LOCATION BENTILLA OREstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, isomesic Typic Palehumults
TYPICAL PEDON: Bentilla silty clay loam, 3 to 12 percent slopes, forested. (Colors are for moist soil unless otherwise noted.)
0i--2 inches to 0; duff - needles, leaves, roots, twigs, and moss.
A1--0 to 3 inches; very dark brown (10YR 2/2) silty clay loam, dark grayish brown (10YR 4/2) dry, moderate fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; many fine and very fine roots; many very fine irregular pores; very strongly acid (pH 4.6); clear smooth boundary. (2 to 4 inches thick)
A2--3 to 9 inches; very dark grayish brown (10YR 3/2) silty clay loam, brown (10YR 4/3) dry; moderate very fine subangular blocky structure; hard, firm, slightly sticky and slightly plastic; common fine and very fine roots; many very fine tubular pores; very strongly acid (pH 4.6); clear wavy boundary. (4 to 7 inches thick)
AB--9 to 16 inches; dark brown (10YR 3/3) silty clay loam, brown (10YR 5/3) dry; moderate fine and very fine subangular blocky structure; slightly hard, friable, sticky and plastic; common very fine roots; many very fine tubular pores; very strongly acid (pH 4.6); abrupt wavy boundary. (0 to 10 inches thick)
Bt1--16 to 28 inches; brown (10YR 4/3) silty clay, light yellowish brown (10YR 6/4) dry; moderate fine and very fine subangular blocky structure; hard, firm, sticky and plastic; few very fine roots; many very fine tubular pores; few thin clay films on peds and in pores; very strongly acid (pH 4.6); clear smooth boundary. (10 to 15 inches thick)
Bt2--28 to 40 inches; yellowish brown (10YR 5/4) clay, very pale brown (10YR 7/4) dry; many distinct fine and very fine light brownish gray (10YR 6/2) and strong brown (7.5YR 5/6) mottles; moderate fine subangular blocky structure; hard, firm, very sticky and very plastic; few very fine roots; common very fine tubular pores; many moderately thick clay films on peds and in pores; extremely acid (pH 4.4); gradual smooth boundary. (10 to 15 inches thick)
Bt3--40 to 51 inches; light brownish gray (10YR 6/2) silty clay, light gray (10YR 7/2) dry; many fine prominent strong brown (7.5YR 5/8) mottles; weak fine prismatic structure parting to moderate fine angular blocky; common very fine tubular pores; many moderately thick clay films on peds and in pores; extremely acid (pH 4.4); clear smooth boundary. (8 to 15 inches thick)
BCtg--51 to 60 inches; gray (10YR 6/1) clay, light gray (10YR 7/1) dry; many fine and medium strong brown (7.5YR 5/8, 4/6) mottles; weak coarse angular blocky structure parting to moderate medium and fine angular blocky; common very fine tubular pores; common thin clay films on peds and in pores; extremely acid (pH 4.4).
TYPE LOCATION: Lincoln County, Oregon; about 500 feet south and 600 feet east of the NW corner of section 21, T. 9 S., R. 10 W.
RANGE IN CHARACTERISTICS: The soil is usually moist, they are dry less than 45 consecutive days between the depths of 4 and 12 inches following the summer solstice. The mean annual soil temperature is 48 to 52 degrees F. The difference between mean summer and mean winter soil temperature is less than 9 degrees F. The umbric epipedon ranges from 10 to 20 inches thick. The texture control section averages more than 35 percent clay. Moist chromas of 2 or less occur between 22 and 30 inches. Water worn gravel may occur in some pedons.
The A and AB horizons have value of 2 or 3 moist, 4 or 5 dry, and chroma of 2 or 3 moist and dry with 27 to 40 percent clay.
The Bt horizons have value of 4 through 6 moist, 5 through 7 dry and chroma of 2 through 4 moist and dry with 40 to 60 percent clay.
The BCtg horizon has hue of 10YR or 2.5Y, value of 6 or 7 moist and dry, and chroma of 1 or 2 moist and dry. It averages 35 to 60 percent clay with chroma of 2 or less within the particle-size control section and is well drained.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Bentilla soils are on nearly level to gently sloping Dolph terrace remnants along major stream systems. Elevation ranges from 100 to 400 feet. The soils formed in fine textured alluvium. The mean annual precipitation is 70 to 100 inches. The mean annual air temperature is 48 to 53 degrees F. The frost-free period is 160 to 210 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Fendal, Grindbrook, Hebo, Reedsport and Tolovana soils. Fendal soils are 20 to 40 inches thick to a paralithic contact and lack an argillic horizon. Grindbrook soils average less than 35 percent clay in the texture control section and lack an argillic horizon. Hebo soils are poorly drained and lack argillic horizons. Reedsport and Tolovana soils are on adjacent mountain areas and average less than 35 percent clay in the texture control section. Reedsport soils are 20 to 40 inches deep to a paralithic contact. Tolovana soils are dominated by bulk densities less than 0.85 grams per cubic centimeter.
DRAINAGE AND PERMEABILITY: Moderately well drained; very slow permeability.
USE AND VEGETATION: These soils are used primarily for timber production. Other uses include pastureland, wildlife habitat and homesite development. Native vegetation includes western hemlock, Sitka spruce, Douglas fir, western red alder, cascara buckthorn, bitter cherry, vine maple, red huckleberry, western swordfern, salmonberry and trailing blackberry.
DISTRIBUTION AND EXTENT: Terrace remnants of the Dolph age geomorphic surface along major streams in the isomesic zone of the Oregon coast. The series is limited in extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Lincoln County, Oregon; 1990.
REMARKS: Diagnostic horizons and features in this pedon:
Umbric epipedon - from surface to 16 inches (A1, A2, and AB horizons).
Argillic horizon - from 16 to 60 inches (Bt1, Bt2, Bt3, and BCtg horizons).
Pale feature - percentage of clay does not decrease from its maximum amount by 20 percent or more within a depth of 60 inches from the surface.