LOCATION POZO               CA 
Established Series
RU/RJA/JEM/ET
03/2001

POZO SERIES


The Pozo series consists of Humic Gley soils without textural B horizons but having prominent hardpans and developed from medium and moderately fine textured alluvium largely from granitic source. They occur on nearly level slopes in basin areas under annual grass-forb and saline alkali grass and shrub vegetation. The Pozo soils characteristically have dark gray, noncalcareous, and moderate in organic matter in the A horizon overlying nearly white calcareous upper C horizons and strongly lime silica cemented hardpans at moderate depths. Excess salts, alkali, or both are typically found in the profile.

TAXONOMIC CLASS: Fine-loamy, mixed, superactive, thermic Cambidic Durixerolls

TYPICAL PEDON: Pozo loam (range pasture).

A1--0 to 11 inches; dark gray (10YR 4/1) loam; black (10YR 2/1) moist; weak very fine granular structure; hard, friable, slightly plastic and nonsticky; moderate organic matter content; numerous fine roots and pores; neutral (pH 7.2); abrupt smooth boundary. 4 to 11 inches thick.

C1--11 to 22 inches; white (10YR 8/1) heavy loam; light brownish gray (2.5Y 6/2) moist; massive; hard, friable, nonplastic and nonsticky; numerous fine pores; moderately alkaline (pH 7.9); moderately calcareous; very abrupt smooth boundary. 10 to 15 inches thick.

Cmca--22 to 24 inches; thin white (10YR 8/1), seams alternating with thicker seams of light gray (10YR 7/2) strongly cemented lime-silica hardpan; grayish brown (2.5Y 5\2) when moist; moderately calcareous; abrupt smooth boundary. 1 to 3 inches thick.

C2--24 to 36 inches +; white (10YR 8/2) fine sandy loam; light brownish gray (2.5Y 6/2) moist; massive; hard, friable; nonplastic and nonsticky; moderately alkaline (pH 8.1); strongly calcareous.

TYPE LOCATION: Madera County, California, SW 1/4 Sec. 8, T. 11 S., R. 14 E.

RANGE IN CHARACTERISTICS: The A1 horizon color may be gray (10YR 5/1) to dark gray (10YR 4/1) and the thickness is variable. Textures of the A1 horizon are medium and moderately fine, mainly silt loams and clay loams. In the case of leveled and farmed ares, the A1 horizon may be entirely removed. The hardpan layer is variable as to depth, thickness, and hardiness. Several successive hardpan layers alternating with more friable material may occur.

COMPETING SERIES: Competing series were not generated when this series was entered into the Ames database.

GEOGRAPHIC SETTING: Nearly level basin areas cut by occasional steep-sided drainage channels. The Pozo soils occur at elevations of 100 to 150 feet in a semiarid mesothermal climate having a mean annual precipitation of 8 to 9 inches with hot, dry summers and cool moist winters; an average January temperature of 45 degrees F.; and average July temperature of 82 degrees F. with a mean annual temperature of 63 degrees F., and an average frost free season of 250 to 280 days. The Pozo series is mapped in the basin area along the east side of the San Joaquin River, California.

GEOGRAPHICALLY ASSOCIATED SOILS: The Pozo soils occur in the same general area as the Columbia, El Peco, Fresno, Merced, Rossi and Temple soils, and they most nearly resemble the El Peco and Fresno series. The El Peco soils have very pale brown surface layers low in organic matter, but the profiles are otherwise similar to those of the Pozo series. The Fresno soils have surface soil characteristics similar to those of the El Peco series but have moderately developed B horizons.

DRAINAGE AND PERMEABILITY: Probably poor to somewhat poor (imperfect) under natural conditions. Pumping has altered the natural drainage considerably and most areas are now somewhat poorly (imperfectly) drained; very slow to slow surface runoff and very slow permeability. The water table is now well below the profile and no longer has any effect on the soil in most places.

USE AND VEGETATION: Mainly for range pasture, some areas have been leveled and planted to irrigated crops such as cotton, barley and pasture. Most areas are thickly covered with Lippia, annual grasses, herbs, saltgrass and sacation.

DISTRIBUTION AND EXTENT: Basin areas on east side of San Joaquin River floodplain, central San Joaquin Valley, California.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California

SERIES ESTABLISHED: Merced Area, California, 1953, (Source of name is Pozo Farms, Madera County.)

REMARKS: OSED scanned by SSQA. The classification was updated in February 2001 using the Eighth Edition to Soil Taxonomy. This series was formerly classified as fine-loamy, mixed, thermic Orthidic Durixerolls. Competing series were not checked at that time. Last major revision by state on 1/59.

ADDITIONAL DATA: NSSL Pedon (Pozo taxadjunct) S58CA-039-001.


National Cooperative Soil Survey
U.S.A.