LOCATION KEEFERS CAEstablished Series
TAXONOMIC CLASS: Clayey-skeletal, smectitic, thermic Mollic Haploxeralfs
TYPICAL PEDON: Keefers gravelly loam - rangeland. (Colors for dry soils unless otherwise stated.)
A11--0 to 2 inches; grayish brown (10YR 5/2) gravelly loam, dark brown (10YR 3/3) moist with common fine yellowish red (5YR 3/6) flecks; weak medium platy structure; slightly hard, friable, slightly plastic and slightly sticky; many very fine roots; many very fine pores; slightly acid (pH 6.5); abrupt, smooth boundary. (1 to 3 inches thick)
A12--2 to 8 inches; brown (7.5YR 5/3) gravelly loam, dark brown (7.5YR 3/3) moist; massive; hard, friable, slightly sticky, slightly plastic; many very fine roots; many very fine pores; few black and red shot about 1 mm. in diameter; slightly acid (pH 6.5); clear smooth boundary. (4 to 8 inches thick)
A3--8 to 14 inches; brown (7.5YR 5/3) slightly gravelly loam, dark brown (7.5YR 3/3) moist; massive; hard, friable, slightly sticky, slightly plastic; many very fine roots; common very fine and fine pores; slightly acid (pH 6.5); clear smooth boundary. (5 to 10 inches thick)
B1--14 to 20 inches; brown (7.5YR 4/3) gritty clay loam, dark reddish brown (5YR 3/3) moist; massive, hard, friable, slightly sticky, slightly plastic; many very fine pores; colloid mainly in bridges, no clay films; slightly acid (pH 6.5); abrupt smooth boundary. (4 to 8 inches thick)
IIB2t--20 to 45 inches; reddish brown (5YR 4/3) very cobbly clay becoming slightly less cobbly in the lower portion, dark reddish brown (5YR 3/4) moist; massive; very hard, firm, very plastic and very sticky; few very fine roots; common very fine and fine tubular pores, irregular shaped cavities up to 10 mm. diameter are between cobbles; moderately thick continuous clay films in pores; neutral (pH 7.0); gradual smooth boundary. (20 to 30 inches thick)
IIB3t--45 to 55 inches; brown (7.5YR 5/4) very cobbly sandy clay, dark reddish brown (5YR 3/3) moist; massive; hard, firm, very plastic, and very sticky; very few very fine roots; common very fire interstitial pores; moderately thick clay films on gravels and cobbles and in pores, a few cobbles are surrounded by clay layers 1/8 to 1/4 inch thick; most cobbles have black Mn coating on surfaces and along fracture planes; ground water probably moves laterally through this horizon; neutral.
TYPE LOCATION: Butte County, California about 6 miles northwest of Oroville, near the center of the SE1/4 of the NE1/4 of Section 10, T.20N., R.3E.
RANGE IN CHARACTERISTICS: Solum thickness is about 4 to 6 feet and very cobbly layers are at 18 to 29 inches. In some pedons there are indurated substrata below 40 inches. Soil temperature is 61 to 65 degrees F. The soils are dry in the moisture control section most years from about June 5 to the end of September. The remainder of the year, the soils are moist. The A horizons have colors in 10YR and 7.5YR hues with values of 4 or 5 dry and 3 moist. Chromas are 2 or 3. Texture is gravelly or cobbly loam, structure is weak or massive, and consistence is hard or slightly hard, friable, slightly sticky and slightly plastic. Reaction is slightly acid to medium acid. The B2t horizons have colors in 7.5YR to 2.5YR. hues, values of 4 to 6 dry and 3 or 4 moist. Chromas are 3 or 4. Texture is clay or sandy clay and there is more than 50 percent by volume of coarse fragments which usually are cobbles or gravels. Structure is massive and consistence is hard or very hard, firm, very plastic and very sticky. Reaction is slightly acid to neutral.
COMPETING SERIES: Corning, Gloria, Perkins, Red Bluff, Ryer, Tuscan and Yokohl series are similar. Corning soils have red strongly acid B2t horizons and yellowish red A horizons. Gloria, Yokohl, and Tuscan soils have duripans near 20 inches in depth. Perkins soils have yellowish red B2t horizons that have less than 50 percent gravels and Red Bluff soils have strongly acid red, nongravelly B2t horizons. Ryer soils have brown heavy clay loam B2t horizons that are weakly calcareous in the lower part.
GEOGRAPHIC SETTING: Keefers soils occur on gently sloping to undulating old terraces that were derived mainly from basic igneous rocks. They occur at elevations of 200 to 1,000 feet, in a moist subhumid mesothermal climate with mean annual rainfall of 23 to 40 inches, with hot, dry summers and cool, moist winters. Mean annual temperature is about 62 degrees F., average January temperature about 45 degrees F., and average July temperature about 82 degrees F. Frost-free season averages about 230 to 280 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are dark gray Anita soils with hardpans, clayey Berrendos soils, Redding soils with hardpans, and Red Bluff and Tuscan soils.
DRAINAGE AND PERMEABILITY: Well drained with slow permeability and moderately rapid to rapid runoff.
USE AND VEGETATION: Used mainly for range pasture. Vegetation is annual grasses and forbs with scattered oaks and shrubs.
DISTRIBUTION AND EXTENT: Eastern margin of the Sacramento Valley. The soils are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Chico area, Butte County, California, 1925.
REMARKS: The Keefers series formerly was classified in the Noncalcic Brown great soil group.
OSED scanned by SSQA. Last revised by state on 11/69.