LOCATION SAN SIMEON CAEstablished Series
TAXONOMIC CLASS: Fine, smectitic, thermic Xeric Argialbolls
TYPICAL PEDON: San Simeon sandy loam - brush covered rangeland. (Colors are for dry soil unless otherwise noted.)
02--2 inches to 0; decomposed leaves and grass.
A11--0 to 11 inches; grayish brown (10YR 5/2) sandy loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; slightly hard, very friable, nonsticky and nonplastic; many very fine and common fine roots; many very fine tubular and interstitial pores; medium acid (pH 6.0); clear smooth boundary. (10 to 15 inches thick)
A12--11 to 20 inches; brown (10YR 5/3) sandy loam, dark brown (7.5YR 3/2) moist; massive; slightly hard, friable, nonsticky and nonplastic; common very fine roots; many very fine tubular pores; medium acid (pH 6.0); clear smooth boundary. (0 to 10 inches thick)
A2--20 to 24 inches; light yellowish brown (10YR 6/4) sandy loam, dark brown (10YR 4/3) moist; few fine faint brown (7.5YR 5/4) mottles; massive; slightly hard, friable, nonsticky and nonplastic; common very fine roots; many very fine tubular pores; very few thin clay films bridging sand grains; medium acid (pH 6.0); abrupt smooth boundary. (3 to 6 inches thick)
B2t--24 to 34 inches; brown and strong brown (7.5YR 5/4 and 5/6) clay, mixed dark brown and strong brown (7.5YR 4/4 and 5/6) moist, brown and dark brown (7.5YR 5/2 and 4/2) films and dark red (2.5YR 3/6) spots; dark brown (7.5YR 4/2 and 3/2) films and dark red (2.5YR 3/6) spots moist; moderate fine prismatic structure; very hard, firm, sticky and plastic; few fine roots; common very fine tubular pores; many moderately thick clay films on faces of peds and lining pores; very strongly acid (pH 4.8); clear wavy boundary. (10 to 27 inches thick)
Cr--34 inches; reddish yellow (7.5YR 6/6) sandstone that crushes to sandy clay loam, yellowish red (5YR 5/6) moist; massive; few thick clay films lining pores; very strongly acid (pH 4.8).
TYPE LOCATION: San Luis Obispo County, California on Hearst Ranch about 3,700 feet north and 5,900 feet east of Point Piedras Blancas lighthouse, T. 26 S. R. 6 E., MDB&M.
RANGE IN CHARACTERISTICS: Depth to a paralithic contact of soft sandstone is 20 to 40 inches. The mean annual soil temperature is about 61 degrees F. The soil between depths of 10 to 29 inches is usually dry all of the time from mid-July until November and is moist in some part the rest of the year.
The A1 horizon is gray, grayish brown or brown (10YR 5/1, 5/2, 5/3; 7.5YR 5/2) dry, and very dark grayish brown or dark brown (10YR 3/2, 3/3; 7.5YR 3/2) moist. It is sandy loam or loam and has 10 to 20 percent clay and is medium or slightly acid
The A2 horizon is light gray, gray, light yellowish brown or light brownish gray (10YR 7/1, 6/1, 6/2, 6/4) or grayish brown (2.5Y 5/2) with few or common, fine and distinct mottles of pale brown, light yellowish brown or brown (10YR 6/3, 6/4; 7.5YR 5/4). It is sandy loam or loam and has 5 to 15 percent clay. Reaction is medium acid to very strongly acid.
Typically, the B2t horizon appears marbled with polychromatic colors of brown or strong brown (7.5YR 5/4, 5/6), dark grayish brown, grayish brown and yellowish brown (10YR 4/2, 5/2, 5/4), or light yellowish brown (2.5Y 6/2) with spots, streaks, patches and films of dark red or red (2.5YR 3/6, 4/6), reddish brown (5YR 4/4), brown or strong brown (7.5YR 4/2, 5/2, 5/4, 5/6), yellowish brown or dark grayish brown (10YR 5/4, 5/8, 4/2). It is clay with 45 to 60 percent clay. It is very strongly acid to medium acid. Base saturation is 55 to 85 percent. Some pedons have a few non-intersecting slickensides.
The Cr layer of soft sandstone is polychromatic and often appears marbled with streaks, spots and films in hues ranging from 7.5YR to 5Y. This material crushes to textures ranging from sandy loam to sandy clay, depending upon the amount of clay films in cracks. Reaction is very strongly acid to medium acid.
COMPETING SERIES: These are the Concepcion and Watsonville series. Both of these soils lack a paralithic contact to sandstone.
GEOGRAPHIC SETTING: San Simeon soils are on hills and have slopes of 2 to 50 percent. The soils formed on sandstone. Elevations are from near sea level to 500 feet. The climate is subhumid mesothermal with warm dry summers and moist cool winters. Mean annual precipitation is 18 to 25 inches. Average January temperature is about 52 degrees F.; average July temperature is about 55 degrees F.; mean annual temperature is about 55 degrees F. The frost-free season is 330 to 365 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Concepcion soils and the Los Osos soils. Los Osos soils have a gradual A/B horizon boundary.
DRAINAGE AND PERMEABILITY: Moderately well drained; slow to rapid runoff; very slow permeability.
USE AND VEGETATION: Used for range, watershed and wildlife. Native vegetation is annual grasses and forbs in some areas. In other areas, it is thick stands of coyote bush, low manzanita, scrub oak and bunchgrass.
DISTRIBUTION AND EXTENT: Area within 2 miles of the coast along the north coast of San Luis obispo County. These soils are inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: San Luis Obispo County, California, Coastal Part, 1977.
REMARKS: Base saturation data are from California Polytechnic State University, San Luis Obispo, and are not published.
OSED scanned by SSQA. Last revised by state on 11/77.