LOCATION CONCEPCION CAEstablished Series
TAXONOMIC CLASS: Fine, smectitic, thermic Xeric Argialbolls
TYPICAL PEDON: Concepcion fine sandy loam, annual range, formerly cultivated. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 5 inches; grayish brown (10YR 5/2) fine sandy loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine interstitial pores; strongly acid (pH 5.2); clear wavy boundary. (4 to 7 inches thick)
A12--5 to 19 inches; grayish brown (10YR 5/2) fine sandy loam, very dark grayish brown (10YR 3/2) moist; massive; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and fine roots; many very fine interstitial and tubular pores; strongly acid (pH 5.2); abrupt smooth boundary. (2 to 13 inches thick)
A2--19 to 23 inches; light brownish gray (10YR 6/2) fine sandy loam, dark grayish brown (10YR 4/2) moist; massive; hard, very friable, slightly sticky and slightly plastic; common very fine and fine roots; many very fine interstitial and tubular pores; strongly acid (pH 5.2); abrupt smooth boundary. (2 to 13 inches thick)
B21t--23 to 30 inches; dark yellowish brown (10YR 4/4) and reddish brown (5YR 4/3) clay; dark yellowish brown (10YR 3/4) and dark reddish brown (5YR 3/3) moist; strong coarse prismatic structure; extremely hard, very firm, very sticky and very plastic; few very fine roots; few very fine tubular and common very fine interstitial pores; continuous thick clay films in pores; strongly acid (pH 5.2); abrupt smooth boundary. (2 to 13 inches thick)
B22t--30 to 37 inches; dark gray (10YR 4/1) and reddish brown (5YR 4/4) clay, very dark brown (10YR 2/2) and reddish brown (5YR 4/4) moist; moderate medium and coarse angular blocky structure; very hard, firm, very sticky and very plastic; few very fine and many thick clay films in pores; strongly acid (pH 5.5); gradual irregular boundary.
B3--37 to 64 inches; brownish gray (10YR 6/6) heavy clay loam, yellowish brown (10YR 5/6) moist; weak medium subangular blocky structure; hard, firm, sticky and plastic; few very fine roots; common very fine interstitial pores; many thick clay films on peds and common moderately thick clay films in pores; medium acid (pH 6.0).
TYPE LOCATION: Santa Barbara County, California; west of Gaviota State Beach and Hollister Ranch, 0.6 mile west of San Augustine Beach exit on Rancho Real, approximately 60 feet south of road.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 58 degrees to 60 degrees F. The mean summer soil temperature is about 67 degrees F., and the mean winter soil temperature is about 58 degrees F. Soil between depths of about 5 to 15 inches is usually moist in some part after the first of November until sometime in May and is dry all the rest of the year. The base saturation exceeds 50 percent in all parts.
The A1 horizon is grayish brown or dark grayish brown in 10YR hue. It is loamy sand, sandy loam, fine sandy loam or loam and has 1 to 3 percent organic matter. This horizon is strongly or medium acid and usually has weak granular or weak subangular blocky structure. Some cultivated pedons are massive.
The A2 horizon is light brownish gray, light gray, light grayish brown or very pale brown in 10YR hue. Small (1 to 5 mm) manganese concretions that make up 1 to 5 percent of the A2 horizon are present in the profiles with loamy sand textures. This horizon has the same texture as the A1 horizon. Organic matter is less than 1 percent. Some pedons have common distinct mottles in the A2 horizon.
The B2t horizon is mottled and has yellowish brown, dark yellowish brown, dark brown, brown, brownish yellow, pale brown, light brownish gray, dark grayish brown, dark reddish brown, dark gray or gray colors in 10YR or 5YR hue and reddish brown, dark reddish brown in 5YR or 2.5YR hue. It is clay, heavy clay loam or sandy clay. This horizon has medium or strong medium or coarse angular blocky structure in the lower part. It is typically strongly or medium acid but ranges to moderately alkaline in some pedons. The sodium absorption ratio is greater than 6.
COMPETING SERIES: These are the San Simeon and Watsonville series. San Simeon soils have a paralithic contact at depths of 20 to 40 inches. Watsonville soils have a sodium absorption ration of less than 6, are somewhat poorly drained and lack reddish mottles.
GEOGRAPHIC SETTING: Concepcion soils are on nearly level to steep terraces adjacent to and within 1 to 2 miles of the Pacific Ocean. Slopes are 0 to 50 percent. Elevation is 40 to 200 feet. The soils formed on weakly consolidated stratified alluvium or wind-deposited sandy material blown form nearby beaches. The climate is subhumid mesothermal with cool, rainless, but foggy summers, and cool moist winters. The mean annual precipitation is 15 to 24 inches. Average January temperature is 48 degrees to 52 degrees F., average July temperature is 63 degrees to 68 degrees F., and the average annual temperature is 56 degrees to 62 degrees F. The average frost-free season is 300 to 330 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Baywood, Botella, Diablo, Lopez, Milpitas, Positas, Santa Lucia and Tierra soils. Baywood soils are deep sandy soils. Botella soils have less than 35 percent clay in the argillic horizon and have 2 to 6 percent organic matter to depths greater than 20 inches. Diablo soils are clayey throughout. Lopez soils are shaly and have a lithic contact at depths of 6 to 20 inches. Milpitas, Positas and Tierra soils lack a mollic epipedon. Santa Lucia soils are shaly and have a lithic contact at depths of 20 to 40 inches.
DRAINAGE AND PERMEABILITY: Moderately well-drained; slow to very rapid runoff; very slow permeability.
USE AND VEGETATION: Used for grazing, production of dryfarm grain or hay and for urban areas.
DISTRIBUTION AND EXTENT: Areas within 2 miles of the coast along the south coast of Santa Barbara County. These soils are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Santa Barbara County, California, South Coastal Part, 1974.
REMARKS: The soils formed on alluvial terraces were formerly mapped Watsonville series. The soils formed on sandy wind deposits are similar in appearance to the Narlon series but are Mollisols rather than Ultisols.