LOCATION SHIVIGNY OREstablished Series
TAXONOMIC CLASS: Clayey-skeletal, mixed, active, mesic Typic Palehumults
TYPICAL PEDON: Shivigny very gravelly loam, woodland. (Colors are for moist soil unless otherwise noted.)
A--0 to 5 inches; dark reddish brown (5YR 3/4) very gravelly loam, reddish brown (5YR 5/4) dry; moderate fine granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine roots; many very fine tubular pores; 50 percent gravel and 5 percent cobbles; moderately acid (pH 5.6); clear wavy boundary. (4 to 7 inches thick)
AB--5 to 10 inches; dark reddish brown (5YR 3/4) very gravelly loam, light reddish brown (5YR 6/4) dry; strong medium granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine to medium roots; many very fine tubular pores; 35 percent gravel; moderately acid (pH 5.6); clear irregular boundary. (4 to 8 inches thick)
BA--10 to 21 inches; yellowish red (5YR 4/6) very stony clay loam, reddish yellow (5YR 6/6) dry; moderate medium subangular blocky structure with pockets of strong medium granular; hard, friable, moderately sticky and moderately plastic; common very fine to coarse roots; common very fine tubular and many fine medium irregular pores; 25 percent stones, 15 percent cobbles, and 10 percent gravel; strongly acid (pH 5.2); clear wavy boundary. (8 to 15 inches thick)
Bt1--21 to 33 inches; yellowish red (5YR 4/6) very stony clay, strong brown (7.5YR 5/6) dry; strong medium angular and subangular blocky structure; very hard, firm, very sticky and very plastic; few very fine to coarse roots; common very fine tubular and many fine and medium irregular pores; few distinct clay films on faces of peds; 30 percent stones, 20 percent cobbles, and 5 percent gravel; very strongly acid (pH 5.0); gradual irregular boundary.
Bt2--33 to 47 inches; yellowish red (5YR 4/6) very stony clay, strong brown (7.5YR 5/6) dry; strong medium angular and subangular blocky structure; very hard, firm, very sticky and very plastic; few very fine to medium roots; few very fine tubular and common fine and medium irregular pores; many distinct clay films on faces of peds; 25 percent stones, 15 percent cobbles, and 10 percent gravel; very strongly acid (pH 4.8); gradual irregular boundary. (Combined thickness of the Bt horizon is 20 to 55 inches)
BCt--47 to 64 inches; variegated yellowish red (5YR 4/6) and reddish brown very stony clay, mixed reddish brown (5YR 4/4) and strong brown (7.5YR 5/6) dry; weak medium subangular blocky structure; very hard, firm, very sticky and very plastic; very few fine roots; very few fine tubular pores; many distinct clay films on faces of peds; common moderately thick black coatings on ped faces; 30 percent stones, 15 percent cobbles, and 10 percent gravel; very strongly acid (pH 4.8).
TYPE LOCATION: Douglas County, Oregon. The site is located 925 feet east and 50 feet north of the SW corner of section 19, T. 27 S., R. 2 W.; Red Butte, OR 7.5 minute USGS Quad; NAD 1927
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 47 to 56 degrees F. The soil is usually moist and is dry between depths of 4 and 12 inches for less than 45 consecutive days in the four-month period following the summer solstice in most years. The thickness of the solum and depth to bedrock are commonly 5 feet or more but in some pedons the solum may be as thin as 40 inches. The pscs has 35 to 70 percent rock fragments and 35 to 70 percent clay. Reaction is moderately acid to very strongly acid with the pH decreasing with depth.
The A horizon has hue of 5YR or 7.5YR, value of 3 or 4 moist, 5 or 6 dry and chroma of 3 or 4 moist and dry. Texture is very gravelly loam or very gravelly clay loam with 18 to 35 percent clay. It has 25 to 60 percent gravel and 0 to 10 percent cobbles.
The AB or BA horizon has hue of 5YR or 7.5YR, value of 3 or 4 moist, 5 or 6 dry and chroma of 4 to 6 moist and dry. Texture is very gravelly loam, extremely gravelly clay, very gravelly clay loam, or very stony clay loam with 25 to 50 percent clay.
The Bt horizon and BCt horizon when present has hue of 2.5YR to 7.5YR, value of 3 or 4 moist and 5 or 6 dry, and chroma of 4 to 8 moist and dry. Texture of the fine-earth fraction is clay, silty clay, or clay loam with 35 to 55 percent clay. It has 5 to 50 percent gravel, 0 to 40 percent cobbles, and 5 to 40 percent stones. Total rock fragment content is 35 to 70 percent.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Shivigny soils are on old slumps benches, shoulder slopes, and back slopes of mountains. Elevations are 300 to 3,200 feet. Slopes are 3 to 90 percent. These soils have formed in clayey colluvium and residuum derived dominantly from basalt, tuffs, breccias, and andesites with some areas of metasedimentary or other igneous rock types. The climate is characterized by warm wet winters and hot moist summers. The mean annual precipitation is typically 50 to 90 inches but may range to 110 inches in high winter rainfall interior mountains of southwestern Oregon. The mean annual temperature is 45 to 55 degrees F. The mean January temperature is about 37 degrees F. and the mean July temperature is about 63 degrees F. The frost-free period is 100 to 220 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Gustin, Harrington, Honeygrove, Klickitat, Kilchis, and Peavine series. All of these soils occur on mountains. The Harrington, Klickitat, and Kilchis soils are loamy-skeletal. Honeygrove and Peavine soils have less than 35 percent rock fragments in the particle-size control section. Gustin soils have less than 35 percent rock fragments in the particle-size control section and are moderately well to somewhat poorly drained.
DRAINAGE AND PERMEABILITY: Well drained; moderately slow permeability.
USE AND VEGETATION: The soils are used for timber production, recreation, wildlife habitat and watersheds. Native vegetation is Douglas fir, western redcedar, grand fir, red huckleberry, western swordfern, salal and cascade Oregongrape. Minor amounts of western hemlock may also be present in some areas.
DISTRIBUTION AND EXTENT: Western slopes of the Cascade Mountains in southern Oregon, eastern slopes of the central portion of the Coast Range Mountains, and the northern margin of the Klamath Mountains Province in southwestern Oregon; MLRA 1, 3. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Douglas County, Oregon, 1994. The name is taken from Shivigny Mountain in Douglas County.
REMARKS: Diagnostic horizons and features include:
Argillic horizon - the zone from 21 to 64 inches (Bt1, Bt2, and BCt horizons)
Pale feature - no clay decrease by 20 percent to a depth of 60 inches or more.
Particle-size control section - the zone from 21 to 41 inches (Bt1 and upper 14 inches of Bt2 horizon)
Classification revised 1994 from Typic Haplohumults to Typic Palehumults.
Classification revised 05/2005 from isotic to mixed, active mineralogy based on lab data and similar soils.
These soils are labeled Unit 300 in the BLM soil survey.
Depths to diagnostic horizons and features are measured from the top of the first mineral horizon.