LOCATION DUPEE OREstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, mesic Aquultic Haploxeralfs
TYPICAL PEDON: Dupee silt loam, in an area of 3 to 12 percent slopes at an elevation of 290 feet. (Colors are for moist soil unless otherwise noted.)
A1--0 to 4 inches; dark brown (10YR 3/3) silt loam, brown (10YR 5/3) dry;strong fine granular and subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and few fine and medium roots; many fine irregular pores; moderately acid (pH 5.8); clear wavy boundary. (4 to 11 inches thick)
A2--4 to 9 inches; dark brown (10YR 3/3) silt loam, pale brown (10YR 6/3) dry; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots, many fine and medium irregular pores; moderately acid (pH 5.8); clear wavy boundary. (0 to 7 inches thick). clear smooth boundary. ( 4 to 10 inches thick)
AB--9 to 17 inches; dark yellowish brown (10YR 3/4) silty clay loam, pale brown (10YR 6/3) dry; moderate fine and medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; common very fine and fine roots; many very fine irregular pores; few fine distinct yellowish brown (10YR 5/6) masses of iron accumulation; very strongly acid (pH 5.0); clear wavy boundary. (0 to 10 inches)
BA--17 to 24 inches; dark yellowish brown (10YR 3/4) silty clay loam, pale brown (10YR 6/3) dry; weak medium prismatic structure; hard, firm, moderately sticky and moderately plastic; common very fine and fine roots; many fine irregular pores; few light gray (10YR 7/2) dry silt coatings on faces of peds; few fine prominent yellowish brown (10YR 5/8) masses of iron accumulation; very strongly acid (pH 5.0); clear wavy boundary. (5 to 14 inches thick)
Bt1--24 to 34 inches; brown (10YR 4/3) silty clay, pale brown (10YR 6/3) dryweak medium prismatic structure parting to moderate fine and medium subangular blocky; very hard, very firm, very sticky and very plastic; common fine roots; common very fine irregular pores; common distinct dark yellowish brown (10YR 3/4) clay films on faces of peds; common light gray (10YR 7/2) dry, silt coatings on faces of peds; few fine distinct dark grayish brown (10YR 4/2) iron depletions; few fine distinct yellowish brown (10YR 5/6) masses of iron accumulation; very strongly acid (pH 4.8); clear wavy boundary. (6 to 12 inches thick)
Bt2--34 to 42 inches; dark yellowish brown (10YR 4/4) silty clay, pale brown (10YR 6/3) dry; moderate fine and medium subangular blocky structure; very hard, very firm, very sticky and very plastic; few very fine roots; common very fine irregular pores; common distinct dark yellowish brown (10YR 3/4) clay films on faces of peds; common light gray (10YR 7/2) dry silt coatings on faces of peds; common fine distinct dark grayish brown (10YR 4/2) iron depletions; common fine distinct yellowish brown (10YR 5/6) masses of iron accumulation; common fine prominent black (10YR 2/1) manganese films; very strongly acid (pH 4.8); clear wavy boundary. (7 to 20 inches thick)
BCt--42 to 51 inches; dark grayish brown (10YR 4/2) silty clay, pale brown (10YR 6/3) dry; weak coarse subangular blocky structure; very hard, very firm, very sticky and very plastic; few very fine roots; few very fine pores; common distinct dark yellowish brown (10YR 3/4) clay films on faces of peds; common yellowish brown (10YR 5/8) masses of iron accumulation; few fine prominent black (10YR 2/1) manganese films; very strongly acid (pH 4.8); clear wavy boundary. (10 to 10 to 10 inches thick)
Cg--51 to 62 inches; grayish brown (10YR 5/2), gray (10YR 5/1), and yellowish brown (10YR 5/6) clay; massive; very hard, very firm, very sticky and very plastic; few very fine pores; 2 percent moderately cemented paragravel; very strongly acid (pH 4.8).
TYPE LOCATION: Polk County, Oregon; about 2 miles north of Dallas, Oregon about 2,600 feet east and 2,100 feet south of the NW corner of section 21, T.7S., R.5W., Willamette Meridian; Dallas, Oregon USGS 7.5 minute topographic quadrangle. Latitude 44 degrees, 57 minutes, 00 seconds N., and Longitude 123 degrees, 18 minutes, 21 seconds W.; NAD 27
RANGE IN CHARACTERISTICS: The mean annual soil temperature ranges from about 53 to 55 degrees F. The soil is usually moist but is dry in all parts between 4 and 12 inches for 45 to 60 consecutive days following the summer solstice within MLRA 2 but ranges to 90 days within MLRA 5. The particle-size control section has 35 to 50 percent clay with 0 to 5 percent rock fragments and 0 to 50 percent pararock fragments. The pararock fragments are of siltstone, sandstone, or tuffaceous origin. The solum ranges from 30 to 54 inches thick and has hue of 10YR or 7.5YR. Depth to bedrock is typically greater than 60 inches but ranges to 40 to 60 inches. Redox depletions with chroma of 2 or less and redox concentations occur at depths between 10 and 30 inches. Base saturation ranges from 40 to 50 percent in the A horizon and 50 to 70 percent in the Bt horizon.
The A horizon has value of 2 or 3 moist, 4 to 6 dry and chroma of 2 to 4 moist and dry. Texture is silt loam or silty clay loam with 15 to 35 percent clay. It has 0 to 5 percent gravel and 0 to 5 percent paragravel. Reaction is strongly acid or moderately acid.
The AB or BA horizons have value of 3 to 5 moist, 5 or 6 dry and chroma of 2 to 4 moist and 3 or 4 dry. Texture of the AB horizon is silt loam, clay loam or silty clay loam with 25 to 35 percent clay. The BA horizon is silty clay loam or clay loam with 27 to 40 percent clay. They have 0 to 5 percent gravel and 0 to 5 percent paragravel. Reaction is very strongly acid or strongly acid.
The Bt horizon has value of 4 or 5 moist, 5 to 7 dry and chroma of 3 or 4 moist, 3 to 6 dry. Texture is silty clay loam, clay loam, silty clay or clay with 35 to 50 percent clay. It has 0 to 5 percent gravel. It has 0 to 20 percent paragravel in the upper part of the Bt horizon and ranges to 50 percent in the lower part. Reaction is very strongly acid or strongly acid. Common silt coatings are on faces of peds in the lower part in some pedons.
The BCt and C horizons have hue of 7.5YR, 10YR or 2.5Y, value of 4 to 7 moist, 5 to 7 dry and chroma of 1 to 6 moist and dry. Texture is clay loam, silty clay loam, silty clay or clay with 30 to 50 percent clay. They have 0 to 5 percent gravel and 0 to 50 percent paragravel. Reaction is very strongly acid or strongly acid.
COMPETING SERIES: These are the Linslaw, Santiam, and Zing series. Linslaw soils have a stratified, very firm, clayey and sandy 2C horizon at a depth of 30 to 48 inches. Santiam soils have a 2C horizon derived from old alluvium at a depth of 30 to 40 inches and 5 to 25 percent rounded paragravel. Zing soils have an umbric epipedon, hue dominantly of 2.5Y or 5Y, are slightly acid or neutral in the Bt horizon and have a mean annual soil temperature of 47 to 52 degrees F.
GEOGRAPHIC SETTING: Dupee soils are in, depressions and drainageways on broad, gently sloping tops (summit position and interfluve component), and undulating side slopes (backslope, footslope, and toeslope positions) of hills along the margins of the Willamette Valley in Oregon. Slopes are 2 to 30 percent. Elevation is 170 to 800 feet where these soils occur on the Spencer Formation along the western margins of the Willamette Valley, 300 to 1,400 feet where these soils occur on the Eugene and Fisher formations along the eastern margin of the southern part of the Willamette Valley, and up to 2,500 feet in Douglas County. The soils formed in colluvium and residuum derived from marine tuffaceous sandstone, silstone, or mudstone of the Spencer Formation or from arkosic and micaceous sandstone, siltstone of the Eugene and Fisher Formations. The climate is characterized by warm, wet winters and hot, dry summers. The mean annual temperature is 50 to 54 degrees F. The mean annual precipitation is 40 to 60 inches. The frost-free season averages 160 to 235 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Bellpine,
Carlton,
Chehulpum,
Hazelair,
Jory,
Linslaw,
Oakland,
Panther,
Steiwer,
Veneta,
Wellsdale,
Willakenzie, and
Windygap soils. Bellpine soils have hue redder than 7.5YR, are fine textured, 20 to 40 inches deep to a paralithic contact, have less
than 35 percent base saturation in the argillic horizon, and occur adjacent hills at higher elevations. Carlton soils are greater than 60 inches dep to bedrock, have a mollic epipedon, and occur on adjacent footslopes and terraces. Chehulpum soils are less than 20 inches deep to a paralithic contact, and occur on hills. Hazelair soils are very fine textured, lack an argillic horizon and occur on hills. Jory soils have hue redder than 7.5YR, are fine textured, greater than 60 inches deep to a paralithic contact, have less than 35 percent base saturation in the argillic horizon, and occur on adjacent hills at higher elevations. Linslaw soils have redox depletions with chroma of 2 or less at a depth of less than 30 inches, are somewhat poorly drained, and occur along drainageways dissecting old terraces and on colluvial fans. Oakland soils are well drained, 20 to 40 inches deep to a paralithic contact, and occur on foothills. Panther soils are poorly drained, very fine textured, and occur in swales and concave drainageways on hills. Steiwer soils are fine-loamy, 20 to 40 inches deep to a paralithic contact, have a mollic epipedon 10 to 20 inches thick, and occur on hills. Wellsdale soils are moderately well drained, 40 to 60 inches deep to a paralithic contact, and occur hills. Willakenzie soils are 20 to 40 inches deep to a paralithic contact, are well drained, and occur on hills. Windygap soils have hue redder than 7.5YR, are fine textured, 40 to 60 inches deep to a paralithic contact, have less than 35 percent base saturation in the argillic horizon, and occur on adjacent hills at higher elevations.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; moderately slow permeability. An apparent water table is at its uppermost limit from December to April.
USE AND VEGETATION: Most of these soils have been cleared and are used for Christmas trees, homesites, orchards, small grain, hay and pasture wildlife habitat and watersheds. Native vegetation consists of Oregon white oak, rose, poison-oak, grasses, and sedges.
DISTRIBUTION AND EXTENT: Low hills along the margins of the Willamette and Umpqua Valleys in Western Oregon; MLRA 2 and 5. The series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Benton County Area, Oregon, 1970.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from the soil surface to a depth of 24 inches (A1, A2, AB, and BA horizons).
Argillic horizon - the zone from 24 to 51 inches (Bt1, Bt2, and BCt horizons)
Aquultic feature - the zone from 34 to 42 inches having redox depletions with chroma of 2 or less and the zone from24 to 42 inches having base saturation (sum) of less than 75 percent
Particle-size control section - the zone from 24 to 44 inches (Bt1, Bt2 and upper 2 inches of the BCt horizon)
The typical pedon was relocated based on field documentation from the MLRA A2 Willamette Valley update project. The pedon reflects a modal series concept which includes: very deep to bedrock, somewhat poorly drained, brown hues, superactive cation exchange activity class, medium to moderately fine textures in argillic horizon, and occuring dominantly on the Eugene, Fisher, and Spencer geologic formations. The series occur along the margins of the Willamette Valley. It is differentiated from similar soils in fine families which occur on adjacent geologic formations which are derived from siltstone, have red hues, and an active cation exchange activity class. The Dupee series occur on the Dolph geomorphic surface.