LOCATION PERDIN OREstablished Series
TAXONOMIC CLASS: Fine, magnesic, frigid Ultic Haploxeralfs
TYPICAL PEDON: Perdin cobbly loam, on a southeast-facing slope of 42 percent under mixed conifers at 4,000 feet elevation. (When described the soil was moist throughout. Colors are for moist soil unless otherwise noted.)
0i--2 inches to 0; leaves, needles, and twigs overlying highly decomposed forest litter.
A--0 to 7 inches; dark reddish brown (2.5YR 3/4) cobbly loam, reddish brown (2.5YR 4/4) dry; weak fine granular and moderate fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine and few medium and coarse roots; few very fine tubular pores; 10 percent gravel and 10 percent cobbles; slightly acid (pH 6.2); clear wavy boundary. (5 to 9 inches thick)
Bt1--7 to 12 inches; dark reddish brown (5YR 3/4) gravelly clay loam, reddish brown (5YR 4/4) crushed, strong brown (7.5YR 4/6) dry; moderate fine subangular blocky structure; slightly hard, friable sticky and plastic; many fine and few medium and coarse roots; common fine tubular pores; few faint clay films on faces of peds and in tubular pores; 15 percent gravel; neutral (pH 6.7); clear wavy boundary.
Bt2--12 to 24 inches; dark brown (7.5YR 3/4) gravelly clay loam, strong brown (7.5YR 4/6) dry; moderate fine angular blocky structure; slightly hard, friable, sticky and plastic; few roots; few fine tubular pores; few distinct clay films on faces of peds and in tubular pores; 25 percent gravel; neutral (pH 7.1); abrupt wavy boundary. (Combined Bt horizon is 14 to 35 inches thick)
Cr--24 to 27 inches; weathered serpentine.
TYPE LOCATION: Josephine County, Oregon; about 5 miles west of Onion Mountain Lookout; approximately 2,040 feet east and 2,600 feet north of the southwest corner of section 2, T. 36 S., R. 9 W.
RANGE IN CHARACTERISTICS: The soils are usually moist but are dry for 45 to 60 consecutive days following the summer solstice between depths of 4 and 12 inches. Depth to the paralithic contact is 20 to 40 inches. The mean annual soil temperature is 42 to 47 degrees F. Rock fragments in the particle-size control section average 15 to 25 percent gravel and 0 to 10 percent cobbles. Hue is 2.5YR, 5YR, or 7.5YR.
The A horizon has value of 3 or 4 moist, 4 or 5 dry and chroma of 4 to 6 moist and dry. Rock fragments average 10 to 20 percent cobbles and 5 to 15 percent gravel.
The Bt horizon has value of 3 or 4 moist, 4 or 5 dry and chroma of 4 or 5 moist, 4 to 6 dry. It is clay loam or clay and averages 35 to 45 percent clay. It has 15 to 25 percent gravel and 0 to 10 percent cobbles.
COMPETING SERIES: There are no competing series. Similar soils in other families include the Dubakella and Weitchpec series. These soils have mesic soil temperatures and are skeletal. Weitchpec soils also lack an argillic horizon.
GEOGRAPHIC SETTING: The Perdin soils are on broad ridgetops and side slopes of mountains. Elevations are 3,000 to 5,500 feet. Slopes are 5 to 90 percent. The soils formed in colluvium and residuum weathered from serpentinitic rocks and peridotite. The climate is characterized by cold moist to wet winters and hot dry summers. The mean annual temperature is about 40 to 45 degrees F. The mean annual precipitation is typically 40 to 70 inches but in areas of high winter rainfall may range to 120 inches. The frost-free season is 60 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Althouse, Jayar, Pearsoll, and Woodseye soils and the competing Dubakella soils. Althouse, Jayar, and Woodseye soils have mixed mineralogy, are skeletal and lack an argillic horizon. Pearsoll soils have mesic soil temperatures, are loamy-skeletal, lack an argillic horizon and are 10 to 20 inches deep. All of these soils occur on ridgetops and side slopes of mountains.
DRAINAGE AND PERMEABILITY: Well drained; slow permeability.
USE AND VEGETATION: Perdin soils are used for wildlife habitat and watershed. Native vegetation is Jeffrey pine, incense-cedar, greenleaf manzanita, beargrass, other shrubs and grasses. In the high winter rainfall areas of Curry County, Oregon native vegetation includes western white pine, knobcone pine, sugar pine, tanoak, canyon live oak, and huckleberry oak.
DISTRIBUTION AND EXTENT: Mountainous areas of southwestern Oregon; MLRA 5. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Josephine County, Oregon, 1979.
ADDITIONAL DATA: Characterization data for one pedon S77-OR-33-2(1-3) by the OSU soils laboratory (unpublished).
REMARKS: Diagnostic horizons and features include:
Ochric epipedon
Argillic horizon and particle-size control section - the zone from 7 to 24 inches (Bt1 and Bt2 horizons)
Ultic feature - from 7 to 12 inches (Bt1) having a base saturation (sum) of 39 percent; from 12 to 24 inches (Bt2) having a base saturation (sum) of 69 percent