LOCATION STEIWER OREstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Ultic Haploxerolls
TYPICAL PEDON: Steiwer silty clay loam - pasture. (Colors are for moist soil unless otherwise noted.)
Ap--0 to 6 inches; dark brown (10YR 3/3) silty clay loam, brown (10YR 5/3) dry; moderate fine subangular blocky structure parting to moderate fine granular; hard, firm, moderately sticky and moderately plastic; many very fine roots; common very fine irregular and tubular pores; 1 percent 1-2 mm shale fragments; strongly acid (pH 5.4); abrupt smooth boundary. (4 to 15 inches thick)
BA--6 to 10 inches; dark brown (10YR 3/3) clay loam, brown (10YR 5/3) dry; moderate very fine subangular blocky structure; hard, friable, moderately sticky and moderately plastic; many very fine roots; many very fine tubular pores; 15 percent 1-2 mm shale fragments; strongly acid (pH 5.3); gradual wavy boundary. (0 to 13 inches thick)
Bw1--10 to 19 inches; dark brown (10YR 3/3) clay loam, brown (10YR 5/3) dry; moderate very fine subangular blocky structure; hard, friable, moderately sticky and moderately plastic; common fine roots; many fine and very fine pores; 3 percent 1-2 mm shale fragments; strongly acid (pH 5.3); gradual wavy boundary.
Bw2--19 to 27 inches; dark yellowish brown (10YR 3/4) clay loam, brown (10YR 5/3) dry; moderate fine subangular blocky structure; hard, firm, moderately sticky and moderately plastic; few fine roots; 15 percent 1-2 mm shale fragments; strongly acid (pH 5.3); abrupt irregular boundary. (combined thickness of the Bw horizon is 7 to 27 inches)
2Crt--27 to 40 inches; strong brown (7.5YR 5/6) and reddish yellow (7.5YR 6/6) variegated and partially weathered shale with sandstone lenses; reddish brown (5YR 4/4) clay coatings in the fractures.
TYPE LOCATION: Yamhill County, Oregon; on top of hill, 1,000 feet east and 540 feet north of the Sheridan city dump; in the southwest 1/4 northwest 1/4 southwest 1/4, section 25, T. 5 S., R. 6 W.; Willamette Meridian, Sheridan, Oregon USGS 7.5 minute topographic quadrangle. Latitude 45 degrees 06 minutes 31 seconds N., Longitude 123 degrees 22 minutes 50 seconds W. NAD 27.
RANGE IN CHARACTERISTICS: The mean annual soil temperature ranges from 53 to 55 degrees F. The soils are usually moist but are dry between depths of 4 and 12 inches from 45 to 60 consecutive days following the summer solstice. Thickness of the solum and depth to a paralithic contact range from 20 to 40 inches. The mollic epipedon ranges from 10 to 20 inches. The soil has hue of 10YR or 7.5YR.
The A horizon has value of 2 or 3 moist, 4 or 5 dry and chroma of 2 or 3 moist and dry. Texture is silt loam, loam or silty clay loam with 20 to 35 percent clay. It has 0 to 5 percent gravel and 0 to 10 percent paragravel. Reaction is slightly acid to strongly acid.
The AB or BA horizon has value of 3 or 4 moist, 5 or 6 dry and chroma of 2 or 3 moist and dry. Texture is silt loam, silty clay loam, loam or clay loam with 25 to 35 percent clay. It has 0 to 5 percent gravel and 0 to 15 percent paragravel. Reaction is moderately acid or strongly acid.
The Bw horizon has value of 3 or 4 moist, 5 or 6 dry and chroma of 2 to 4 moist and dry. Texture is clay loam or silty clay loam with 27 to 35 percent clay and more than 15 percent coarser than very fine sand. It has 0 to 10 percent gravel and 0 to 5 percent cobbles. It has 0 to 20 percent paragravel in the upper part and 0 to 35 percent paragravel in the lower part. Reaction is moderately acid or strongly acid.
COMPETING SERIES: These are the Cauley, Laughlin, Maydol and Sharpshooter soils. Cauley, Maydol and Sharpshooter soils are greater than 40 inches to bedrock. Laughlin soils have a lithic contact at 20 to 40 inches and are dry for more than 90 consecutive days following the summer solstice.
GEOGRAPHIC SETTING: The Steiwer soils occur on hills and formed in loamy colluvium derived from sedimentary bedrock and mixed with glaciolacustrine deposits at elevations below 400 feet. Some pedons overlie partially consolidated igneous bedrock. Elevation is 250 to 1,200 feet. Slopes are 3 to 50 percent. The mean annual precipitation is 40 to 60 inches. The climate is characterized by warm, wet winters and hot, dry summers. The mean July temperature is 66 to 68 degrees F, mean January temperature is 39 degrees F, and mean annual temperature is 50 to 54 degrees F. The frost-free period is 165 to 210 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Chehulpum,
Dupee,
Hazelair,
Helmick,
Willakenzie, and
Yamhill soils. Chehulpum soils are 10 to 20 inches deep to sedimentary bedrock and are on the convex parts of the hillslope. Dupee soils are greater than 40 inches to a paralithic contact and are on
footslopes and concave parts of the hillslopes. Hazelair and Helmick soils are very fine, have redox depletions within 30 inches of the surface and are on less convex parts of the hillslope. Willakenzie soils have an argillic horizondo not have a mollic epipedon and are on low hills. Yamhill soils are fine textured, have a mollic epipedon thicker than 20 inches and occur over basalt on hills.
DRAINAGE AND PERMEABILITY: Well drained; moderately slow permeability.
USE AND VEGETATION: These soils are used mainly for production of improved pasture, small grains and a few orchards. Native vegetation is annual and perennial grasses, Oregon white oak, rosebush, and poison-oak.
DISTRIBUTION AND EXTENT: Willamette Valley, Oregon. MLRA 2. The series is moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Yamhill County, Oregon, 1974.
REMARKS: Diagnostic horizons and features recognized in this pedon include:
Mollic epipedon - the zone from the soil surface to 19 inches (Ap, BA and Bw1 horizons)
Cambic horizon - the zone from 19 to 27 inches (Bw horizon)
Ultic feature - has base saturation (sum) of 75 percent or less in one or more horizons between 10 and 27 inches.
ADDITIONAL DATA: Characterization data on two profiles (S62Oreg-36-7 and 8) reported in Riverside Soil Survey Laboratory report for soils sampled in Yamhill County, Oregon, 1962. Data on profile, S62Oreg-36-7, reported in the Soil Survey of Yamhill Area report published in 1974. National Soil Survery Lab soil survey sample numbers include: S62OR-071-007 and S62OR-071-008.