LOCATION BASHAW OREstablished Series
TAXONOMIC CLASS: Very-fine, smectitic, mesic Xeric Endoaquerts
TYPICAL PEDON: Bashaw clay, native pasture (Colors are for moist soil unless otherwise noted.)
A--0 to 3 inches; very dark gray (10YR 3/1) clay, dark gray (10YR 4/1) dry; moderate medium and fine subangular blocky structure; very hard, firm, very sticky and very plastic; common very fine roots; many very fine pores; many fine distinct yellowish red (5YR 4/6) masses of iron accumulation; moderately acid (pH 5.8); abrupt smooth boundary. (3 to 10 inches thick)
Bssg1--3 to 14 inches; black (N 2/ ) clay, very dark gray (N 3/ ) dry; appears massive when wet, but weak coarse prismatic and weak coarse angular blocky structure when moist or dry; very firm, very hard, very sticky and very plastic; common very fine roots; many very fine pores; few fine distinct yellowish red (5YR 5/6) masses of iron accumulation; common fine dark yellowish brown (10YR 4/6) and black (10YR 2/1) concretions; few slickensides moderately acid (pH 6.0); clear smooth boundary. (6 to 35 inches)
Bssg2--14 to 31 inches; black (N 2/ ) clay, very dark gray (N 3/ ) dry; massive; very hard, very firm, very plastic and very sticky; few very fine roots; few very fine pores; few fine prominent yellowish red (5YR 4/6) masses of iron accumulation; common fine dark yellowish brown (10YR 4/6) and black (10YR 2/1) concretions; few slickensides; neutral (pH 6.6); gradual smooth boundary. (0 to 20 inches thick)
Bssg3--31 to 48 inches; very dark gray (N 3/ ) clay, dark gray (N 4/ ) dry; massive; very hard, very firm, very sticky and very plastic; common fine gray colored weathered coarse fragments; few roots; few very fine pores; common medium distinct light olive brown (2.5Y 5/6) masses of iron accumulation; common intersecting slickensides; neutral (pH 7.0); abrupt smooth boundary. (0 to 20 inches thick)
Cg--48 to 60 inches; dark grayish brown (2.5Y 4/2) clay, light brownish gray (2.5Y 6/2) dry; massive; very hard, firm, moderately sticky and moderately plastic; common very fine pores; many medium distinct dark brown (7.5YR 3/2) and dark reddish brown (5YR 3/2) masses of iron accumulation; and few medium faint dark gray (N 4/ ) iron depletions; neutral (pH 7.0).
TYPE LOCATION: Marion County, Oregon. In a native pasture about 2300 feet east and 1,500 feet south of the NW corner of section 9, T. 6 S., R. 1 W.; Willamette Meridian. Silverton, Oregon USGS 7.5 minute topographic quadrangle. Latitude 45 degrees, 04 minutes, 04 seconds N. and Longitude 122 degrees, 48 minutes, 57 seconds W.; NAD 27.
RANGE IN CHARACTERISTICS: These soils are usually moist and are saturated with water for several months each year. The mean annual soil temperature ranges from 50 to 57 degrees F. The soils crack and open and close once each year and remain open for 60 consecutive days or more in most years. The soil is dry for 45 to 60 consecutive days following the summer solstice within MLRA 2 but ranges to 90 days within MLRA 5. The profiles to 40 inches or more have chroma of 1 or less and have faint to prominent redox concentrations throughout. Hue is 10YR, 2.5Y, 5Y and neutral and are commonly neutral below the A horizon. The particle-size control section has 60 percent or more clay. Slickensides are close enough to intersect in all or in some part between 10 to 40 inches.
The A horizon typically has value of 2 moist but may range to 3 in the upper 3 inches, 3 or 4 dry and chroma of 1 or less. Texture is clay, silty clay, or silty clay loam with 35 to 70 percent clay. It has weak to strong granular or very fine subangular blocky structure. Soil reaction is strongly acid or moderately acid.
The Bssg horizon has value of 2 moist and 3 or 4 dry above 30 inches; below 30 inches, value ranges to 4 moist and 3 to 6 dry. Chroma is 1 or less above 40 inches and ranges to 2 below 40 inches. It has 55 to 70 percent clay and 0 to 3 percent gravel. Slickensides are few to common and intersecting. The structure when moist or dry is weak coarse prismatic to coarse angular blocky and wedge-shaped; when wet, this horizon appears structureless. Soil reaction is moderately acid to neutral.
The Cg horizon has similar range in colors as the horizons above except that the chroma ranges to 2. Texture is clay, silty clay, or sandy clay. It has 45 to 70 percent clay and 0 to 5 percent gravel. Soil reaction is slightly acid to slightly alkaline.
COMPETING SERIES: These are the Coker, Natroy, and Padigan series. Coker soils are moderately alkaline below 20 inches and are dry for 80 to 110 consecutive days following the summer solstice. Natroy soils have moist chroma of 2 within the upper 12 inches of the solum, moist chroma of 1 to 3 in the lower part of the solum, and lack neutral hues in the B horizon. Padigan soils are moderately alkaline to strongly alkaline in the particle-size control section and have carbonates beginning at a depth of 20 inches.
GEOGRAPHIC SETTING: The Bashaw soils are on nearly level or slightly concave flood plains and terraces and gently sloping alluvial fans. Elevations are 90 to 1,000 feet. Slopes are 0 to 12 percent. The soils formed in clayey alluvium derived dominantly from basic igneous rock. The climate is characterized by warm, wet winters and hot, dry summers. The mean annual precipitation is 30 to 60 inches and occurs moistly as rain during the last fall, winter and spring. The average July temperature is 67 degrees F. and average January temperature is 39 degrees F., the mean annual temperature is 50 to 55 degrees F. The frost-free period is 160 to 235 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cove, Waldo, Wapato and Witham soils. All of these soils lack intersecting slickensides. In addition, Wapato soils are moderately fine textured with less than 35 percent clay and the Witham soils are somewhat poorly drained. Cove soils are on flood plains and terraces in areas that alluvium is from mixed sources. Waldo and Wapato soils are on flood plains adjacent to the river or stream. Witham soils are on fans, foot slopes, and toe slopes.
DRAINAGE AND PERMEABILITY: Poorly drained; very slow permeability. An apparent water table is at its uppermost limit from November to May and is ponded from December to April. Where this soil occurs on flood plains, occasional or frequent flooding for long periods occurs from December to April unless protected.
USE AND VEGETATION: These soils are used for pasture and for growing spring grains. Natural vegetation is sedges, rushes, grasses, scattered ash, willows and other trees and shrubs.
DISTRIBUTION AND EXTENT: Willamette Valley in western Oregon; MLRA 2, 5. The soils occur in small bodies and are inextensive.
MLRA OFFICE RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Benton County (Benton Area), Oregon, 1970.
REMARKS: Diagnostic features recognized in this pedon:
Aquerts feature - the zone from 0 to 48 inches having aquic conditions for sometime in most years and chroma of 1 or less with redox concentrations.
Endosaturation - the zone from 0 to 60 inches is saturated with water for some period of time.
The classification was changed from Typic Pelloxererts to Xeric Endoaquerts in 5/94.
ADDITIONAL DATA: Characterization data is available for sample #S99OR-043-001, S96OR-043-003, and S92OR-003-004 NSSL, Lincoln, NE, 12/01.