LOCATION SITTON OREstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, active, mesic Ultic Haploxeralfs
TYPICAL PEDON: Sitton loam-on a 55 percent linear-concave south-facing slope that is timbered at an elevation of 541 feet. (Colors are for moist soil unless otherwise noted)
A1--0 to 4 inches; dark brown (7.5YR 3/2) loam, brown (7.5YR 4/3) dry; strong medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine and common fine, medium, coarse, and very coarse roots; many very fine irregular and common fine, medium, coarse, and very coarse tubular pores; moderately acid (pH 5.7); abrupt smooth boundary. (2 to 6 inches thick)
A2--4 to 11 inches; dark brown (7.5YR 3/4) loam, brown (7.5YR 5/4) dry; moderate fine subangular blocky structure; moderately hard, friable, slightly sticky and slightly plastic; many very fine and common fine, medium, coarse, and very coarse roots; many very fine and common fine, medium, coarse, and very coarse tubular pores; strongly acid. (pH 5.5); clear wavy boundary. (4 to 8 inches thick)
BAt--11 to 16 inches; brown (7.5YR 4/4) loam, brown (7.5YR 5/4) dry; moderate medium and coarse subangular blocky structure; moderately hard, firm, slightly sticky and moderately plastic; common very fine, medium, coarse, and very coarse and few fine roots; many very fine and common fine, medium, coarse, and very coarse tubular pores; few faint clay films on faces of peds and along surfaces of pores; strongly acid. (pH 5.3); gradual wavy boundary. (0 to 8 inches thick)
Bt1--16 to 27 inches; brown (7.5YR 4/4) clay loam, strong brown (7.5YR 5/6) dry; moderate medium and coarse subangular blocky structure; hard, firm, slightly sticky and moderately plastic; common very fine, medium, coarse, and very coarse and few fine roots; many very fine and common fine, medium, coarse, and very coarse tubular pores; common distinct clay films on faces of peds and along surfaces of pores; strongly acid. (pH 5.2); gradual wavy boundary. (10 to 25 inches thick)
Bt2--27 to 37 inches; brown (7.5YR 4/4) loam, strong brown (7.5YR 5/6) dry; weak medium and coarse subangular blocky structure; hard, firm, slightly sticky and moderately plastic; common very fine, medium, coarse, and very coarse and few fine roots; many very fine and common fine, medium, coarse, and very coarse tubular pores; common distinct clay films on faces of peds and along surfaces of pores; 2 percent angular weakly cemented sandstone paragravel; strongly acid. (pH 5.3); gradual wavy boundary. (9 to 30 inches thick)
BCt1--37 to 44 inches; strong brown (7.5YR 4/6) fine sandy loam, reddish yellow (7.5YR 6/6) dry; massive; hard, firm, slightly sticky and slightly plastic; common very fine and very coarse and few fine, medium, and coarse roots; many very fine, common fine and very coarse, and few medium and coarse tubular pores; common distinct clay films on faces of peds and along surfaces of pores; 5 percent angular weakly cemented sandstone paragravel; strongly acid. (pH 5.2); abrupt wavy boundary. (6 to 25 inches thick)
BCt2--44 to 60 inches; dark yellowish brown (10YR 4/6) fine sandy loam, brownish yellow (10YR 6/6) dry; massive; moderately hard, friable, nonsticky and nonplastic; common very fine and very coarse and few fine, medium, and coarse roots; common very fine and very coarse, and few fine, medium, and coarse tubular pores; few distinct clay films along surfaces of pores; 5 percent angular weakly cemented sandstone paragravel; strongly acid. (pH 5.1);.
TYPE LOCATION: Yamhill County, Oregon; 3 1/2 miles north of the town of Yamhill; SW1/4 NE1/4 SW1/4 of section 15, T. 2 S, R. 4 W. Willamette Meridian. (Latitude 45 degrees, 23 minutes, 43 seconds N. Longitude 123 degrees, 10 minutes, 13 seconds W. NAD 27) Gaston, Oregon USGS 7.5 minute topographic quadrangle.
RANGE IN CHARACTERISTICS: The mean annual soil temperature ranges from 52 to 55 degrees F. The soil is usually moist but is dry for 45 to 60 consecutive days in all parts between depths of 4 and 12 inches following the summer solstice. The particle-size control section has 27 to 35 percent clay and 30 to 50 percent sand, dominated by very fine and fine sand. It has 0 to 5 percent sandstone rock fragments. The pararock fragments are tuffaceous sandstone. Hue is 7.5YR or 10YR throughout.
The A1 horizon has value of 2 or 3 moist, 4 to 6 dry, and chroma of 2 or 3 moist and 2 to 4 dry. It is loam with 15 to 27 percent clay. Reaction is strongly acid or moderately acid.
The A2 horizon has value of 3 or 4 moist, 4 to 6 dry, and chroma of 2 to 4 moist and dry. It is loam with 17 to 27 percent clay. Reaction is strongly acid or moderately acid.
The BAt horizon, when present, has value of 3 or 4 moist, 4 to 6 dry, and chroma of 2 to 4 moist and dry. It is loam with 17 to 27 percent clay. Reaction is strongly acid or moderately acid.
The Bt1 horizon has value of 3 or 4 moist, 4 to 6 dry, and chroma of 3 or 4 moist and 4 to 6 dry. It is loam or clay loam with 25 to 35 percent clay. Reaction is strongly acid or moderately acid.
The Bt2 horizon has value of 4 moist, 4 to 6 dry, and chroma of 4 to 6 moist and dry. It is loam, clay loam, or sandy clay loam with 24 to 35 percent clay. It has 0 to 20 percent paragravel. Reaction is strongly acid or very strongly acid.
The BCt or C/Bt horizons have value of 4 or 5 moist, 4 to 7 dry, and chroma of 4 to 6 moist and 6 to 8 dry. It is loam, sandy clay loam, or fine sandy loam with 10 to 25 percent clay. It has 5 to 60 percent paragravel or discrete, intermingled bodies of C material. The amount is greater the closer this horizon is to the Cr horizon. It is strongly acid.
COMPETING SERIES: These are the Bigridge (T), Hospiter (T), Millerridge (T), Minniecreek (T), Speaker and Willakenzie soils.
Bigridge soils: 40 to 60 inches to metavolcanic bedrock (paralithic); dry for 120 consecutive days during the summer; particle-size control section has 5 to 35 percent rock fragments.
Hospiter soils: dry for more than 60 consecutive days during the summer; particle-size control section has 5 to 35 percent rock fragments.
Millerridge soils: 20 to 40 inches to ultramafic bedrock (lithic contact); dry for 120 consecutive days during the summer; particle-size control section has 15 to 35 percent rock fragments.
Minniecreek soils: 20 to 40 inches to metavolcanic bedrock (paralithic); dry for 120 consecutive days during the summer; particle-size control section has 2 to 35 percent rock fragments.
Speaker soils: 20 to 40 inches to metamorphic bedrock (paralithic); dry for 60 to 90 consecutive days during the summer; particle-size control section has 0 to 35 percent gravel and 0 to 5 percent cobbles.
Willakenzie soils: 20 to 40 inches deep to sandstone bedrock (paralithic).
GEOGRAPHIC SETTING: Sitton soils are on sideslopes of hills at elevations of 200 to 900 feet. Slopes range from 30 to 60 percent. The soils formed in colluvium from sandstone of the Spencer Formation. The climate is characterized by warm, wet winters and hot, dry summers. The mean annual precipitation is 40 to 50 inches. The average January temperature is 39 to 40 degrees F. and the average annual July temperature is 65 to 67 degrees F. The mean annual temperature is 50 to 54 degrees F. The frost-free period is 160 to 210 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dupee, Wellsdale (T), and Willakenzie soils. Dupee soils are fine textured, have iron depletions with chroma of 2 or less within 30 inches of the soil surface, and are on concave parts of the hillslope at slopes of less than 30 percent. Wellsdale soils have iron depletions with chroma of 2 or less within 30 inches of the soil surface and are on linear and concave parts of the hillslope at slopes of less than 30 percent. Willakenzie soils 20 to 40 inches to a paralithic contact and are on linear and convex parts of the hillslope.
DRAINAGE AND PERMEABILITY: Well drained; moderately slow permeability.
USE AND VEGETATION: Sitton soils are used for forestland, wildlife habitat, and recreation. Native vegetation includes Douglas fir, bigleaf maple, Oregon white oak, common snowberry, California hazel, Pacific poison oak, western swordfern, and grasses.
DISTRIBUTION AND EXTENT: Northwest Oregon. Sitton soils are on hills along the western margin of the Willamette Valley, Oregon. MLRA2. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Benton County, Oregon; 2004. The series exists as only a minor component in Benton County.
REMARKS: Diagnostic horizons and features recognized in this pedon include:
Ochric epipedon - the zone from a depth of 0 to 11 inches (A1 and A2 horizons)
Argillic horizon - the zone from a depth of 11 to 60 inches (BAt, Bt1, Bt2, BCt1, BCt2 horizons)
Particle-size control section - the zone from a depth of 11 to 31 inches (BAt, Bt1, and part of the Bt2 horizon) N
ADDITIONAL DATA: Characterization data from representative pedons with User Pedon ID #s 01OR071003 and 01OR071004.