LOCATION CAPISTRANO CAEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, thermic Entic Haploxerolls
TYPICAL PEDON: Capistrano sandy loam, rangeland. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 5 inches; dark grayish brown (10YR 4/2) sandy loam, very dark brown (10YR 2/2) moist; weak fine granular structure; slightly hard, very friable, nonsticky and nonplastic; common very fine roots; common very fine tubular and interstitial pores; moderately acid (pH 6.0); abrupt smooth boundary. (4 to 8 inches thick)
A1--5 to 16 inches; dark grayish brown (10YR 4/2) sandy loam, very dark brown (10YR 2/2) moist; massive; slightly hard, very friable, nonsticky and nonplastic; common very fine roots; few very fine tubular, common very fine interstitial pores; moderately acid (pH 6.0); gradual smooth boundary. (7 to 17 inches thick)
A2--16 to 27 inches; grayish brown (10YR 5/2) sandy loam, very dark grayish brown (10YR 3/2) moist; massive; slightly hard, very friable, nonsticky and nonplastic; common very fine roots; few very fine tubular, common very fine interstitial pores; moderately acid (pH 6.0); gradual smooth boundary. (7 to 16 inches thick)
C--27 to 65 inches; grayish brown (10YR 5/2) sandy loam, very dark grayish brown (10YR 3/2) moist; massive; slightly hard, very friable, nonsticky and nonplastic; few very fine roots; few very fine tubular and interstitial pores; moderately acid (pH 6.0).
TYPE LOCATION: Orange County, California; about 4,600 feet north-northeast of Trabuco Road and 200 feet northwest of Canada Road, Rancho Los Alisos; SW 1/4 SE 1/4 of section 11 (projected), T. 6 S., R. 8 W.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 60 degrees to 65 degrees F. at depth of 20 inches and the soil temperature is usually not below 47 degrees F. at any time. The soil between depths of 8 and 25 inches is continuously dry in all parts from late April or May until late October and is usually moist in some part all the rest of the year. The 10- to 40-inch control section and usually all parts of the profile are sandy loam, coarse sandy loam or fine sandy loam and have less than 18 percent clay. The average combined silt, very fine sand and clay is assumed to be less than 50 percent. No distinct stratification is present. Rock fragments in the control section range from 0 to 3 percent, by volume, and are usually less than 3 inches in diameter.
The A horizon is dark brown, brown, grayish brown, or dark grayish brown in 10YR hue. It is assumed to have 1.5 to 3 percent organic matter in the upper 10 inches and organic matter decreases gradually to less than 1 percent at a depth of 20 inches. This horizon has weak granular or weak subangular blocky structure or is massive. It is neutral to medium acid.
The C horizon is brown, light yellowish brown, brownish yellow, or grayish brown. It is moderately acid to slightly alkaline and is non-calcareous.
COMPETING SERIES: This is the Yettem series. Yettem soils have a mean annual soil temperature of 64 to 67 degrees F., and have greater than 20 degrees difference between winter and summer soil and air temperatures.
GEOGRAPHIC SETTING: Capistrano soils are on alluvial fans and flood plains in small valley areas at elevations of 25 to 2,500 feet. Slopes range from 0 to 15 percent. The soils formed in moderately coarse textured alluvium derived from sedimentary or granitic sources. The climate is dry subhumid, mesothermal with cool moist winters and somewhat dry foggy summers. The mean annual temperature is about 62 degrees F. The average frost-free season is 240 to 340 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These re the Alo, Bosanko, Cieneba, Corralitos, Fontana, Lockwood, and Solano soils and the competing San Andreas soils. Alo and Bosanko soils are fine textured, have deep cracks when dry, and a paralithic contact at depths of 20 to 40 inches. Cieneba soils have ochric epipedons and a paralithic contact at depths of less than 20 inches. Corralitos soils are sandy and have ochric epipedons. Fontana soils have fine-loamy particle size families and have a paralithic contact at depths of 20 to 40 inches. Lockwood soils have an argillic horizon.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderately rapid permeability.
USE AND VEGETATION: Used for citrus and dry land barley, pasture, and range. Uncultivated areas have annual grasses and forbs with scattered brush; some areas have a few oak trees.
DISTRIBUTION AND EXTENT: Coastal part of southern California. The soils are not extensive.
MLRA OFFICE RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Orange and Western Part of Riverside Counties, California, 1974.
REMARKS:
Horizonation updated June 2001. Color of A2 horizon was changed to 10YR 5/2 (3/2 moist) from a letter dated April 1974 from Grant Kennedy to distinguish the A1 and A2 horizons.