LOCATION DUART OR
Established Series
Rev. TAD/AON
01/2023
DUART SERIES
The Duart series consists of moderately deep, well drained soils that formed in reworked loess and ash. These soils are on uplands and have slopes of 1 to 55 percent. The mean annual precipitation is about 13 inches and the mean annual air temperature is about 49 degrees F.
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Typic Haploxerolls
TYPICAL PEDON: Duart silt loam, cultivated. (Colors are for moist soil unless otherwise noted.)
Ap--0 to 8 inches; very dark grayish brown (10YR 3/2) silt loam, grayish brown (10YR 5/2) dry; weak fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; many very fine irregular pores; 3 percent rock fragments, 2 mm. to 1 inch in diameter; neutral (pH 6.6); abrupt smooth boundary. (5 to 8 inches thick)
A--8 to 16 inches; very dark grayish brown (10YR 3/2) silt loam, grayish brown (10YR 5/2) dry; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; many very fine tubular pores;3 percent rock fragments 2 mm. to 1 inch in diameter; neutral (pH 6.7); clear smooth boundary. (0 to 10 inches thick)
Bw1--16 to 26 inches, dark brown (10YR 3/3) silt loam, brown (10YR 5/3) dry; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; many very fine tubular pores; about 2 percent rock fragments, 2 mm. to 1 inch in diameter; 5 percent very hard noncalcareous nodules, 1/2 to 1 inch in diameter; neutral (pH 6.8); clear smooth boundary. (6 to 15 inches thick)
Bw2--26 to 33 inches; dark brown (10YR 3/3) silt loam, pale brown (10YR 6/3) dry; weak medium to fine subangular blocky structure; hard, firm, slightly sticky and slightly plastic; common very fine roots; many very fine tubular pores; about 2 percent rock fragments 2 mm. to 1 inch in diameter; 5 percent very hard noncalcareous nodules 1/2 to 1 inch in diameter; neutral (pH 6.8); clear wavy boundary. (5 to 12 inches thick)
2Crk--33 to 39 inches; dark brown (10YR 3/3) semiconsolidated sandstone, pale brown (10YR 6/3) dry; extremely hard, extremely firm; few mycelia strands of lime.
TYPE LOCATION: Wasco County, Oregon; 190 feet north of road in NW1/4 NW1/4 SW1/4 sec. 31, T.1N., R.14E.
RANGE IN CHARACTERISTICS: In most years, the soils are usually moist but are dry for more than 80 to 90 consecutive days between depths of 4 and 12 inches within the 4 month period following the summer solstice. The mean annual soil temperature is 50 to 52 degrees F. Depth to a paralithic contact is 20 to 40 inches. The solum is 20 to 40 inches thick. Organic matter decreases to less than 1 percent above depth of 20 inches and commonly between depths of 10 and 15 inches. The mollic epipedon is 10 to 20 inches thick. Rock fragments up to about 1 inch in diameter range up to 3 percent in the solum.
The B horizon has value of 5 or 6 dry and 3 or 4 moist. It is silt loam or loam with 16 to 18 percent clay and more than 15 percent fragments coarser than very fine sand. This horizon has weak medium to fine subangular blocky structure. It has up to 5 percent noncalcareous nodules 1/2 to 1 inch in diameter.
COMPETING SERIES: These are the
Anders,
Beckley,
Battleplain,
Chenoweth,
Cleverly,
Conconully,
Hesslan, Juliaetta,
Knutsen,
Laidlaw, Newborn,
Owhi,
Phoebe,
Uhlig, and
Wato series. Anders soils have a lithic contact at depths of 20 to 40 inches. Beckley, Battleplain, Chenoweth, Cleverly, Conconully, Juliaetta, Knutsen, Laidlaw, Newborn, Owhi, Phoebe, Uhlig, and Wato soils lack a paralithic or lithic contact above depth of 40 inches. Also, Beckley, Battleplain, Conconully, Knutsen, Laidlaw, and Phoebe soils are moderately coarse textured. Cleverly, Hesslan and Knutsen soils have 5 to 35 percent rock fragments in their control section. Also, Hesslan soils dominantly are loam in the control section.
GEOGRAPHIC SETTING: Duart soils are on uplands and have nearly level to steep slopes. Dominant gradients are up to 25 percent but slopes range to 55 percent. Elevations range from 800 to 1,800 feet. The soils formed in a reworked loess mantle with an appreciable component of volcanic ash overlying semiconsolidated sandstone. Summers are warm and dry with an average July temperature of 68 degrees F. Winters are cool and moist with an average January temperature of 31 degrees F. The mean annual temperature is 48 degrees to 50 degrees F. Precipitation ranges from 12 to 14 inches annually. Frost-free period is 120 to 150 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Dufur, and
Walla Walla soils. Dufur soils are deeper than 40 inches to a paralithic contact. Walla Walla soils are 40 to more than 60 inches deep to bedrock and are coarse-silty.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; moderate permeability.
USE AND VEGETATION: Principal use is for grain crops. Other uses include hay and pasture and native range. Native vegetation is mainly bluebunch wheatgrass, Sandberg bluegrass, and forbs such as yarrow, phlox, buckwheat and balsamroot.
DISTRIBUTION AND EXTENT: North-central are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Wasco County, Oregon, 1975.
REMARKS: Diagnostic horizons and other features:
Mollic epipedon from 0 to 16 inches
Cambic horizon from 16 to 33 inches
National Cooperative Soil Survey
U.S.A.