LOCATION GABINO CAEstablished Series
TAXONOMIC CLASS: Fine, smectitic, thermic Typic Argixerolls
TYPICAL PEDON: Gabino gravelly clay loam, rangeland. (Colors are for dry soil unless otherwise noted.)
A11--0 to 5 inches; brown (10YR 5/3) gravelly clay loam, dark brown (7.5YR 3/2) moist; weak coarse prismatic structure parting to weak medium subangular blocky; hard, friable, sticky and plastic; common very fine roots; common very fine tubular pores; 15 percent pebbles (by volume); medium acid (pH 6.0); clear smooth boundary. (3 to 6 inches thick)
A12--5 to 10 inches; brown (10YR 5/3) gravelly clay loam, dark brown (7.5YR 3/2) moist; weak fine and medium subangular blocky structure; hard, friable, sticky and plastic; common very fine roots; common very fine tubular pores; 15 percent pebbles (by volume); medium acid (pH 6.0); clear smooth boundary. (3 to 6 inches thick)
B21t--10 to 26 inches; reddish brown (5YR 4/3) gravelly clay, dark reddish brown (5YR 3/3) moist; strong coarse prismatic structure; extremely hard, very firm, very sticky and very plastic; few very fine roots; few very fine pores; many moderately thick clay films on faces of peds; 15 percent pebbles (by volume); slightly acid (pH 6.5); diffuse smooth boundary. (12 to 16 inches thick)
B22t--26 to 38 inches; reddish brown (5YR 4/3) gravelly clay, dark reddish brown (5YR 3/3) moist; strong coarse prismatic structure; extremely hard, very firm, very sticky and very plastic; few very fine roots; few very fine pores; many moderately thick clay films on faces of peds; 15 percent pebbles (by volume); mildly alkaline (pH 7.5); abrupt smooth boundary. (8 to 12 inches thick)
Cr--38 to 50 inches; weakly consolidated conglomerate; mixed rounded crystalline pebbles and cobbles; some strongly weathered.
TYPE LOCATION: Orange County, California; about 2,800 feet east of Gabino Canyon, Rancho Mission Viejo; NW1/4 NE1/4 sec. 33, T.7S., R.6W.
RANGE IN CHARACTERISTICS: Depth to a paralithic contact is 24 to 40 inches. The mean annual soil temperature is 60 to 65 degrees F. at depth of 20 inches and the soil temperature is usually not below 46 degrees F. at any time. The soil between depths of about 6 and 16 inches is continuously dry in all parts from late April or May until late October or November and is usually moist in some part or all the rest of the year. The soil usually contains pebbles or cobbles or both throughout and has from 10 to 30 percent (by volume) in both the A and B2t horizons. These soils have 1 to 4 percent organic matter to depth of 10 inches and the amount decreases regularly to less than 1 percent at depth of about 15 inches. Base saturation is between 80 and 100 percent throughout the profile.
The A horizon is brown or dark brown (10YR 3/3, 4/3, 5/3) gravelly or cobbly loam or clay loam. It has weak or moderate granular or subangular blocky or weak prismatic structure, parting to weak subangular blocky. This horizon is slightly hard or hard and is medium or slightly acid. Some pedons have horizons transitional to the B2t horizon and have either B1 or A3 horizons or both.
The B2t horizon is dark reddish gray or reddish brown (5YR 4/2, 4/3, 5/3) gravelly or cobbly clay or gravelly or cobbly sandy clay. It is slightly acid to mildly alkaline and generally increases in alkalinity as depth increases.
COMPETING SERIES: These are the Fagan, Los Osos, Sespe, Sween and Todos series. Fagan and Todos soils are 40 to 60 inches deep to weathered sandstone and shale. Los Osos and Sween soils have B horizon hue of 10YR or 2.5Y. Sespe soils have less than 10 percent rock fragments in the solum, and have 7.5YR or 5YR hue in the A horizon.
GEOGRAPHIC SETTING: Gabino soils are on stream terraces. Slopes are 15 to 50 percent. Elevations are 200 to 2,500 feet. The soils formed in softly consolidated gravelly and cobbly sandy deposits. The climate is dry subhumid, mesothermal with warm, somewhat foggy, dry summers and cool moist winters. Mean annual precipitation is 12 to 20 inches; mean annual temperature is 60 to 63 degrees F., average July temperature is about 69 to 74 degrees F. The frost-free season is about 290 to 350 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Alo, Fontana, Modjeska, Solano, Soboba and Yorba soils. Alo and Fontana soils lack a B2t horizon and have a Cca horizon. Modjeska and Soboba soils lack mollic epipedons and B2t horizons and both have 35 percent or more rock fragments. Solano soils have natric horizons with less than 35 percent clay and lack rock fragments. Yorba soils lack mollic epipedons and have B2t horizons with more than 35 percent rock fragments.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; slow permeability.
USE AND VEGETATION: Used for dryland pasture, rangeland, and watershed. Principal vegetation is annual grasses and forbs, stipa, and some native brush.
DISTRIBUTION AND EXTENT: Southern California. The soils are inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Orange and Western Part of Riverside Counties, California, 1974.
OSED scanned by SSQA. Last revised by state on 6/76.