LOCATION SAN TIMOTEO CAEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, calcareous, thermic Typic Xerorthents
TYPICAL PEDON: San Timoteo loam - range. (Colors are for dry soil unless otherwise stated.)
0i--1/8 to 0 inch; dark brown litter from low shrubs, partially decomposed.
A1--0 to 9 inches; pale brown (10YR 6/3) loam, brown (10YR 5/3) moist; weak fine granular structure; soft, friable, nonsticky and slightly plastic; many fine and medium roots; violently effervescent; moderately alkaline (pH 8.2); clear smooth boundary. (8 to 12 inches thick)
A2--9 to 14 inches; light gray (10YR 7/2) loam, pale brown (10YR 6/3) moist; massive; soft, friable, nonsticky and slightly plastic; few medium and coarse roots; violently effervescent; moderately alkaline (pH 8.2); gradual smooth boundary. (5 to 8 inches thick)
C--14 to 22 inches; light gray (10YR 7/2) loam, grayish brown (10YR 5/2) moist; massive; soft, friable, nonsticky and slightly plastic; few medium and coarse roots; violently effervescent; moderately alkaline (pH 8.2); clear irregular boundary. (5 to 8 inches thick)
Cr--22 to 28 inches; light gray (10YR 7/2) decomposing soft sandstone that can be broken down to sandy loam, pale brown (10YR 6/3) moist; violently effervescent; moderately alkaline (pH 8.2).
TYPE LOCATION: Riverside County, California; about 5 miles north of Moreno, California; approximately 150 feet SW of intersection of Redlands Blvd. and San Timoteo Canyon Road, 900 feet north and 500 feet east of SW corner sec. 13, T. 2 S., R. 3 W., SBBM.
RANGE IN CHARACTERISTICS: Depth to a paralithic contact is typically 20 to 40 inches, but is only 20 to 30 inches in many pedons. The mean annual soil temperature is 59 to 65 degrees F and rarely, if ever, is the soil temperature below 47 degrees F. The soil between depths of about 8 to 25 inches usually is dry in all parts from about April until late November or mid-December, and usually is moist in some or all parts all the rest of the year. Textures are sandy loam, fine sandy loam, loam or silt loam and have less than 18 percent clay. The soils are slightly to violently effervescent throughout, but have less carbonates in the upper parts. Some pedons do not have carbonates in the upper parts. Carbonates are generally disseminated with few, if any, segregations other than in the underlying soft sandstone material. It is slightly or moderately alkaline.
The A horizon has dry color of 10YR 5/2, 5/3, 6/1, 6/2, 6/3, 6/4, 7/1, 7/2; 2.5Y 5/2, 6/4, 7/2. Moist colors are 10YR 4/2, 4/3, 4/4, 5/3, 5/4 and 6/3. It has less than 1 percent organic matter in the upper 7 inches of soil.
The C horizon has dry color of 10YR 5/3, 5/4, 6/1, 6/2, 6/3, 6/4, 7/1, 7/2, 7/3 and 7/4; 2.5Y 6/2, 6/4 and 7/2. Moist colors are 10YR 4/3, 4/4, 4/6, 5/2, 5/3, 5/4, 5/6 and 6/3.
COMPETING SERIES: This is the Padres (T) series. Balcom, Castaic, Cieneba, Garretson, Pollasky, San Emigdio, Saugus, Shedd and Trigo series are similar soils in other families. Balcom and Castaic soils have more than 18 percent clay. Cieneba and Trigo soils have a paralithic contact less than 20 inches below the surface. Garretson soils lack a paralithic contact and have more than 18 percent clay. Pollasky and Saugus soils are noncalcareous. San Emigdio soils are stratified, have an irregular decrease in organic matter and lack a paralithic contact. Shedd soils are fine-silty and have a chroma of less than 2.
GEOGRAPHIC SETTING: San Timoteo soils have 2 to 75 percent slopes and are on uplands at elevations of 300 to 3,500 feet. They formed in material weathered from shale, sandstone and calcified weathered granite. The climate is subhumid with warm dry summers and cool moist winters. Annual precipitation (rainfall) is 9 to 20 inches. The average January temperature is about 50 degrees F, average July temperature is about 75 degrees F, and the average annual temperature is 60 to 65 degrees F. The frost-free season is 240 to 310 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the similar Cieneba and San Emigdio soils and the Metz and Vista soils. Metz soils are sandy and lack a paralithic contact. Vista soils are not calcareous.
DRAINAGE AND PERMEABILITY: Well to somewhat excessively drained; very low to medium runoff; moderately rapid permeability.
USE AND VEGETATION: The soils are used mostly for grazing or watershed except for small cultivated areas. Vegetation is mostly California sagebrush, flattop buckwheat, yucca, sugarbush and annual grasses.
DISTRIBUTION AND EXTENT: Central Coast Range and southern California. They are moderately extensive in MLRA-15, 20.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Monterey County, California 1972.
REMARKS: The San Timoteo soils were formerly classified as Regosols.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from the surface to 14 inches (A1,A2)
Calcareous reaction class - the fine earth fraction effervesces in all parts below 10 inches.
CEC/Clay ratio estimated from similar soils with laboratory data in the W. Stanislaus Soil Survey Area.