LOCATION LOPEZ CAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, thermic Lithic Ultic Haploxerolls
TYPICAL PEDON: Lopez shaly clay loam - annual grass and forbs. (Colors are for dry soil unless otherwise stated.)
A11--0 to 8 inches; dark gray (10YR 4/1) very shaly clay loam, very dark gray (10YR 3/1) moist; strong fine and medium granular structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine, fine, medium and coarse roots; many very fine and fine interstitial pores; about 15 percent by volume angular shale fragments larger than 3/4 inch, plus 30 percent about 2 mm; neutral (pH 6.8); gradual irregular boundary. (4 to 12 inches thick)
A12--8 to 14 inches; gray (10YR 5/1) very shaly clay loam, dark grayish brown (10YR 4/2) moist; strong fine and medium granular structure; slightly hard, very friable, sticky and slightly plastic; common very fine, fine, medium and coarse roots; many very fine and fine interstitial pores; about 40 percent shale fragments larger than 3/4 inch plus about 30 percent larger than 2 mm; neutral (pH 6.6); abrupt irregular boundary. (2 to 8 inches thick)
R--14 to 20 inches; hard fractured diatomaceous (Monterey) shale. Strata tilted at about 45 degree angle with few hard outcrops exposed. Rock joints are coated with thin dark brown clay films.
TYPE LOCATION: Santa Barbara County, California; 2 miles south from summit of Tepusquet and Bucklorn divide on Tepusquet Road, about 30 feet west from edge of road on hillside.
RANGE IN CHARACTERISTICS: Depth to a lithic contact of shale is 6 to 20 inches, usually about 14 inches. The mean annual temperature of the soil is about 59 degrees to 65 degrees F. and usually the soil temperature is not below 47 degrees F. at any time. The soil below a depth of about 5 inches usually is dry all of the time from late April or May until November or early December and usually is moist all the rest of the year. Fragments of shale occupy 35 to 50 percent of the volume of the soil profile.
The A horizon is a gray, dark gray, very dark gray, grayish brown, dark grayish brown or brown in 10YR or 2.5Y hue. Chroma is less than 3. This horizon is loam, silt loam, or clay loam. Laboratory determinations indicate more clay and greater cation exchange capacity than suggested by field texture. Soil properties are influenced to some extent by ash in the parent material and some amorphous material in the soil. Organic matter is 2 to 10 percent. The A horizon is neutral to moderately acid, usually about pH 6.0. Base saturation is 50 to 75 percent in some or all parts and is not less than 50 percent in any part. This horizon has moderate or strong granular or subangular blocky structure. Usually the A horizon rests directly upon rock but some pedons have a C horizon a few inches thick and paler than the A horizon.
COMPETING SERIES: These are the Crow Hill, Daulton, Friant, Gazos, Hambright, Lodo, Maymen, Montara, Santa Lucia, and Tollhouse series in other families. Crow Hill, Gazos, and Santa Lucia soils have a lithic or paralithic contact at depths of 24 to 40 inches. Daulton soils have a dark, hard and massive A horizon. Friant, Lodo, and Montara soils have less than 35 percent rock fragments. Hambright soils have a chroma of 2 or 3. Maymen soils have an ochric epipedon and an annual soil temperature less than 59 degrees F. Tollhouse soils have a paralithic contact at depths of less than 20 inches and have an annual soil temperature less than 59 degrees F.
GEOGRAPHIC SETTING: Lopez soils are on narrow divides and occur at elevations of 200 to 3,300 feet. Slopes range from 9 to 100 percent. The climate is dry subhumid mesothermal with cool to warm rainless but foggy summers near the coast and cool, moist winters. The mean annual precipitation is 12 to 30 inches. The average January temperature is 47 degrees to 51 degrees F., the average July temperature is 63 to 68 degrees F., and the mean annual temperature is about 58 to 62 degrees F. The annual freeze-free season is 200 to over 300 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Crow Hill, Gazos, Maymen, and Santa Lucia soils and the Chamise, Linne, and Los Osos soils. Chamise and Los Osos soils have an argillic horizon. Linne soils are strongly calcareous and have a paralithic contact at depths of 24 to 40 inches.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained; rapid to very rapid runoff; moderate permeability.
USE AND VEGETATION: Used for range and watershed. Vegetation is mostly coastal type sagebrush with scattered live oak and sparse annual grass and forbs. Some areas have a chaparral cover.
DISTRIBUTION AND EXTENT: Lopez soils occur in the central and south-central part of the Coast Range in California. The soils are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Monterey County, California, 1972.
REMARKS: The Lopez series was established to include soils that were formerly classified shallow phases of Santa Lucia and Crow Hill series.
The activity class was added to the classification in February of 2003. Competing series were not checked at that time. - ET