LOCATION ZAMORA CAEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, thermic Mollic Haploxeralfs
TYPICAL PEDON: Zamora silt loam - cultivated (Colors are for dry soil unless otherwise noted.)
Ap--0 to 10 inches; Grayish brown (2.5Y 5/2) silt loam, very dark grayish brown (10YR 3/2) moist; massive; hard, friable, slightly sticky, slightly plastic; many fine roots; common very fine pores; slightly acid (pH 6.3); clear wavy boundary. (8 to 14 inches thick)
B21t--10 to 24 inches; Brown (10YR 5/3) silty clay loam, dark brown (10YR 3/3) moist; weak coarse angular blocky structure; hard, friable, sticky, plastic; many fine roots; common very fine pores; few thin clay films on faces of peds and lining pores; neutral (pH 7.0); gradual wavy boundary. (12 to 15 inches thick)
B22t--24 to 40 inches; Brown (10YR 5/3) silty clay loam, dark brown (10YR 4/3) moist; weak coarse angular blocky structure; hard, friable, sticky, plastic; common fine roots; common very fine pores; continuous moderately thick clay films on faces of peds and lining pores; neutral (pH 7.0); gradual wavy boundary. (15 to 17 inches thick)
C1--40 to 51 inches; Yellowish brown (10YR 5/4) silt loam, dark yellowish brown (10YR 4/4) moist; massive; slightly hard, friable, slightly sticky, slightly plastic; common fine roots; common very fine pores; few thin clay films line pores; neutral (pH 7.0); clear wavy boundary. (10 to 15 inches thick)
C2--51 to 60 inches; Yellowish brown (10YR 5/4) gravelly loam, dark yellowish brown (10YR 4/4) moist; massive; slightly hard, friable, slightly sticky, slightly plastic; few fine roots; common very fine pores; slightly effervescent; lime segregated in concretions; slightly alkaline (pH 7.5).
TYPE LOCATION: Yolo County, California; about 3 miles north of Capay; 0.35 mile north of Road 16-A on Road 85, 45 feet east of Road 85, SW;/4NW1/4NW1/4 sec. 1, T.10N., R.2W.
RANGE IN CHARACTERISTICS: The solum ranges in thickness from 35 to 46 inches. The mean annual soil temperature ranges from about 59 degrees to 64 degrees F. These soils are continually moist between 4 and 12 inches from some time in November until April or May and dry the remainder of the year.
The A horizon is dark grayish brown, grayish brown, dark brown or brown; hue is 10YR or 2.5Y. It is fine sandy loam, loam, silt loam or light silty clay loam. The surface layer is both hard or very hard and massive when dry. The A horizon is about 2 to 4 percent organic matter. Reaction ranges from slightly acid to neutral.
The B2t horizon is dark grayish brown or brown, hue is 10YR or 7.5YR, and chroma is 2 or 3. It is clay loam or silty clay loam that contains less than 15 percent coarser than very fine sand. The upper boundary is diffuse, gradual or clear and some pedons have a transitional A3 horizon or B1 horizon. It has about 6 to 10 percent more clay absolute than the A horizon, but averages slightly less than 35 percent total clay. It is either massive or has blocky structure and ranges from neutral to slightly alkaline.
The C horizon is brown, grayish brown, yellowish brown, pale brown, light yellowish brown or light olive brown. Hue is 10YR or 2.5Y, value of 5 or 6, and chroma of 2, 3 or 4. Texture is clay loam, silt loam, loam, sandy loam or gravelly loam. In some pedons the lower part of the C horizon is stratified. The C horizon ranges from neutral to moderately alkaline and some pedons contain segregated lime and others lack it.
COMPETING SERIES: These are the Azule, Burchell, Los Robles, Modesto, Perkins, Pleasanton, Rincon, and Tehama series Azule and Rincon soils have 35 to 50 percent clay in the argillic horizon. Burchell, Modesto, Perkins, and Pleasanton soils are members of a fine-loamy family. In addition, Burchell soils are moderately to strongly alkaline in the argillic horizon. Modesto soils have an abrupt or clear boundary with 10 to 15 percent more clay in the arzillic horizon than in the epipedon. Perkins soils have 5YR or 2.5YR hue in the argillic horizon. Pleasanton soils have less than 18 to 25 percent clay in the argillic horizon. Los Robles soils have a cambic horizon and lack a 20 percent increase in clay from A horizon to B2 horizon. Tehama soils have moist values of 4 or more in the A horizon.
GEOGRAPHIC SETTING: Zamora soils are on nearly level to strongly sloping fans and terraces usually 0 to 9 percent slopes at elevations of 30 to 1,300 feet. The soils formed in alluvium from material weathered from mixed sedimentary rocks. They have a dry subhumid mesothermal climate with hot dry summers and cool moist winters. Mean annual precipitation ranges from 14 to 30 inches. Average January temperature is 45 degrees F., average July temperature is 75 degrees F., and mean annual temperature is 58 degrees to 63 degrees F. Average freeze-free season is about 250 to 330 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Los Robles and Rincon soils and the Brentwood, Salinas, Sorrento, and Yolo soils. Brentwood soils lack argillic horizons and have 35 to 40 percent clay in the textural control section. Salinas and Sorrento soils have a mollic epipedon. Yolo soils lack an argillic horizon, but are otherwise very similar.
DRAINAGE AND PERMEABILITY: Well-drained; glow to medium runoff; moderately slow permeability.
USE AND VEGETATION: The soils are used for growing orchards, row, field, and truck crops. Native vegetation is annual grasses and forbs and widely spaced oaks.
DISTRIBUTION AND EXTENT: Along the west side of the Sacramento Valley in central California and other parts of California. The soil is of moderate extent.
MLRA OFFICE RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Solano County (Suisun Area), California, 1936.
REMARKS: Zamora soils were formerly classified as Noncalcic Brown soils.
The activity class was added to the classification in January of 2003. Competing series were not checked at that time. - ET
OSED scanned by SSQA. Last revised by state on 1/73.