LOCATION DOMPIER OREstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Aquic Fragixeralfs
TYPICAL PEDON: Dompier silt loam-forested, on a southwest-facing slope of 35 percent at an elevation of 1550 feet. (Colors are for moist soil unless otherwise stated.)
Oi--2 inches to 0; slightly decomposed needles, leaves, and twigs.
A--0 to 6 inches; dark brown (10YR 3/3) silt loam, pale brown (10YR 6/3) dry; moderate fine and medium granular structure; hard, friable, slightly sticky and slightly plastic; many very fine, fine, and medium roots; strongly acid (pH 5.4); clear wavy boundary. (5 to 7 inches thick)
AB--6 to 16 inches; dark brown (10YR 3/3) silt loam, pale brown (10YR 6/3) dry; moderate fine subangular blocky structure; hard, firm, sticky and slightly plastic; many very fine, fine, and medium roots; few medium irregular pores; strongly acid (pH 5.4); clear wavy boundary. (5 to 10 inches thick)
Bt--16 to 24 inches; dark brown (10YR 4/3) silt loam, light brownish gray (10YR 6/2) dry; moderate medium subangular blocky structure; hard, friable, sticky and slightly plastic; common very fine and fine, and few medium roots; many very fine and few medium irregular pores; few faint clay films on faces of peds and in pores; common fine faint brown (10YR 5/3) masses of iron accumulation, yellowish brown (10YR 5/4) dry; moderately acid (pH 5.6); clear wavy boundary. (8 to 15 inches thick)
Btg--24 to 32 inches; gray (10YR 5/1) silty clay loam, light brownish gray (10YR 6/2) dry; strong medium and coarse subangular blocky structure; very hard, very firm, sticky and plastic; common very fine and fine roots along faces of peds; many very fine irregular pores; common distinct clay films on faces of peds and in pores; many medium distinct dark grayish brown (10YR 4/2) masses of iron accumulation; slightly acid (pH 6.2); abrupt wavy boundary. (0 to 8 inches thick)
Btx--32 to 60 inches; dark yellowish brown (10YR 3/6) silt loam, light yellowish brown (10YR 6/4) dry; strong very coarse prismatic structure; extremely hard, extremely firm, brittle, sticky and plastic; very few very fine roots along faces of peds in upper 6 inches; many fine irregular pores; common distinct clay films on faces of peds and in pores; 45 percent light olive brown (2.5Y 5/4) iron depleted ped faces, light gray (2.5Y 7/2) dry and 15 percent dark yellowish brown (10YR 4/6) masses of iron accumulaiton, yellowish brown (10YR 5/6) dry; neutral (pH 6.8).
TYPE LOCATION: Douglas County, Oregon, 1 mile south of Milo, Oregon, 1200 feet south of the northeast corner of section 8, T.31 S., R. 3 W., W.M. (Latitude 42 degrees, 53 minutes, 50 seconds N, Longitude 123 degrees, 4 minutes, 15 seconds W)
RANGE IN CHARACTERISTICS: Solum thickness and depth to bedrock is 60 inches or more. Depth to the fragipan is 20 to 40 inches. The mean annual soil temperature is 49 to 56 degrees F. The soil is usually moist but is dry within all parts of the moisture control section for 45 to 60 consecutive days following the summer solstice. The particle-size control section has 20 to 30 percent clay and 10 to 15 percent sand that is coarser than very fine. Depth to redoximorphic depletions having chroma of 2 or less is 18 to 30 inches.
The A horizon has hue of 10YR or 2.5Y, value of 2 to 4 moist and 5 or 6 dry, and chroma of 2 to 4 moist and dry. Clay content is 10 to 15 percent. It has 0 to 15 percent gravel. It is slightly acid to strongly acid.
The Bt horizon has hue of 10YR or 2.5Y moist, value of 4 or 5 moist, 6 or 7 dry, and chroma of 1 to 3 moist and dry. It is silt loam or silty clay loam with 20 to 30 clay. It has 0 to 10 percent gravel. It is slightly acid to strongly acid.
The Btx horizon has matrix hue of 10YR or 2.5Y, value of 3 to 5 moist, 6 or 7 dry, and chroma of 4 to 6 moist and dry. Bleached ped faces have hue of 2.5Y or 5Y, value of 4 to 6 moist, 6 to 8 dry and chroma of 1 to 4 moist and dry. It is loam or silt loam with 10 to 20 percent clay. It has 0 to 15 percent gravel. It is strongly acid to neutral.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Dompier soils are on mountain sideslopes, benches and foot slopes. They formed in residuum and colluvium derived dominantly from schist and other metasedimentary rocks and to some extent, from granodiorite. Slopes are 30 to 60 percent. Elevations are 1100 to 2800 feet. The climate is characterized by warm, wet winters and hot, dry summers. The mean annual temperature ranges from 45 to 54 degrees F, and the mean annual precipitation is 35 to 60 inches. The frost free period is 100 to 200 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Beal, Dumont, Lettia, Sharpshooter, Sweetbriar, and Zing soils. All of these soils lack a fragipan. Dumont soils are kaolinitic. Lettia soils are well drained. Sweetbriar, and Zing soils are fine textured. Sharpshooter soils lack an argillic horizon.
DRAINAGE AND PERMEABILITY: Moderately well drained; Permeability is moderate above the fragipan and very slow within the fragipan. The water table is perched above the fragipan from November through March.
USE AND VEGETATION: These soils are used for timber production, wildlife habitat, and watershed. The native vegetation includes Douglas fir, incense cedar, Pacific madrone, and ponderosa pine with an understory of common snowberry, American trailplant, whipplevine, wild rose, Pacific poison oak, salal, western rattlesnake plantain, and creambush oceanspray.
DISTRIBUTION AND EXTENT: Southwestern Oregon, MLRA 5. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Douglas County, Oregon, 1994.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - from the surface of the soil to 10 inches. (A and AB horizons), organic matter is less than 1 percent below 5 inches. Clay content of the AB horizon is 15 percent.
Argillic horizon - from 16 to 32 inches. (Bt and Btg horizons), clay content of the Bt and Btg is 23 and 26 percent respectively.
Fragipan - from 32 to 60 inches. (Btgx horizon)
Particle-size control section - from 16 to 32 inches. (Bt and Btg horizons), averages 24 percent clay, 61 percent silt and 15 percent sand.
The superactive cation exchange activity class was added to the classification in 10/2005. The competing series section was not updated at that time. Last revision 3/1995.
ADDITIONAL DATA: Partial laboratory data is available for this pedon. Reference sample S86OR019-002 from Douglas County, Oregon. NSSL, Lincoln, NE, 1/87.