Established Series


The Anderson series have brown, medium acid, gravelly loam A horizons and reddish brown, slightly acid, very gravelly sandy loam C horizons.

TAXONOMIC CLASS: Loamy-skeletal, mixed, active, nonacid, thermic Typic Xerofluvents

TYPICAL PEDON: Anderson gravelly loam, grass-forb vegetation (Colors are for dry soil unless otherwise noted.)

A1--0 to 23 inches; Brown (7.5YR 5/3) gravelly loam, dark brown (7.5YR 4/3) moist; massive; hard, friable, nonsticky, nonplastic; many fine roots and pores; moderately acid (pH 6.0); gradual smooth boundary. (10 to 24 inches thick)

C1--23 to 43 inches; Reddish brown (5YR 5/3) very gravelly sandy loam, reddish brown (5YR 4/3) moist massive; hard, friable, nonsticky; few roots and pores; slightly acid (pH 6.2); diffuse boundary. (15 to 30 inches thick)

C2--43 to 60 inches; Reddish brown (5YR 5/3) gravelly sandy loam, reddish brown (5YR 4/3) moist; single grained; loose; slightly acid (pH 6.5).

TYPE LOCATION: Stanislaus County, California; SW 1/4 sec. 17, T. 1 N, R. 11 E.

RANGE IN CHARACTERISTICS: The mean annual soil temperature is about 65 F and the soil temperature is usually not below 47 F at any time. The soil between the depths of 8 and 25 inches is usually is dry all of the time from May or early June until November or early December, and is moist in some or all parts of the rest of the year. Rock fragments in the 10 to 40 section average about 35 to 65 percent. Most pedons have somewhat more fragment in the lower part of the profile than in the upper part. The control section averages sandy loam or light loam. Individual horizons are loam, sandy loam, loamy sand or sand. The profile is stratified and organize matter decreases irregularly with depth and, on the average, is less than 1 percent in the A and C horizons. The profile is slightly or medium acid and for the series as a whole there is nonconsistent pattern of reaction change with depth.

The A horizon is brown to reddish brown (10YR 5/3, 6/4, 7.5YR 5/2, 5/4, 6/4, 5YR 5/3, 5/4).

The C horizon is brown yellowish red (7.5YR 5/4, 5/6, 5/8; 5YR 5/3, 5/4, 5/6, 5/8).

COMPETING SERIES: These are the Cortina, Orland, Soboba, Talmage and Tujunga series. Cortina soils have hue of 10YR or 2.5Y in the C horizons. (See Remarks). Orland soils have less than 35 percent rock fragments and more than 18 percent clay. Soboba soils are sandy. Talmage soils have a mollic epipedon. Tujunga soils are sandy and have less than 35 percent rock fragments.

GEOGRAPHIC SETTING: These Anderson soils usually are nearly level, but include some in colluvium on moderately steep slopes. They are on fans, flood plains and valley footsloped at elevations of 350 to 1,500 feet. They formed in gravelly and cobbly alluvium derived from a wide variety on rock sources. The climate is dry subhumid mesothermal and has warm to hot dry summers and cool moist winter. Mean annual precipitation is 16 to 45 inches. Average January temperature is 45 to 51 F; average July temperature is about 62 F. The freeze-free season is 225 to 300 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Soboba and Tujunga soils and the Bear Creek, Honcut, Perkins, Ramona and Wyman soils. Bear Creek, Perkins, Ramona, and Wyman soils have argillic horizons and less than 35 percent rock fragments. Honcut soils have less than 35 percent rock fragments.

DRAINAGE AND PERMEABILITY: Somewhat excessively drained; slow to medium runoff; moderately rapid permeability. Some lower horizons are coarse textured and rapidly permeable.

USE AND VEGETATION: Used for range and pasture and for growing citrus and avocados. Vegetation in uncultivated areas is annual grasses and forbs, sagebrush, coast live oak, Digger pine and shrubs.

DISTRIBUTION AND EXTENT: Sacramento and Central Valleys and in small; valleys in southern California. The soils are moderately extensive (12,000 acres).


SERIES ESTABLISHED: Shasta County (Redding Area), California, 1907.

REMARKS: The Anderson soils were formerly classified as Alluvial soils. Differentiate between the Cortina and Anderson should be strengthened or the two series should be combined.

The activity class was added to the classification in January of 2003. Competing series were not checked at that time. - ET

Last revised by the state on 6/73.

National Cooperative Soil Survey