LOCATION WHITEHORSE OREstablished Series
TAXONOMIC CLASS: Medial over loamy, amorphic over isotic Typic Haplocryands
TYPICAL PEDON: Whitehorse loam, meadow. (Colors are for moist soil unless otherwise noted.)
Oi--1 inch to 0; partially decomposed organic matter and fine roots.
A1--0 to 12 inches; very dark brown (10YR 2/2) loam, dark grayish brown (10YR 4/2) dry; weak very fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine roots; 5 percent fine pumice; strongly acid (pH 5.2); gradual wavy boundary.
A2--12 to 20 inches; very dark brown (10YR 2/2) loam, dark grayish brown (10YR 4/2) dry; weak very fine granular structure; soft, very friable, nonsticky and nonplastic; many fine roots; many very fine irregular pores; 5 percent fine pumice; very strongly acid (pH 5.0); gradual wavy boundary.
A3--20 to 29 inches; very dark brown (10YR 2/2) loam, dark grayish brown (10YR 4/2) dry; weak very fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine roots; many very fine irregular pores; 5 percent fine pumice; very strongly acid (pH 5.0); abrupt wavy boundary. (Combined thickness of the A horizon is 20 to 34 inches)
2Bw--29 to 36 inches; dark yellowish brown (10YR 3/4) gravelly clay loam, brown (10YR 5/3) dry; moderate fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; many very fine and fine pores; 5 percent fine pumice; 20 percent partially weathered basic igneous gravel and cobbles; 5 percent cobbles; very strongly acid (pH 4.7); clear wavy boundary. (4 to 8 inches thick)
2C--36 to 58 inches; dark brown (7.5YR 3/2) and dark yellowish brown (10YR 3/4) gravelly clay loam, brown (7.5YR 5/2) dry; massive; slightly hard, friable, slightly sticky and slightly plastic; few thin clay films in voids near bedrock; few fine roots; many fine pores; 5 percent fine pumice and 25 percent weathered basic igneous gravel and 5 percent cobbles; very strongly acid (pH 4.9); abrupt wavy boundary. (15 to 40 inches thick)
3R--58 inches; fractured basic igneous rock.
TYPE LOCATION: Douglas County, Oregon; about 1/4 mile mile north of Mud Lake, near Mud Mountain; NW1/4 SE1/4 section 30, T.27S., R.3E.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 40 to 45 degrees F. and the mean summer soil temperature is less than 47 degrees F. with an 0 horizon. The soils are usually moist but are dry during a part of the summer. Depth to bedrock ranges from 40 to 60 inches or more. Thickness of the solum ranges from 25 to 40 inches and the thickness of the A horizon ranges from 24 to 32 inches. Rock fragments are commonly absent in the A horizon and range from 15 to 25 percent gravel and 0 to 10 percent cobbles in the B and C horizon.
The A horizon has value of 2 moist and 4 or 5 dry and chroma of 1 or 2 moist and dry. Moist value of 3 is below 20 inches in some pedons. It has a phosphate retention of 90 to 100 percent and acid oxalate extractable aluminum plus one-half iron of 2.0 to 3.0 percent. Organic matter is 5 to 10 percent.
The 2Bw horizon has value of 3 or 4 moist and 5 or 6 dry and chroma of 3 or 4 moist and dry. It is gravelly clay loam or gravelly loam and has 20 to 35 percent clay.
The 2C horizon has hue of 7.5YR or 10YR, value of 3 or 4 moist and 5 or 6 dry and chroma of 2 through 4 moist and dry. It has range in texture similar to that of the B horizon.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: The Whitehorse soils are in mountain meadows and bordering uplands at elevations of 4,000 to 7,000 feet. Slopes are 0 to 40 percent. The soils formed in ash and alluvium and colluvium weathered from basalt and other basic igneous rocks. The climate is characterized by cold wet winters and cool moist summers. The mean annual precipitation is 60 to 90 inches. The mean annual temperature is 38 to 43 degrees F.; the mean annual January temperature is about 25 degrees F.; and the mean July temperature is about 55 degrees F. The frost-free period is 40 to 80 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Hummington and Snowlin soils. Hummington soils are medial-skeletal and are 20 to 40 inches deep to bedrock. Snowlin soils are on associated steeper slopes, are fine-loamy, and lack andic soil properties.
DRAINAGE AND PERMEABILITY: Well drained; moderately slow permeability.
USE AND VEGETATION: Water supply, wildlife habitat,and recreation. The vegetation is mountain meadow plants of ferns, herbs and grasses.
DISTRIBUTION AND EXTENT: West side of central and southern Cascade Mountains, Oregon; MLRA 3.5.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Douglas County, Oregon, 1975.
REMARKS: This draft reflects a change in classification from Medial over loamy, mixed Typic Cryandepts based on the Andisol Order.
Diagnostic horizons and features recognized in this pedon:
Pachic feature - from 0 to 29 inches (A1, A2, and A3 horizons)
Cambic horizon - from 29 to 36 inches (2Bw horizon)
Particle-size control section - from surface to 40 inches (A1, A2, A3, 2Bw, and upper 4 inches of 2C horizon)
Andic soil properties - from the surface to 29 inches based on laboratory data from associated Hummington soil.
ADDITIONAL DATA: Characterization data for one profile reported in the Soil Survey of South Umpqua Area, Oregon, 1973. Analyses by Oregon State University.