnostic horizons and features recognized in this pedon include:
ochric epipedon
cambic horizon - from 6 to 32 inches (Bw1 and Bw2 horizons).
andic properties - from surface to 60 inches (A1, A2, Bw1, Bw2, and Cd horizons).
particle-size control section - from surface to 40 inches (A1, A2, Bw1, Bw2, and upper Cd horizon) with 46 percent rock fragments (calculated).
1500 kPa water retention is 7.8 to 9.8 percent (air dry) and 21.5 to 29.2 percent (undried) from surface to 32 inches.
ADDITIONAL DATA: Characterization data from one pedon (S705R-39-14(1-5)) from SCS Lincoln Laboratory.