LOCATION SUMIWAWA CAEstablished Series
TAXONOMIC CLASS: Mixed, thermic, shallow Typic Xeropsamments
TYPICAL PEDON: Sumiwawa gravelly loamy sand, in an area of Rock Outcrop-Sumiwawa-Hipuk Complex, 30 to 75 percent slopes; on the side of a mountain at an elevation of 1,460 feet. (Colors are for dry soil unless otherwise noted) 1 percent stones, 4 percent cobbles, 25 percent gravel on soil surface.
A1--0 to 0.5 inches (0 to 1.25 centimeters); pale brown (10YR 6/3) gravelly loamy sand, brown (10YR 5/3) moist; weak thin platy structure; soft, very friable, nonsticky and nonplastic; common very fine roots, many very fine interstitial pores; 25 percent gravel; slightly acid (pH 6.5); abrupt wavy boundary. (0 to 2 inches thick)
A2--0.5 to 9.5 inches (1.25 to 24 centimeters); pale brown (10YR 6/3) gravelly loamy sand, brown (10YR 4/3) moist; weak medium and coarse subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine roots; many very fine interstitial pores; 30 percent gravel; slightly acid (pH 6.3); abrupt wavy boundary. (4 to 12 inches thick)
C--9.5 to 13 inches (24 to 32.5 centimeters); pale brown (10YR 6/3) loamy sand, brown (10YR 4/3) moist; massive; soft, very friable, nonsticky and nonplastic; common very fine and fine roots; common very fine interstitial pores; 12 percent gravel; slightly acid (pH 6.3); clear wavy boundary. (2 to 10 inches thick)
Cr--13 to 22 inches (32.5 to 55 centimeters); soft, easily diggable, sandstone; few fine roots; abrupt smooth boundary.
R--22 to 24 inches (55 to 60 centimeters); hard, without apparent fractures, sandstone.
TYPE LOCATION: Los Angeles County, California; about 1/2 mile south of Calabasas Peak; 2850 feet west 800 feet north of the southeast corner of section 3, T. 1 S., R. 17 W.; Latitude 34 degrees, 6 minutes, 24 seconds north and Longitude 118 degrees, 39 minutes, 0 seconds west; Malibu Beach Quadrangle.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature: 62 to 66 degrees F.
Soil moisture: Soil is moist in middle to late November to late May.
Depth to paralithic contact: 10 to 20 inches.
Depth to lithic contact: 20 to 40 inches.
A horizon--10YR 6/3, 5/3; 10YR 5/3, 4/3 moist.
Clay percentage--2 to 8 percent.
Coarse fragments--15 to 30 percent.
C horizon--10YR 6/3, 5/3; 10YR 5/3, 4/3 moist.
Clay percentage--2 to 8 percent.
Coarse fragments--5 to 30 percent.
COMPETING SERIES: This is the Pismo series. Pismo soils lack an R horizon directly under the Cr horizon, and can have chroma of 1. Pismo soils also do not have coarse fragments in the profile.
GEOGRAPHIC SETTING: Sumiwawa soils on are side slopes of hills and mountains and have slopes of 30 to 75 percent. They formed in residuum and colluvium derived from sandstone at elevations of 1,400 to 2,500 feet. The mean annual precipitation is 18 to 24 inches. Mean annual temperature is 60 to 64 degrees F. The frost-free season is 290 to 350 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Hipuk (T), Kawenga (T) and Zumaridge (T) soils. All these soils occur on the side slopes of hills and mountains. Hipuk and Kawenga soils have argillic horizons and have fine-loamy particle size families. Zumaridge soils have mollic epipedons and lithic contacts above 20 inches.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained; high runoff; rapid permeability.
USE AND VEGETATION: Used for recreation, building site development and wildlife habitat. Vegetation is chamise ceonothus, Laurel sumac, and miscellaneous forbs and grasses.
DISTRIBUTION AND EXTENT: Los Angeles County, California. The soil is of limited extent. MLRA 20.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.
SERIES PROPOSED: Los Angeles County, California, 2000.
Remarks: The series name is from a local American Indian name. Diagnostic horizons and features recognized in this pedon:
Ochric epipedon--The zone from the soil surface to a depth of about 9.5 inches (A1 and A2 horizons).
Paralithic material--The zone from a depth of 13 inches to about 22 inches (Cr horizon).
Lithic contact--The zone at about 22 inches (R horizon).