LOCATION RINCON CA
Established Series
Rev. RE/LCL/RWK
08/2017
RINCON SERIES
The Rincon series consists of deep, well drained soils that formed in alluvium from sedimentary rocks. Rincon soils are on old alluvial fans and both stream and marine terraces, and have slopes of O to 30 percent. The mean annual precipitation is about 16 inches and the mean annual air temperature is about 60 degrees F.
TAXONOMIC CLASS: Fine, smectitic, thermic Mollic Haploxeralfs
TYPICAL PEDON: Rincon silty clay loam, dry farmed grain. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 4 inches; dark gray (10YR 4/1) silty clay loam, very dark gray (10YR 3/1) moist; medium size clods; hard, firm, sticky and plastic; many very fine and few medium roots; common very fine tubular pores; slightly acid (pH 6.5); clear wavy boundary. (4 to 10 inches thick)
A12--4 to 16 inches; dark gray (10YR 4/1) silty clay loam, very dark gray (10YR 3/1) moist; massive; very hard, firm, sticky and plastic; many very fine and few medium roots; common very fine, few fine and very few medium tubular pores; slightly acid (pH 6.5); gradual wavy boundary. (10 to 13 inches thick)
B21t--16 to 25 inches; dark grayish brown (10YR 4/2) sandy clay, very dark grayish brown (10YR 3/2) moist; weak coarse prismatic structure and strong moderate angular blocky; extremely hard, very firm, sticky and very plastic; common very fine roots; common very fine and few fine and medium tubular pores; many thin clay films on faces of peds and common moderately thick clay films lining pores; neutral (pH 7.0); gradual smooth boundary. (9 to 13 inches thick)
B22t--25 to 31 inches; dark grayish brown (10YR 4/2) sandy clay, very dark grayish brown (10YR 3/2) moist- coarse splotches of brown (10YR 5/3), brown (10YR 4/3) moist; moderate medium angular blocky structure; very hard, very firm, sticky and plastic; few very fine roots; common very fine and few fine and medium tubular pores; common thin clay films on faces of peds and lining pores; slightly effervescent, lime segregated in filaments; moderately alkaline (pH 7.9); gradual smooth boundary. (6 to 13 inches thick)
B3tca--31 to 40 inches; brown (10YR 5/3) sandy clay loam, brown (10YR 4/3) moist; weak medium angular blocky structure; very hard, firm, sticky and plastic; few very fine roots- very few fine and very fine tubular pores; few thin clay films on faces of peds and lining pores; strongly effervescent, lime segregated into soft masses and filaments; moderately alkaline (pH 8.0); gradual irregular boundary. (7 to 15 inches thick)
Cca--40 to 60 inches; yellowish brown (10YR 5/4) stratified sandy clay loam and sandy loam, dark yellowish brown (10YR 4/4) moist; massive; hard, firm, sticky and plastic; few very fine tubular pores; strongly effervescent, lime disseminated and segregated into filaments; moderately alkaline (pH 8.0).
TYPE LOCATION: Ventura County, California; 7,400 feet south and 4,200 feet east of the SW corner sec. 25, T.3N., R.21W., SBBM.
RANGE IN CHARACTERISTICS: The solum is 36 to 64 inches thick. Most pedons have essentially no gravel above the C horizon. The soils usually are moist in some or all parts between depths of 4 and 12 inches from November or early December until May. They usually are continuously dry the rest of the time. The mean annual soil temperature is between 59 degrees and 64 degrees F., and the soil temperature is continuously above 47 degrees F.
The A horizon is very dark gray, dark gray, gray, very dark grayish brown, dark grayish brown, or grayish brown; hue is mostly 10YR, in some pedons, it is 2.5Y. This horizon is loam, clay loam, or silty clay loam, and is usually clay loam. Usually the surface or all the Al horizon is hard and massive. If not massive, structure is destroyed after several years of cultivation. This horizon is hard or very hard. It contains about 2 percent organic matter. The A horizon is usually slightly acid to neutral. Some pedons may be medium acid or moderately alkaline in part because of cultural measures.
The B2t horizon is dark gray, dark grayish brown, grayish brown, light brownish gray, brown, yellowish brown, pale brown, light yellowish brown or light olive brown with the higher values and brighter chromas in the lower part in the interior of the peds. It is heavy clay loam, sandy clay or clay and has about 35 to 45 percent clay. The B2t horizon has about 6 to 10 percent more clay than the A horizon. It has weak prismatic to strong angular blocky structure. This horizon is neutral to moderately alkaline and alkalinity generally increases in the lower portion. Segregated lime is present in the lower part of the Bt horizon and upper C horizon. The boundary between the A horizon and B2t horizon is gradual or a transitional A3 or Bl horizon is present.
The C horizon is light gray, light brownish gray, pale brown, light yellowish brown or yellowish brown. It is usually clay loam, but stratification with other textures is present in some pedons. This horizon is mildly or moderately alkaline.
COMPETING SERIES: These are the
Azule series in this family and the
Contra Costa,
Danville,
Milpitas
Perkins,
Pleasanton,
Tierra,
Trabuco and
Zamora series in other families. Azule soils have clear A-B horizon boundaries with about 10 to 15 percent clay increase from A to B2 horizon. Contra Costa soils have a lithic contact at a depth of less than 40 inches. Danville soils have mollic epipedons. Milpitas and Tierra soils have abrupt A-B horizon boundaries with more than 15 percent clay increase. Perkins soils have reddish B2t horizons in hue of 7.5YR to 2.5YR. Pleasanton soils have less than 35 percent clay in the B2t horizon. Trabuco soils have hue of 2.5YR or 5YR in the B2t horizon. Zamora soils are silty and have less than 35 percent clay in the B2t horizon.
GEOGRAPHIC SETTING: Rincon soils are on older alluvial fans and both stream and marine terraces at elevations of 20 to 2,000 feet. Gradient is 0 to 30 percent. The soils formed in alluvium from sedimentary rocks. The climate is subhumid, mesothermal with warm, dry summers and cool, moist winters. The mean annual precipitation is about 12 to 20 inches. Average January temperature is about 45 degrees to 52 degrees F., average July temperature is about 68 degrees to 75 degrees F., mean annual temperature is about 59 degrees to 61 degrees F. The freeze-free season averages 200 to 300 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Altamont,
Antioch,
Azule,
Cropley,
Docas,
Lockwood, and
Sorrento soils. Altamont are hilly clay soils with slickensides. Antioch soils have natric horizons. Cropley soils are on fans and lack argillic horizons. Docas and Sorrento soils lack argillic horizons. Lockwood soils have mollic epipedons and have less than 35 percent clay in the argillic horizon.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; slow permeability.
USE AND VEGETATION: Used for irrigated citrus, deciduous fruits, row crops, and alfalfa. Some dry farming for grain and pasture. Natural vegetation is annual grasses and forbs.
DISTRIBUTION AND EXTENT: The soils are in the intermountain valleys of the Coast Range and along the west side of the lower Sacramento and Upper San Joaquin Valleys. The soils are extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Ventura Area California, 1917.
OSED scanned by SSQA. Last revised by state on 3/77.
Edited for errors 8/2017. -DEB
National Cooperative Soil Survey
U.S.A.