LOCATION BURIBURI CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, isomesic Pachic Haplustolls
TYPICAL PEDON: Buriburi gravelly loam; on a west facing slope of 30 percent in a eucalyptus grove on San Bruno Mountain at 800 feet in elevation. (Colors are for very soil unless otherwise noted. When described June 11, 1983, the soil was moist throughout.)
O--2 inches to 0; decomposed and undecomposed eucalyptus leaves, twigs, and berry vines. (0 to 3 inches thick)
A1--0 to 3 inches; dark grayish brown (10YR 4/2) gravelly loam, dark brown (10YR 3/3) moist; moderate medium and coarse subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine to medium roots; many very fine tubular and interstitial pores; 20 percent 2 to 40 mm pebbles; moderately acid (pH 5.6); clear, smooth boundary. (3 to 5 inches thick)
A2--3 to 10 inches; grayish brown (10YR 5/2) gravelly loam; very dark grayish brown (10YR 3/2) moist; moderate medium and coarse subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine to medium roots; many very fine tubular and interstitial, and few coarse tubular pores; 18 percent 2 to 40 mm pebbles; moderately acid (pH 5.6); diffuse, smooth boundary. (4 to 10 inches thick)
A3--10 to 16 inches; grayish brown (10YR 5/2) gravelly loam, very dark grayish brown (10YR 3/2) moist; moderate fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine, fine, and few medium roots; many very fine tubular and interstitial, and few coarse tubular pores; 20 percent 2 to 40 mm pebbles; moderately acid (pH 6.0); diffuse, smooth boundary. (3 to 8 inches thick)
A4--16 to 30 inches; grayish brown (10YR 5/2) gravelly loam, very dark grayish brown (10YR 3/2) moist; weak fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine, fine, and few medium roots; many very fine and fine tubular and interstitial pores; 24 percent 2 to 40 mm pebbles; moderately acid (pH 6.0); clear, irregular boundary. (10 to 17 inches thick)
R--30 to 35 inches; hard, fractured sandstone.
TYPE LOCATION: San Mateo County, California; on San Bruno Mountain; 1,000 feet south on Radio Road from intersection of Guadalupe Canyon Parkway and 150 feet east of Radio Road. This area is not sectionized.
RANGE IN CHARACTERISTICS: Depth to a lithic contact of sandstone is 20 to 40 inches. The mean annual soil temperature is 56 to 58 degrees F. The difference between mean winter and mean summer soil temperature is less than 9 degrees F. Organic matter content is greater than 1 percent throughout the solum. The soil between the depth of 5 to 15 inches is moist throughout from mid-November to June. It is dry in some or all parts the rest of the time but is not dry in all parts for 45 consecutive days. Gravel content averages 5 to 35 percent throughout the profile.
The A horizon has dry color of 10YR 4/2, 4/3, 5/2, or 5/3, and moist color of 10YR 2/2, 3/1, 3/2, or 3/3. Textures are gravelly loam and loam and the estimated clay content ranges from 18 to 27 percent. Structure is weak to moderate medium to coarse subangular blocky or strong fine to medium granular.
COMPETING SERIES: This is the Kehoe series. The Kehoe series has a paralithic contact.
GEOGRAPHIC SETTING: Buriburi soils are steep to very steep and have slopes of 30 to 75 percent. They formed in material weathered from hard fractured sandstone. Elevations are 200 to 1,350 feet. The climate is subhumid with cool, foggy summers and cool, moist winters. Mean annual precipitation is 20 to 30 inches. Mean January temperature is about 48 degrees F; mean July temperature is 60 degrees F.; and mean annual temperature is 54 to 56 degrees F. The frost free season is about 300 to 350 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Barnabe, Candlestick, and Kron soils. Barnabe and Kron soils are 10 to 20 inches to a lithic contact. Candlestick soils have an argillic horizon.
DRAINAGE AND PERMEABILITY: Well drained; rapid to very rapid runoff; moderate permeability.
USE AND VEGETATION: Used for watershed, wildlife, recreation and urban development. Vegetation consists of shrub, annual grasses, and scattered eucalyptus with understories of ferns, berries, and poison oak.
DISTRIBUTION AND EXTENT: Upland areas of central coastal California that receive summer fog The soils are of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: San Mateo County, 1984. Name coined from Buri Buri Ridge in San Mateo County.
REMARKS: The activity class was added to the classification in January of 2003. Competing series were not checked at that time. - ET