LOCATION SEVILLE CAEstablished Series
TAXONOMIC CLASS: Fine, smectitic, thermic Aridic Durixererts
TYPICAL PEDON: Seville clay, barley. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 9 inches; brown (7.5YR 4/2) clay, dark brown (7.5YR 3/2) moist; strong medium and coarse angular blocky structure; extremely hard, very firm, very sticky and very plastic; many very fine roots; many very fine pores; slightly alkaline (pH 7.8); clear smooth boundary. (4 to 10 inches thick)
Bss--9 to 25 inches; dark reddish gray (5YR 4/2) clay, dark reddish brown (5YR 3/2) moist; moderate medium and fine angular blocky structure; extremely hard, very firm, very sticky and very plastic; common very fine roots; common very fine pores; many slickensides; slightly effervescent, carbonates disseminated; moderately alkaline (pH 8.0); clear smooth boundary. (8 to 20 inches thick)
Bk--25 to 38 inches; reddish brown (5YR 4/3) clay, dark reddish brown (5YR 3/3) moist; massive; extremely hard, very firm, very sticky and very plastic; violently effervescent, carbonates disseminated and segregated as common fine and medium soft masses; strongly alkaline (pH 8.5); abrupt wavy boundary. (4 to 14 inches thick)
2Bqkm--38 to 52 inches; light reddish brown (5YR 6/3) duripan; top 12 inches is strongly cemented and becomes less cemented with depth; violently effervescent, carbonates segregated as common filaments and soft masses in seams and fractures; abrupt wavy boundary. (4 to 20 inches thick.)
2Bqk--52 to 62 inches; reddish brown (5YR 5/4) sandy clay loam, reddish brown (5YR 4/4) moist; massive; hard, friable, sticky and slightly plastic; 10 percent discontinuous weak silica cementation; slightly effervescent, carbonates disseminated and violently effervescent, carbonates segregated as common fine and medium soft masses; moderately alkaline (pH 8.0).
TYPE LOCATION: Tulare County, California; about 1/2 mile south of Seville, California; 83 feet east of Road 156 and 1,900 feet north of Avenue 376; NW1/4 SW1/4 section 1, T.17 S., R.25 E., Ivanhoe Quadrangle; MDB&M.
RANGE IN CHARACTERISTICS: Depth to the duripan is 20 to 40 inches. The mean annual soil temperature is 60 to 65 degrees F. The soil between depths of 4 to 12 inches is usually dry all of the time from about May 15 to November 15 or early December and is moist in some part or all parts all the rest of the year. The soil has cracks 1 cm or more wide that extend from the surface to a depth of 20 inches or more when dry. Clay content is 40 to 60 percent from the soil surface to the duripan.
The A horizon is 7.5YR 5/2 or 5/4, 5YR 4/2, 4/3, 4/4, 5/3 or 5/4 and is commonly 2 units of value darker when moist. This horizon is neutral, slightly alkaline or moderately alkaline. Some pedons are slightly or strongly effervescent. Carbonates occur as mycelia, soft masses or concretions but is disseminated in some pedons.
The B horizon is 5YR 3/2, 3/3, 3/4, 4/2, 4/3, 4/4, 5/3, or 5/4, 2.5YR 3/4, 4/4, or 5/4 and is commonly two units of value darker when moist. Some pedons have few to many, thin to moderately thick clay films. This horizon is noneffervescent to violently effervescent. Reaction is neutral to strongly alkaline.
The 2Bqkm horizon is 5YR 4/3, 4/4, 5/3, 5/4, 6/2, 6/3, 6/4, or 7/2, 7.5YR 6/2 or 7/2, or 10YR 6/2 and is commonly two units of value darker when moist. It is weakly or strongly cemented, but is not indurated in any layer. Carbonates occur in seams, fractures or on top of the duripan. 2Btqk and 2Btkqm horizons may be present with characteristics similar to the 2Bqkm.
The substratum below the duripan is absent in some pedons. Where present it ranges from loamy coarse sand with 3 percent clay to a sandy clay loam with 30 percent clay.
COMPETING SERIES: Competing series not reviewed at this time.
GEOGRAPHIC SETTING: Seville soils are on alluvial fans, stream terraces and valley fill at elevations of 300 to 500 feet. Slopes range from 0 to 2 percent. The soils formed in alluvium mainly from basic igneous sources. The climate is dry subhumid mesothermal with hot, dry summers and cool, moist winters. The mean annual precipitation is 10 to 15 inches. The mean January temperature is 46 degrees F.; the mean July temperature is 80 degrees F.; and the mean annual temperature is 62 to 65 degrees F. The frost free season is 250 to 300 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Exeter soils. Exeter soils have a fine-loamy particle-size control section.
DRAINAGE AND PERMEABILITY: Moderately well drained; medium or high runoff; slow permeability above the duripan, very slow in the duripan, and moderately rapid below the duripan.
USE AND VEGETATION: Irrigated cropland, commonly oranges, olives, tomatoes, stone fruits, table grapes, barley, and cotton lint. Native vegetation in non-farmed areas is mainly annual grasses and forbs.
DISTRIBUTION AND EXTENT: Eastern side of San Joaquin Valley. The soils are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.
SERIES ESTABLISHED: Visalia Area, Tulare County, California, 1935.
REMARKS: Competing series not reviewed at this time 9/95