LOCATION RUSTYBUTTE OREstablished Series
TAXONOMIC CLASS: Loamy-skeletal, magnesic, isomesic Typic Hapludolls
TYPICAL PEDON: Rustybutte gravelly clay loam - woodland, on a 55 percent north-facing slope at an elevation of 220 feet. (When described on April 11, 1991 the soil profile was moist throughout. Colors are for moist soil unless otherwise noted.)
Oi--1 inch to 0; partially decomposed needles, leaves, twigs and woody materials.
A---0 to 8 inches; very dark brown (10YR 2/2) gravelly clay loam, dark brown (10YR 3/3) dry; moderate very fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, many fine, and few medium and coarse roots; few fine tubular pores; 15 percent gravel, 5 percent cobbles, and 3 percent stones; neutral (pH 6.8); clear wavy boundary. (6 to 10 inches thick)
Bw1--8 to 21 inches; very dark brown (10YR 2/2) very cobbly clay loam, dark brown (10YR 3/3) dry; moderate very fine and fine subangular blocky structure; slightly hard, firm, slightly sticky and slightly plastic; common fine and medium, and few coarse roots; few fine tubular pores; 15 percent gravel and 40 percent cobbles; neutral (pH 6.8); clear wavy boundary.
Bw2--21 to 28 inches; dark brown (10YR 3/3) extremely cobbly clay loam, brown (10YR 4/3) dry; weak fine and medium subangular blocky structure; hard, firm, slightly sticky and plastic; common fine and medium, and few coarse roots; few medium tubular pores; 40 percent gravel and 25 percent cobbles; neutral (pH 6.8); abrupt wavy boundary. (Combined thickness of the Bw horizon is 14 to 30 inches)
R---28 inches; fractured serpentinized metasedimentary rock.
TYPE LOCATION: Curry County, Oregon; located about 800 feet south and 1,400 feet east of the northwest corner of section 31, T. 36 S., R. 14 W. (Latitude 42 degrees, 25 minutes, 23 seconds N.; Longitude 124 degrees, 24 minutes, 36 seconds W.)
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 51 to 54 degrees F. The difference between mean summer and mean winter soil temperatures varies from 5 to 9 degrees F. The soils are usually moist but are dry for less than 45 consecutive days in all parts between depths of 4 and 12 inches in the four months following the summer solstice. The particle-size control section averages 27 to 35 percent clay and 35 to 80 percent total rock fragments. Depth to bedrock and solum thickness is 20 to 40 inches. Soil reaction is moderately acid to neutral throughout. Hue is 10YR or 7.5YR. The mollic epipedon is 20 to 30 inches thick and may include all or part of the Bw horizon.
The A horizon has value of 2 or 3 moist, 3 or 4 dry and chroma of 2 or 3 moist and dry. It is gravelly clay loam averaging 27 to 30 percent clay. It has 15 to 20 percent gravel, 0 to 10 percent cobbles, and 0 to 3 percent stones.
The Bw horizon has value of 2 to 4 moist, 3 to 5 dry and chroma of 2 to 4 moist and dry. It is very cobbly clay loam, very gravelly silty clay loam, or extremely cobbly clay loam averaging 27 to 35 percent clay. It has 15 to 40 percent gravel, 20 to 40 percent cobbles, and 0 to 5 percent stones.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Rustybutte soils occur on metastable broad ridgetops and active side slopes of coastal hills and mountains. Slopes are 0 to 60 percent. The soils formed in colluvium and residuum derived from serpentinized metasedimentary or serpentinized metavolcanic rock types. Elevations are 200 to 1,000 feet. The climate is characterized by cool, wet winters and cool, moist summers with fog. A strong marine influence limits the diurnal and annual range of temperature. The mean annual precipitation is 75 to 95 inches. The mean annual temperature is 50 to 53 degrees F. The frost-free period is 200 to 270 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Sebastian soils, which occur on broad ridgetops and side slopes of coastal hills and mountains. Sebastian soils are 10 to 20 inches deep to bedrock.
DRAINAGE AND PERMEABILITY: Well drained; moderately slow permeability.
USE AND VEGETATION: Rustybutte soils are used for watershed, recreation, woodland, and wildlife habitat. The native vegetation is Douglas fir, Port-Orford cedar, Sitka spruce, California laurel, western swordfern, western brackenfern, sweetscented bedstraw, bentgrass, and common velvetgrass.
DISTRIBUTION AND EXTENT: Coastal hills and mountains of southwestern Oregon; MLRA 1. The series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Curry County, Oregon, 1995. The source of the name is Rusty Butte in northern Curry County.
REMARKS: Diagnostic horizons and features recognized in this pedon include:
Mollic epipedon - from the surface to a depth of 28 inches (A, Bwl, Bw2 horizons). The mollic epipedon is based on lab data from the associated Sebastian series.
Particle-size control section - from 10 to 28 inches (part of Bw1 horizon, and Bw2 horizon) with a weighted average of 58 percent rock fragments.