LOCATION ACCELERATOR CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, active, thermic Typic Haploxeralfs
TYPICAL PEDON: Accelerator loam; on a southeast facing slope of 6 percent at 300 feet in elevation; south of Woodside, 2,000 feet west and 300 feet south of intersection of Sand Hill Road and Highway 280. (Colors are for dry soil unless otherwise noted. When described October 1, 1984, the soil was moist below 15 inches).
Ap--0 to 4 inches; light gray (10YR 7/1) loam with few fine distinct reticulate mottles of yellowish brown (10YR 5/6), dark grayish brown (10YR 4/2) and few fine distinct mottles of dark yellowish brown (10YR 4/4) moist; strong fine, medium, and coarse subangular blocky structure; hard, very friable, nonsticky and nonplastic; many very fine and fine roots; many very fine and fine tubular and interstitial and few coarse tubular pores; strongly acid (pH 5.5); abrupt, smooth boundary. (0 to 7 inches thick)
A1--4 to 13 inches; light brownish gray (10YR 6/2) loam, dark grayish brown (10YR 4/2) moist; weak fine and medium subangular blocky structure; hard, very friable, nonsticky and nonplastic; few very fine roots; many very fine and fine tubular and interstitial and few coarse tubular pores; medium acid (pH 6.0); diffuse, wavy boundary. (9 to 15 inches thick)
A2--13 to 19 inches; light brownish gray (10YR 6/2) loam, dark grayish brown (10YR 4/2) moist; weak fine and medium subangular blocky structure; hard, very friable, slightly sticky and slightly plastic; few very fine roots; many very fine tubular and interstitial and few coarse tubular pores; medium acid (pH 6.0); gradual, irregular boundary. (6 to 8 inches thick)
A3--19 to 23 inches; distinct mottles of brownish yellow (10YR 6/6 ), brown (10YR 5/3) moist; weak fine and medium subangular blocky structure; hard, very friable, nonsticky and nonplastic; few very fine roots; many very fine and fine tubular and interstitial pores; medium acid (pH 6.0); clear, irregular boundary (4 to 6 inches thick)
Bt1--23 to 29 inches; light gray (10YR 7/2) clay loam with common medium distinct reticulate mottles of yellow (10YR 7/6), grayish brown (2.5Y 5/2) moist; moderate fine, medium, and coarse subangular blocky and weak coarse prismatic structure; very hard, firm, sticky and plastic; few very fine roots; common very fine and fine tubular and interstitial pores; many moderately thick clay films on ped faces, in pores, and as bridges between mineral grains; medium acid (pH 6.0); diffuse, wavy boundary. (6 to 10 inches thick)
Bt2--29 to 41 inches; yellow (10YR 7/6) gravelly clay loam, grayish brown (2.5Y 5/2) moist; moderate fine, medium, and coarse subangular blocky structure; very hard, firm, sticky and plastic; common very fine and fine tubular and interstitial pores; 20 percent 2 to 10 mm pebbles; many moderately thick clay films on ped faces, in pores, and as bridges between mineral grains; strongly acid (pH 5.5); clear, irregular boundary. (10 to 14 inches thick)
Cr--41 to 45 inches; soft siltstone and sandstone.
TYPE LOCATION: San Mateo County, California; south of the town of Woodside at Sand Hill Christmas Tree Farm; 2,000 feet west and 300 feet south of intersection of Sand Hill Road and Highway 280; (Palo Alto 7.5' Quadrangle USGS. This area is not sectionalized)
RANGE IN CHARACTERISTICS: Depth to paralithic contact ranges from 40 to 60 inches. Reaction is strongly acid to medium acid. The mean annual soil temperature ranges from 60 to 62 degrees F. The soil between the depth of 4 to 12 inches is dry for more than 45 consecutive days in the summer (June to August), and is moist throughout from mid November to February. Base saturation is greater than 75 percent throughout.
The A horizons has dry color of 10YR 6/2, 6/3, 6/4, 7/1, or 7/2, and moist colors of 10YR 3/2, 4/2, 4/3, 5,2 or 5/3. Some pedons do not have an Ap horizon. The Bt horizon has dry color of 10YR 6/3, 7/1, 7/2, 7/6, or 2.5Y 5/6 and moist color of 10YR 4/2, 4/3, 5/2, 5/6; 2.5Y 4/2, 5/4, or 5Y 5/4.
Textures are clay loam, sandy clay loam, gravelly clay loam, or silty clay loam. Gravel content ranges from 0 to 25 percent in the lower part.
COMPETING SERIES: These are the Arbuckle, Blasingame, Borden, Bressa, Creviscreek, Esparto, Fallbrook, Montpellier, Pomo, Ramona, Sesame, Snelling, Tivy, Wasioja, and Wyman series. Arbuckle, Borden, Creviscreek, Esparto, Montpellier, Ramona, Snelling, Wasioja and Wyman series are greater than 60 inches deep and are formed in alluvium. Blasingame, Bressa, Sesame, and Tivy series have a paralithic contact at 20 to 40 inches. Creviscreek soils are moderately well drained and have a soil reaction ranging from medium acid to neutral. Fallbrook soils have 15 to 28 percent coarse and very coarse sand. Pomo series has a lithic contact at 40 to 60 inches.
GEOGRAPHIC SETTING: Accelerator soils are on gently rolling to rolling hills and have slopes of 5 to 15 percent. The soils formed in material weathered from soft sandstone and siltstone. Elevation is 100 to 500 feet. The climate is subhumid mesothermal with hot dry summers and cool moist winter. Mean annual precipitation is 25 to 30 inches. Average January temperature is 48 degrees F; average July temperature is 65 degrees F; mean annual temperature is 56 to 58 degrees F. The frost-free season is 275 to 330 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Botella, Fagan, and Francisquito (T) series. Botella soils are greater than 60 inches deep, are formed in alluvium, and have a mollic epipedon. Fagan soils have a fine textural control section and have a mollic epipedon. Francisquito soils have a fine textural control section.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderately slow permeability.
USE AND VEGETATION: Used for rangeland, equestrian facilities, Christmas tree production, wildlife habitat, watershed and urban development. Vegetation is mainly annual grasses and forbs with scattered oaks.
DISTRIBUTION AND EXTENT: Coast ranges of central California. The soils are of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES PROPOSED: San Mateo County, California, 1985. Name from Stanford Linear Accelerator.
REMARKS:
Last revised by the state on 1/88.