LOCATION BANCAS CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, active, mesic Mollic Haploxeralfs
TYPICAL PEDON: Bancas stony loam - chaparral shrub. (Colors are for dry soil unless otherwise stated).
01--0.25 to 0 inches; chaparral leaf litter.
A11--0 to 2 inches; brown (7.5YR 5/2) stony loam, dark brown (7.5YR 3/2) moist; weak fine granular structure; slightly hard, friable, slightly sticky, slightly plastic; many very fine and few fine roots; many very fine interstitial and common fine tubular pores; neutral (pH 7.0); clear smooth boundary. (2 to 3 inches thick)
A12--2 to 5 inches; brown (7.5YR 5/2) loam, dark brown (7.5YR 3/2) moist; weak fine granular structure; hard, friable, slightly sticky, slightly plastic; many very fine and few fine roots; many very fine interstitial and common fine tubular pores; neutral (pH 7.0); abrupt smooth boundary. (2 to 4 inches thick)
B21t--5 to 12 inches; yellowish red (5YR 4/6) clay loam, dark red (2.5YR 3/6) moist; strong fine angular blocky structure; extremely hard, firm, sticky, plastic; few fine and medium roots; common very fine and fine tubular pores; many moderately thick clay films line pores and on faces of peds; slightly acid (pH 6.5); clear smooth boundary. (4 to 9 inches thick)
B22t--12 to 22 inches; yellowish red (5YR 5/6) clay loam, yellowish red (5YR 4/6) moist; strong medium subangular blocky structure; extremely hard, firm, sticky, plastic; few fine and medium roots; common very fine and fine tubular pores; many moderately thick clay films line pores, common moderately thick films on films on faces of peds; slightly acid (pH 6.5); clear smooth boundary. (8 to 16 inches thick)
B3t--22 to 27 inches; strong brown (7.5YR 5/6) light clay loam, yellowish red (5YR 4/6) moist; moderate medium subangular blocky structure; extremely hard, firm, sticky, plastic; few fine and medium roots; common very fine and fine tubular pores; few thin to moderately thick clay films on faces of peds; slightly acid (pH 6.5); clear smooth boundary. (2 to 10 inches thick)
C--27 to 36 inches; varicolored strong brown (7.5YR 5/8) and brownish yellow (10YR 6/6) weathered rock, strong brown (7.5YR 5/6) and yellowish brown (10YR 5/6) moist; massive; very hard, firm, slightly sticky, slightly plastic; few medium roots; common fine and tubular pores; few thin clay films line pores and bridge sand grains; after crushing and rubbing feels like gritty loam, slightly acid (pH 6.5).
TYPE LOCATION: San Diego County, California; about 3 miles south of Descanso on the Las Bancas Road in the SE 1/4 NW 1/4 section 6, T. 16 S., R. 4 E.
RANGE IN CHARACTERISTICS: Depth to a paralithic contact of weathered rock is 20 to 40 inches. The mean annual soil temperature at a depth of 20 inches is about 57 to 59 degrees F and the soil temperature is not below 47 degrees F after about the 10th of February. Soil between the depths of about 5 and 15 inches usually is moist in some or all parts from about December 1 until late May and usually is dry all the rest of the time. Rock fragments usually make up less than 5 percent of the soil except in some pedons there is more than 5 percent rock fragments in and near the surface and near the paralithic contact.
The A horizon is brown to dark brown (10YR 5/3, 4/3; 7.5YR 5/2, 5/4, 4/2, 4/4) dry and has a moist value of 3. Organic matter averages 1 to 3 percent in the upper 4 to 5 inches and is less than 1 percent below a depth of 7 to 8 inches. This horizon is fine sandy loam or loam and is neutral or slightly acid.
The B2t horizon is strong brown or yellowish red or it is red in 2.5YR hue. This horizon is clay loam or sandy clay generally with less than 30 percent clay. It is slightly or moderately acid.
COMPETING SERIES: These are the Blakeport, Bull Trail, Morical, and Steinbeck series. Blakeport soils are medium to strongly acid throughout and are dry for only 60 to 80 days. Bull Trail and Steinbeck soils lack a paralithic contact within 40 inches of the surface. Morical soils are neutral or slightly alkaline in the B horizon and have a chroma of 4 or less in the B horizon.
GEOGRAPHIC SETTING: Bancas soils are on rolling to very steep uplands at elevations of 5,000 feet down to 2,000 feet on north slopes. They formed in residuum weathered from rock, usually somewhat metamorphosed but including granite, gneiss, quartz diorite, and quartz mica schist. The mean annual precipitation is 18 to 30 inches. The average January temperature is 42 degrees F, the average July temperature is 68 degrees F, and the mean annual temperature is 56 to 58 degrees F. The frost-free season is 175 to 230 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Holland, La Posta and Sheephead soils. Holland soils have less than 75 percent base saturation and lack a paralithic contact above a depth of 40 inches. La Posta soils have a mollic epipedon and are sandy. Sheephead soils have a mollic epipedon and have a paralithic contact less than 20 inches below the surface.
DRAINAGE AND PERMEABILITY: Well-drained; medium to very rapid runoff; moderate permeability.
USE AND VEGETATION: Used for range, wildlife, and watershed. The native vegetation is chaparral, and is mainly chamise, eastwood manzanita, cutleaf ceanothus, and scrub oak.
DISTRIBUTION AND EXTENT: Mainly in the mountains of southern California. The soil is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: San Diego County, California, 1973.
REMARKS: The Bancas soils were formerly classified as (medial) Noncalcic Brown soils.
The activity class was added to the classification in January of 2003. Competing series were not checked at that time. - ET
Last revised by the state on 8/73.