LOCATION SEABACK CAEstablished Series
TAXONOMIC CLASS: Loamy, mixed, superactive, thermic, shallow Calcic Haploxerepts
TYPICAL PEDON: Seaback loam - on an east southeast-facing slope of 15 percent, under annual grass and native shrubs at 695 meters (2,080 feet) elevation. (Colors are for dry soil unless otherwise stated. When described on June 7, 1983 was slightly moist from 0 to 9 inches deep and moist below 9 inches deep.)
A--0 to 23 centimeters (0 to 9 inches); light brownish gray (10YR 6/2) loam, dark grayish brown (10YR 4/2) moist; surface is crusted; fine weak subangular blocky structure; slightly hard, friable, slightly sticky and plastic; few very fine roots; few very fine tubular and interstitial pores; violently effervescent with disseminated carbonates; moderately alkaline (pH 8.0); gradual smooth boundary. (8 to 25 centimeters (3 to 10 inches) thick)
Bk--23 to 48 centimeters (9 to 19 inches); pale brown (10YR 6/3) loam, brown (10YR 4/3) moist; massive; slightly hard, friable, slightly sticky and plastic; few very fine roots; few very fine and fine tubular pores; violently effervescent with carbonates disseminated and segregated as few fine soft filaments; moderately alkaline (pH 8.0); clear wavy boundary. (10 to 25 centimeters (4 to 10 inches) thick)
Cr--48 to 58 centimeters (19 to 23 inches); soft calcareous sandstone fractured into fragments 1 to 8 centimeters (1/2 to 3 inches) across.
TYPE LOCATION: San Luis Obispo County, California; approximately 6.3 miles north of the junction of Highway 58 on the Simmler-Bitterwater Road, then 3,500 feet east; 2,100 feet south and 2,100 feet west of the northeast corner of sec. 30, T. 28 S., R. 18 E., Mount Diablo Base and Meridian. USGS La Panza NE, California Quadrangle; latitude 35 degrees, 27 minutes, 48 seconds N and long. 120 degrees, 4 minutes, 28 seconds W.
RANGE IN CHARACTERISTICS: Depth to soft calcareous sandstone or conglomerate is 25 to 50 centimeters (10 to 20 inches). Mean annual soil temperature ranges from 16 to 20 degrees C (60 to 68 degrees F). The moisture control section becomes moist in some or all parts between November 15 and January 15, and remains moist until April 15 to May 15. Soil temperature is always above 8 degrees C (47 degrees F). Clay content ranges from 12 to 30 percent. Gravel content is 0 to 5 percent by volume.
The A horizon has dry color of 10YR 6/3, 6/2, 5/2; 2.5Y 6/3, 6/2 and moist color of 10YR 4/3, 4/2, 3/3; 2.5Y 4/3 or 4/2. Textures are sandy loam, loam or light clay loam. It is strongly to violently effervescent.
The C horizon has dry color of 10YR 6/3, 5/4, 5/2; 2.5Y 6/3, 5/4 and moist color of 10YR 5/4, 5/3, 4/4, 4/3, 4/2; 2/5Y 4/4. Textures are sandy loam, loam or light clay loam.
COMPETING SERIES: There are no other series in this family. The Panoza soils are moderately deep to soft bedrock.
GEOGRAPHIC SETTING: Seaback soils are on hills and mountains and have slopes of 9 to 75 percent. The soil is formed in material weathered from soft calcareous sandstone, shale or conglomerate. Elevations are 549 to 1,259 meters (1,800 to 4,100 feet). The climate is semiarid with hot dry summers and cool moist winters. Mean annual precipitation is 203 to 305 millimeters (8 to 12 inches). Average January temperature is about 8 degrees C (46 degrees F), the average July temperature is about 25 degrees C (77 degrees F.), and the mean annual temperature is about 14 to 17 degrees C (58 to 62 degrees F). The average frost-free season is about 175 to 225 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Hillbrick, Jenks (T), Padres (T) and Panoza (T) soils. Hillbrick soils have a lithic contact. Jenks (T) and Panoza (T) soils are moderately deep. Padres soils are deep and are on alluvial plains.
DRAINAGE AND PERMEABILITY: Well drained, medium to high runoff; moderate permeability.
USE AND VEGETATION: This soil is used for livestock grazing and some dry-farmed small grain. Vegetation is mainly red brome, filaree and other annual grasses and forbs.
DISTRIBUTION AND EXTENT: Hills and mountains of the San Juan Hills and the La Panza and Temblor Ranges in California in MLRA 15. The soils are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES PROPOSED: San Luis Obispo County, California; Carrizo Plain Area, 2000. Soil name was derived from Seaback Ranch.
REMARKS: Ochric epipedon - 0 to 8 centimeters (0 to 3 inches)
Cambic horizon - 8 to 28 centimeters (3 to 11 inches); based on development of color and structure.
Calcareous class - pedon is violently effervescent throughout.
Seaback soils have a xeric bordering on aridic moisture regime.
ADDITIONAL DATA: