LOCATION CHEHALEM OREstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Cumulic Vertic Endoaquolls
TYPICAL PEDON: Chehalem silty clay loam, cultivated. (Colors are for moist soil unless otherwise noted.)
Ap--0 to 7 inches; very dark brown (10YR 2/2) silty clay loam, dark gray (10YR 4/1) dry; moderate very fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; few fine and very fine tubular pores; 1 percent 1-2 mm weathered siltstone particles; moderately acid (pH 5.6); abrupt clear boundary. (6 to 9 inches thick)
A--7 to 11 inches; very dark brown (10YR 2/2) silty clay loam, dark gray (10YR 4/1) dry; weak very fine subangular blocky structure; slightly hard, firm, slightly sticky and moderately plastic; many fine and very fine roots; many very fine tubular pores; 1 percent 1-2 mm weathered siltstone particles; moderately acid (pH 5.8); abrupt smooth boundary. (4 to 8 inches thick)
AB--11 to 23 inches; very dark brown (10YR 2/2) silty clay loam, dark grayish brown (10YR 4/2) dry; moderate fine subangular blocky structure that parts to moderate fine granular; slightly hard, firm, moderately sticky and moderately plastic; many very fine roots; many fine and very fine tubular pores; 1 percent 1-2 mm weathered siltstone particles; moderately acid (pH 5.8); clear smooth boundary. (0 to 14 inches thick)
Bw1--23 to 36 inches; very dark grayish brown (10YR 3/2) silty clay, grayish brown (10YR 5/2) dry moderate fine subangular blocky structure; hard, firm, moderately sticky and moderately plastic; few very fine roots; many very fine tubular pores; few faint darker colored coatings on vertical surfaces of peds; 5 percent light colored siltstone paragravel; many fine prominent yellowish and reddish brown (5YR 5/4) masses of iron accumulation; moderately acid (pH 6.0); clear smooth boundary. (6 to 16 inches thick)
Bw2--36 to 49 inches; very dark brown (10YR 2/2) silty clay, dark grayish brown (10YR 4/2) dry; weak fine subangular blocky structure; very hard, moderately firm, moderately sticky and moderately plastic; many very fine tubular pores; few faint coatings on vertical surfaces of peds; 1 percent siltstone paragravel; many fine prominent yellowish brown (10YR 5/6) and reddish brown (5YR 5/4) masses of iron accumulation; moderately acid (pH 5.8); gradual smooth boundary. (8 to 19 inches thick)
C--49 to 60 inches; very dark grayish brown (10YR 3/2) silty clay, dark grayish brown (10YR 4/2) dry massive; very hard, firm, moderately sticky and moderately plastic; few very fine tubular pores; 10 percent 1-2 mm weathered siltstone particles and 10 percent siltstone paragravel; few fine prominent reddish brown (5YR 5/4) masses of iron accumulation; moderately acid (pH 6.0).
TYPE LOCATION: Yamhill County, Oregon; about 500 feet west and 1,600 feet south of the NE corner of section 6, T. 3 S., R. 3 W., Willamette Meridian. . (Latitude 45 degrees, 20 minutes, 29 seconds N. and Longitude 123 degrees, 05 minutes, 43 seconds W. NAD27.) Dundee, Oregon USGS 7.5 minute topographic quadrangle
RANGE IN CHARACTERISTICS: The mean annual soil temperature ranges from 52 to 56 degrees F. The soils are usually moist and are saturated with water at some time at a depth of 16 to 20 inches. The solum ranges from 30 to 60 inches thick. The mollic epipedon is more than 24 inches thick. The pscs has 35 to 50 percent clay, 0 to 5 percent gravel and 0 to 10 percent paragravel. Reaction is moderately acid or slightly acid.
The A horizon has hue of 10YR to 7.5YR, value of 2 or 3 moist, 3 to 5 dry and chroma of 1 or 2 moist and dry. Texture is silt loam or silty clay loam with 25 to 35 percent clay. It has 0 to 5 percent gravel and 0 to 5 percent paragravel.
The AB or BA horizon has hue of 10YR, value of 2 or 3 moist, 4 or 5 dry and chroma of 2 or 3 moist and dry. Texture is silty clay loam with 30 to 40 percent clay. It has 0 to 5 percent gravel and 0 to 5 percent paragravel.
The Bw1 horizon has hue of 10YR or 2.5Y, value of 2 to 4 moist, 4 or 5 dry and chroma of 2 or 3 moist and dry. Texture is silty clay loam, silty clay or clay with 35 to 50 percent clay. It has 0 to 5 percent gravel and 0 to 10 percent paragravel. Redox concentrations range from distinct to prominent.
The Bw2 horizon has hue of 10YR or 2.5Y, value of 2 to 4 moist, 4 to 6 dry and chroma of 2 to 4 moist and dry. Texture is silty clay or clay with 40 to 50 percent clay. It has 0 to 5 percent gravel and 0 to 15 percent paragravel. Redox concentrations range from distinct to prominent.
The C horizon has hue of 10YR or 2.5Y, value of 3 or 4 moist, 4 to 6 dry and chroma of 2 to 4 moist and dry. Texture is silty clay loam, clay loam, silty clay or clay with 30 to 50 percent clay. It has 0 to 5 percent gravel and 0 to 35 percent paragravel. Redox concentrations range from distinct to prominent.
COMPETING SERIES: These are the
Clamo,
Derrynane,
Okoboji,
Peotone,
Rantoul,
Shiloh,
Southbrook (T),
Wabash,
Zoe, and
Zook soils.
Clamo soils: depth to carbonates is 14 to 30 inches
Derrynane soils: depth to carbonantes is 40 to 80 inches; depth to glacial till is 30 to 50 inches
Okoboji soils: depth to carbonates is 25 to 40 inches; Bg horizon with hue of 2.5Y or 5Y and soil reaction of neutral to slightly alkaline; very poorly drained
Peotone soils: depth to carbonates is 30 inches or more; very poorly drained; on Wisconsinian age till plain
Rantoul soils: depth to carbonates is 34 to 60 inches; very poorly drained; on Wisonsinian age till plain
Shiloh soils: depth to carbonates is 39 inches or more; very poorly drained; depth to buried buried paleosol is 30 to 75 inches; on Illinoisan age ground moraine
Southbrook soils: not able to compete as OSD is not yet in database.
Wabash soils: depth to carbonates is 40 inches or more; poorly or very poorly drained; on flood plains
Zoe soils: depth to carbonates is 10 to 24 inches; sodium absorption ratio of 10 to 35 in the series control section; poorly and very poorly drained
Zook soils: depth to carbonates is 60 inches or more; chroma of 1 or less throughout the pscs; poorly drained
GEOGRAPHIC SETTING: The Chehalem soils are on terraces and smooth, convex alluvial fans formed at the mouth of small, usually intermittent streams that have cut through sedimentary and volcanic rock hills. Slopes are 0 to 12 percent. Elevation ranges from 150 to 900 feet. The climate is characterized by warm, wet winters and hot, dry summers. The average July temperature is 66 degrees F. and the average January temperature is 39 degrees F. The mean annual temperature is 50 to 54 degrees F. The mean annual precipitation is 40 to 60 inches. The frost-free period is 165 to 210 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Carlton, Cove, Goodin, Jory, Melbourne, Waldo, Wellsdale, Willakenzie, and Woodburn soils. Carlton soils are fine-silty and are on,terraces, footslopes, and toeslopes. Cove soils are poorly drained and are on fans and terraces. Goodin soils are 20 to 40 inches to a paralithic contact and are on higher hillslopes. Jory soils are well drained and have 5YR or 2.5YR Bt horizons and are on higher hillslopes. Melbourne soils are well drained and have 10YR and 7.5YR Bt horizons and are on higher hillslopes. Waldo soils are poorly drained and are on flood plains. Wellsdale soils are fine-loamy and are on higher hillslopes. Willakenzie soils are 20 to 40 inches to a paralithic contact and are on higher hillslopes. Woodburn soils are fine-silty and are on lower terraces.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; slow permeability. An apparent water table is at its uppermost limit from December to April.
USE AND VEGETATION: Most of these soils are cultivated. Grain, hay, and pasture are some major crops. Some corn, hazelnuts, and grass seed are also grown. Principal native plants are grasses, baldhip rose, Pacific poison oak and Oregon white oak.
DISTRIBUTION AND EXTENT: Along the foot of low hills in the western part of the Willamette Valley, Oregon; MLRA 2. The series is moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Yamhill County, Oregon, 1972.
REMARKS: Diagnostic horizons and features recognized in this pedon include:
Mollic epipedon - the zone from the soil surface to 49 inches. (Ap, A, AB, Bw1, and Bw horizons) with assumed irregular decrease in organic matter (cumulic).
Aquic feature - aquic conditions between 16 and 20 inches at some time during the year and chroma of 2 with distinct redox concentrations in the lower part of the mollic epipedon.
Vertic feature - an estimated linear extensibility of more than 6.0 cm between 0 and 40 inches.
ADDITIONAL DATA: Characterization data from a representative pedon with User Pedon ID # 99OR071001