LOCATION VIZCAINO CAEstablished Series
TAXONOMIC CLASS: Loamy, mixed, superactive, isomesic, shallow Udic Argiustolls
TYPICAL PEDON: Vizcaino loam on southwest facing convex slope of 52 percent under annual and perennial grasses and forbs at 320 feet elevation. (Colors are for dry soil unless otherwise stated. When described on November 20, 1981 the soil was moist throughout).
A--0 to 2 inches; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; weak, very fine subangular blocky structure parting to weak very fine and fine granular; slightly hard, friable, slightly sticky and slightly plastic; common very fine roots; many very fine interstitial and common very fine tubular pores; 2 percent soft through hard angular and subangular pebbles (2-20mm); medium acid (pH 6.0); abrupt smooth boundary. (1 to 5 inches thick)
Bt1--2 to 13 inches; dark grayish brown (10YR 4/2) sandy clay loam, very dark brown (10YR 2/2) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and few fine roots; few very fine interstitial and common very fine and fine tubular pores; 2 percent soft through hard angular and subangular pebbles (2-40mm); few thin clay films on peds and in pores; medium acid (pH 5.8); clear wavy boundary. (6 to 15 inches thick)
Bt2--13 to 17 inches; dark grayish brown (10YR 4/2) gravelly clay loam, very dark grayish brown (10YR 3/2) moist; moderate very fine and fine subangular blocky structure; slightly hard, firm, slightly sticky and slightly plastic; common very fine roots; common very fine interstitial and tubular pores and few fine tubular pores; very few thin clay films on peds and in pores; 30 percent soft through hard angular and subangular pebbles (2-40mm); medium acid (pH 5.8); abrupt irregular boundary, (2 to 8 inches thick)
Crt--17 to 40 inches; folded and fractured soft through moderately hard, sandstone; few fine roots follow primary fractures; thin and moderately thick clay films coat primary fracture faces that are 5 to 30mm apart and less than 1mm wide.
TYPE LOCATION: Mendocino County, California; 200 yards north of the 73.11 milepost marker on Highway 1 north of Ft. Bragg to house on east side of highway; from the back of the house proceed up ranch access road. The site is located on the roadcut up from the first switchback about 400 feet up from the drainageway; 800 feet south and 1700 feet west of the northeast corner of sec. 20, T.20N., R.17W., MDBM, Inglenook quadrangle.
RANGE IN CHARACTERISTICS: Thickness of the solum, the mollic epipedon and depth to a paralithic contact ranges from 12 to 20 inches. The mollic epipedon has 0.6 to 4 percent organic carbon content. Mean annual soil temperature ranges from 56 to 59 degrees F. The difference between mean summer and mean winter soil temperature ranges from 5 to 9 degrees F. The soil between a depth of 5 and 17 inches or between a depth of 5 inches and bedrock, if depth to bedrock is less than 17 inches, is moist in all parts from November 1 to June 1 and is dry in all parts from July 15 to October 1 in most years. Base saturation (sum) ranges from 50 to 75 percent throughout. Reaction is medium or slightly acid.
The A horizon is 10YR 4/1, 4/2, 5/1, 5/2 or 5/3. Moist color is 2/1, 2/2, 3/2, or 3/3. Clay content ranges from 15 to 27 percent. Gravel content ranges from 2 to 15 percent.
The Bt horizon is 10YR 4/2, 5/2 or 5/3. Moist color is 10YR 2/2, 3/2 or 3/3. It is loam, clay loam or sandy clay loam and may be gravelly. Clay content ranges from 20 to 35 percent. Gravel content ranges from 0 to 35 percent. Gravel content increases with depth.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Vizcaino series occur on coastal mountains and hills that have rounded primary and secondary ridges and deep well defined dissections. Slopes are 9 to 75 percent. Elevations are 50 to 1300 feet. The soils formed in material weathered from sandstone. The climate is humid with cool foggy summers and cool moist winters. A strong marine influence limits the diurnal and annual range of temperature. Mean annual precipitation ranges from 40 to 55 inches. Mean January temperature is 48 degrees F., mean July temperature is 57 degrees F., mean annual temperature is 53 degrees F. The frost-free season is 250 to 330 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Abalobadiah Bruhel, Dehaven, Hotel, Irmulco, and Tramway soils. These soils occur on mountains to the east of the Vizcaino soils, are out of the influence of salt laden wind, have conifer vegetation and lack mollic epipedons. All are more than 20 inches deep. Abalobadiah soils are moderately deep and Bruhel soils are deep or very deep to a paralithic contact.
DRAINAGE AND PERMEABILITY: Well drained, surface runoff under bare soil conditions is medium through very rapid; moderate permeability.
USE AND VEGETATION: This soil is used for grazing, wildlife, and watershed. The vegetation is annual and perennial grasses and forbs where grazed. Where undisturbed, it is dense brush.
DISTRIBUTION AND EXTENT: Northern coastal California. The series is not extensive. MLRA 4.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Mendocino County, California, Western part, 1993.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon -- 0 to 17 inches (A, Bt1, Bt2).
Argillic horizon -- 7 to 17 inches (Bt1, Bt2)
Paralithic contact - the boundary at 17 inches (Crt horizon)