LOCATION MIRAMAR CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, isomesic Pachic Argiustolls
TYPICAL PEDON: Miramar loam; on an east-facing slope of 37 percent and at 275 feet in elevation under monkey flower, sage, poison oak. (Colors are for dry soil unless otherwise noted. When described July 17, 1984, the soil was slightly moist throughout.)
A1--0 to 7 inches; dark grayish brown (10YR 4/2) loam, very dark gray (10YR 3/1) moist; strong fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine, and few medium roots; many very fine and fine tubular and interstitial pores; 5 percent 2 to 5 mm pebbles; neutral (pH 7.0); clear wavy boundary. (5 to 10 inches thick)
A2--7 to 15 inches; dark grayish brown (10YR 4/2) loam, very dark gray (10YR 3/1) moist; moderate coarse subangular blocky structure parting to moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, fine, and medium roots; common very fine tubular and interstitial pores; 5 percent 2 to 5 mm pebbles; slightly acid (pH 6.5); clear wavy boundary. (5 to 10 inches thick)
Bt--15 to 24 inches; brown (10YR 5/3) clay loam, dark brown (10YR 3/3) moist; weak coarse subangular blocky structure; slightly hard, friable, sticky and plastic; few very fine and fine roots; common very fine tubular and interstitial pores; few thin clay films; 2 percent 2 to 5 mm pebbles; slightly acid (pH 6.5); clear wavy boundary. (6 to 12 inches thick)
BC--24 to 29 inches; yellowish brown (10YR 5/4) loam, dark brown (10YR 4/3) moist; weak coarse subangular blocky structure; slightly hard, friable, slightly sticky and plastic; few very fine and fine roots; common very fine tubular pores; 5 percent 2 to 5 mm pebbles; slightly acid (pH 6.5); clear wavy boundary. (4 to 8 inches thick)
Cr--29 inches; weathered quartz diorite that can be broken easily with tile spade.
TYPE LOCATION: San Mateo County, California; 1/2 mile north of Montara; 1,400 feet north and 750 feet east of intersection of Martini Creek and State Highway 1. The area is unsectionized.
RANGE IN CHARACTERISTICS: Depth to a paralithic contact is 20 to 40 inches. The mean annual soil temperature is 56 to 58 degrees F and is usually not below 47 degrees F at any time. The difference between mean winter and mean summer soil temperature is less than 9 degrees F. The soil moisture control section is moist throughout the solum from mid-November through 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. Organic matter content is 1 percent or more to a depth of 20 inches or more. It is slightly acid or neutral throughout the solum. Gravel content is between 2 to 10 percent throughout the profile.
The A horizons are 10YR 3/2, 4/2, or 5/2 dry and 10YR 2/1, 2/2, 3/1, or 3/2 moist. Texture is loam or coarse sandy loam.
The Bt horizons are 10YR 3/4, 5/3, 5/4, or 5/6 dry and 10YR 2/3 or 3/3 moist. Textures are sandy clay loam or clay loam.
The BC horizon is 10YR 5/4, 5/6 or 7.5Y 6/5 dry and 10YR 4/3, 5/6 or 7.5YR 5/6 moist. Texture is loam.
COMPETING SERIES: These are the Abalobadiah (T), Bruhel (T), and Candlestick (T) soils in the same family. Abalobadiah (T) soils are formed in material weathered from sandstone and the gravel content is greater than 10 percent. Candlestick (T) soils are 20 to 40 inches to a lithic contact. Bruhel soils are more than 40 inches deep.
GEOGRAPHIC SETTING: The Miramar soils are on coastal hills and mountains and have slopes of 9 to 75 percent. They are at elevations of 200 to 2,000 feet. The climate is moist subhumid with cool moist summers and cool moist winters. Mean annual precipitation is 20 to 45 inches. Average January temperature is 48 degrees F, average July temperature is 60 degrees F, and mean annual temperature is about 54 to 56 degrees F. Frost-free season is 275 to 350 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Barnabe, Bret (T), Buriburi (T), Candlestick (T), and Scarper (T) soils. The Barnabe and Bret soils are less than 20 inches to sandstone. Buriburi and Scarper soils lack an argillic horizon. Candlestick soils are underlain by hard sandstone.
DRAINAGE AND PERMEABILITY: Well drained; medium to very rapid runoff; moderately slow permeability.
USE AND VEGETATION: Used mainly for watershed, wildlife, and some recreation development. Vegetation is mainly coastal shrubs.
DISTRIBUTION AND EXTENT: Northern Santa Cruz Ranges in San Mateo County. The soils are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: San Mateo County, California 1960.
REMARKS: This is a classification change from fine-loamy, mixed, mesic Pachic Argixerolls to fine-loamy, mixed, isomesic Pachic Argiustolls.
The activity class was added to the classification in February of 2003. Competing series were not checked at that time. - ET
Other characteristics:
3.1 Mean annual soil temperature at a depth of 18 inches if less than 59 degrees F, but never below 47 degrees. Less than 9 degrees F difference between mean summer and mean winter soil temperature.
3.2 Soil is dry in all or some parts for 3 months or more cummulative.
3.3 Temperature and moisture data are from transect in San Mateo County.