LOCATION STILL CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, thermic Cumulic Haploxerolls
TYPICAL PEDON: Still clay loam, cultivated. (Colors are for dry soil unless otherwise noted.)
Ap--O to 8 inches; dark grayish brown (10YR 4/2) clay loam, very dark gray (10YR 3/1) moist; moderate medium granular structure; hard, friable, sticky and plastic; many very fine and fine roots; many very fine, common fine and medium tubular pores; slightly acid (pH 6.5); clear smooth boundary. (5 to 10 inches thick)
A12--8 to 25 inches; dark grayish brown (10YR 4/2) clay loam, very dark gray (10YR 3/1) moist; weak medium subangular blocky structure; hard, friable, sticky and plastic; many very fine and fine roots- many very fine, common fine and medium tubular pores; slightly acid (pH 6.5); gradual wavy boundary. (15 to 20 inches thick )
C1--25 to 34 inches; grayish brown (10YR 5/2) clay loam, very dark grayish brown (10YR 3/2) moist; weak medium subangular blocky structure; slightly hard, friable, sticky and plastic; common very fine roots; many very fine, common fine and few medium tubular pores; moderately alkaline (pH 8.0); clear smooth boundary. (7 to 15 inches thick)
IIAb--34 to 53 inches; dark grayish brown (10YR 4/2) clay loam; very dark gray (10YR 3/1) moist; moderate coarse subangular blocky structure; very hard, firm, sticky and plastic; few very fine roots; many very fine, common fine and few medium tubular pores; moderately alkaline (pH 8.0); gradual wavy boundary. (12 to 20 inches thick)
IIC2--53 to 60 inches; brown (10YR 5/3) clay loam, dark brown (10YR 3/3) moist; weak coarse subangular blocky structure; hard, friable, sticky and plastic; many very fine and common fine tubular pores; moderately alkaline (pH 8.0).
TYPE LOCATION: San Luis Obispo County, California- located about 1/4 mile east of El Camino Real on Quarry Road in the Santa Margarite Land Grant, T.29S., R.13E.
RANGE IN CHARACTERISTICS: Mean annual soil temperature ranges from 59 degrees to 62 degrees F. The moisture control section is moist in some part from December until May and is dry in all parts from July until October. The soils are either stratified or they have buried A horizons. They have 1 to 4 percent organic matter to a depth of 27 or more inches and the organic matter decreases irregularly with increasing deptb. Rock fragments, mostly gravel, make up O to 35 percent of the soil by volume.
The A horizon is grayish brown, dark grayish brown or dark gray (2.5Y 5/2, 4/2; lOYR 5/2, 5/1, 4/2, 4/1, 3/1) dry and very dark grayish brown or very dark gray (2.5Y 3/2; lOYR 3/1, 3/2) moist. It is clay loam, sandy clay loam, gravelly sandy clay loam or gravelly clay loam. This horizon is slightly acid or neutral.
The C horizon is brown or grayish brown (2.5Y 5/2; 10YR 6/2, 5/2, 5/3) dry and very dark grayish brown, very dark gray or dark brown (10YR 3/1, 3/2, 3/3; 2.5Y 3/2) moist. Some pedons have mottles below 30 inches that are brown, dark brown, or yellowish brown (10YR 5/3, 4/3) dry. The 10- to 40-inch control section is clay loam, loam, or gravelly loam or gravelly clay loam. This horizon is slightly acid to moderately alkaline.
The IIAb horizon is gray, dark gray, grayish brown or brown (10YR 5/1, 4/1, 5/2, 4/2, 5/3; 2.5Y 5/2). It is clay loam or loam. Some pedons have disseminated lime. In some pedons it is gravelly sandy loam below a depth of 40 inches.
COMPETING SERIES: These are the Elder, Linne, Marimel, Mocho, Salinas, San Benito, Sorrento and Vina series. Elder soils contain less than 18 percent clay. Linne and San Benito soils are less than 40 inches deep to a paralithic contact and have horizons with segregated lime. Marimel soils are somewhat poorly drained and have mottles in the lower part of the profile. Mocho soils have mollic epipedons less than 20 inches thick and are calcareous throughout. Salinas soils have horizons with segregated lime and the Organic matter decreases regularly with incresing deptb. Sorrento soils have mollic epipedons less than 20 inches thick and the organic matter decreases regularly with increasing depth. Vina soils are both hard and massive below depths of 10 to 18 inches.
GEOGRAPHIC SETTING: Still soils are on flood plains and alluvial fans and have gradients of O to 30 percent. They forned in alluvial material from sedimentary rocks. Elevations are 600 to 2,000 feet. The climate is subhumid mesothermal with warm dry summers and cool moist winters. Mean annual precipitation is 12 to 25 inches. Average January temperature is about 46 degrees F., the average July temperature is about 71 degrees F., and the mean annual temperature is about 57 degrees to 61 degrees F. The average frost-free season is about 175 to 240 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Arbuckle, Clear Lake, Elder, Linne, Lockwood and Gazos soils. Arbuckle soils have an ochric epipedon and have argillic horizons. Clear Lake soils average more than 40 percent clay throughout. Lockwood soils have an argillic horizon and the organic matter decreases regularly with increasing depth. Gazos soils have a lithic contact at depths of 20 to 40 inches.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderately slow permeability.
USE AND VEGETATION: The soil is used for cultivated alfalfa, sugar beets and dryfarmed grain. Natural vegetatlon is mainly annual grasses with scattered oaks.
DISTRIBUTION AND EXTENT: Valleys of the south half of the Coast Range in California. The soils are inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: San Luis Obispo County, California, Paso Robles Area, 1977.
REMARKS: The activity class was added to the classification in February of 2003. Competing series were not checked at that time. - ET
A Still taxadjunct pedon was sampled in Pinnacles National Monument in 2006 - Pedon No 06N0207. The pedon was a taxadjunct due to silty clay loam textures below 40 inches that was strongly to violently effervescent - SBS
OSED scanned by SSQA. Last revised by state on 10/77.