Established Series


The Bear Creek series consists of moderately well to somewhat poorly (imperfectly) drained (minimal) Noncalcic Brown soils having some Humic Gley characteristics and developed from medium textured mixed alluvium. They occur on nearly level narrow alluvial fans and floodplains under annual grass-herb vegetation. The parent material originated from a wide range of rock materials but in most places includes some material from basic igneous rocks. Slopes are 0 to 5 percent.

TAXONOMIC CLASS: Fine-loamy, mixed, superactive, thermic Typic Endoaqualfs

TYPICAL PEDON: Bear Creek loam (range pasture)

A1--0 to 15 inches; dark gray (10YR 4/1) loam, very dark gray, (10YR 3/1) moist; essentially massive when dry; weak fine granular structure moist; hard, friable, plastic and sticky; contains a little gravel; moderately low in organic matter; numerous fine roots and pores; many worm and insect burrows; slightly acid, pH increasing with depth (pH 6.1 to 6.4); clear wavy boundary. (10 to 20 inches thick).

B2g--15 to 30 inches; grayish brown (10YR 5/2) heavy loam or light clay loam, dark grayish brown (10YR 4/2) when moist with distinct common medium mottles of strong brown (7.5YR 5/6) in the lower part; moderate medium blocky structure; firm, plastic and sticky; thin patchy clay films of dark gray (10YR 4/1) or very dark gray, (10YR 3/1); few scattered gravels; numerous fine roots; some insect and worm burrows; slightly acid (pH 6.4); abrupt smooth boundary. (15 to 30 inches thick).

D--30 inches +; grayish brown and bluish gray, hard, andesitic tuff rock unrelated to the profile above.

TYPE LOCATION: Merced County, California; 1/8 mile west of Southeast corner, sec. 27, T. 7S., R. 16E., along Cunningham Road.

RANGE IN CHARACTERISTICS: The reaction changes with depth from slightly acid in the A1 horizon to neutral or slightly alkaline below the B2 horizon. From little to large amounts of gravelly material are present in the profile.

Color of the A1 horizon ranges from dark gray (10YR 4/1) to dark grayish brown (10YR 4/2) but may be grayish brown (10YR 5/2) in coarser textured types.

The B2 horizon ranges from dark gray (10YR 4/1) to grayish brown (10YR 5/2). The depth to the unrelated substratum is quite variable, generally being 6 feet or less and commonly 3 to 4 1/2 feet.

Deeper profiles have a C horizon above the D of about the same color as the B2 horizon or browner (7.5YR 4/2). It is usually mottled strong brown (7.5YR 5/6) or yellowish brown (10YR 5/4).


GEOGRAPHIC SETTING: The Bear Creek soils occur at elevations from 100 to 300 feet in a dry subhumid, mesothermal climate having a mean annual precipitation of 12 to 18 inches with hot, dry summers and cool, moist winters; an average January temperature of 44 degrees F., an average July temperature of 78 degrees F. with a mean annual temperature of 60 degrees F. and an average frost free season of about 270 days.

GEOGRAPHICALLY ASSOCIATED SOILS: The Bear Creek soils occur in the same general area as the Cometa, Redding, Rocklin, San Joaquin and Whitney series. They resemble the Landlow, Marquerite and Paulsell soils in some respects. The Landlow soils are developed in the basic alluvium, are moderately fine or fine textured throughout, and are lime cemented in the upper C horizon. The Marquerite soils are very deep, well drained (minimal) Noncalcic Brown soils developed in medium textured alluvium from sedimentary rock sources. They are not mottled in the B2 horizons. The Paulsell soils are deep imperfectly drained Humic Gley soils developed in dominantly basic alluvium. The sola are fine textured with some grumosolic characteristics.

DRAINAGE AND PERMEABILITY: Moderately well to somewhat poorly drained; low to very low run off,

USE AND VEGETATION: These soils are usually in grass, although a few of the wider, larger bodies are irrigated and planted to Ladino clover or a dry-farmed to barley. Both grass and grain grow well on these soils, but due to the fact that most areas are narrow and cut by stream courses, the soils are best adapted to pasture in associated with the adjacent range land. Grasses and herbaceous annuals, with some willows along stream banks. Vegetation is relatively dense.

DISTRIBUTION AND EXTENT: The Bear Creek series is mapped along the eastern side of the Central Valley in California where it is not extensive. Small, narrow valleys in the lower western foothills of the Sierra Nevada Mountains.


SERIES ESTABLISHED: Lodi area, California, 1932. (Source of name is Bear Creek in San Joaquin County.)

REMARKS: Soils classified in the Bear Creek series in the Napa Area, California have more distinct horizonation and more clayey B2 horizons than now permitted in the series. Some the soils classified in the Bear Creek series in the Lodi Area are poorly drained clays which would also be excluded at the present time.

The classification was updated in February 2001 using the Eighth Edition to Soil Taxonomy. This series was formerly classified as fine-loamy, mixed, thermic Aeric Ochraqualfs. Competing series were not checked at that time.

OSED scanned by SSQA. Last major revision by state on 1/59.

National Cooperative Soil Survey