LOCATION TUSCAN CAEstablished Series
TAXONOMIC CLASS: Clayey, smectitic, thermic, shallow Typic Durixeralfs
TYPICAL PEDON: Tuscan cobbly loam (range-pasture) (Colors for dry conditions unless otherwise noted).
A11--0 to 3 inches; Dark brown (7.5YR 4/3) cobbly loam dark reddish brown (5YR 3/3) moist; nearly massive when dry breaking readily to weak fine granular structure; slightly hard, friable, slightly sticky, slightly plastic; abundant very fine roots; many very fine pores; slightly acid; abrupt wavy boundary. 1 to 3 inches thick.
A12--3 to 7 inches; Reddish brown (5YR 4/3) cobbly loam, dark reddish brown (5YR 3/3) moist; strong very fine subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic; abundant very fine roots; many very fine pores; slightly acid; clear irregular boundary. 3 to 6 inches thick.
B1t--7 to 10 inches; Reddish brown (5YR 4/4) cobbly light clay loam, dark reddish brown (5YR 3/4) moist; moderate medium to very fine subangular blocky structure; hard, firm, sticky and slightly plastic; thin continuous clay films in pores, colloid mainly in bridges; few very fine roots; many very fine pores; slightly acid; abrupt wavy boundary. 2 to 4 inches thick.
B2t--10 to 17 inches; Reddish brown (5YR 4/4) cobbly clay, dark reddish brown (5YR 3/4) moist; massive; hard, firm, sticky and plastic; few very fine roots; common very fine tubular pores; moderately thick continuous clay films on some ped faces, in all pores, and in bridges; medium acid less acid with increasing depth; abrupt wavy boundary. 2 to 8 inches thick.
C1m--17 to 18 inches; Reddish brown (5YR 5/4) indurated cobbly hardpan, dark reddish brown (5YR 3/4) moist with some thin silica coatings on pebbles and cobbles and black manganese stains in seams; massive; extremely hard; (clay films are visible and apparently this horizon had considerable clay accumulation before becoming cemented); abrupt wavy boundary. 1 to 2 inches thick.
C2m--18 inches+; Cemented stratified cobbles and gravels of basic igneous origin.
TYPE LOCATION: Tehama County, California, in the SW1/4 of the NW1/4 of Sec. 29, T.27N, R.2W, 3 miles east of Dairyville on Foothill Road.
RANGE IN CHARACTERISTICS: Thickness of solum usually is less than 20 inches but ranges from 8 to 24 inches. The A horizons contain < 1 percent organic matter. The A1 horizons range in color from grayish brown (10YR) brown and dark brown (7.5YR) to reddish brown and yellowish red (5YR) in lower part; in texture from gravelly or cobbly loam to cobbly light clay loam; in structure from massive to granular; in reaction from slightly acid to strongly acid. The B2t horizon ranges in color from brown and dark brown (7.5YR) to reddish brown (5YR) and dark reddish brown to dark red (2.5YR); in texture from gravelly or cobbly heavy clay loam to gravelly clay, occasionally very gravelly clay; in structure from massive to strong prismatic or angular blocky; in reaction from medium acid to neutral (pH 6.0-7.0). Most profiles have a B1 horizon; these range from 2 to 7 inches thick.
COMPETING SERIES: These include the Clough, Gloria, Igo, Moda, Palo Cedro, Redding, San Joaquin and Yokohl series. The Clough soils have abrupt AB boundaries and very gravelly, very strongly acid Bt horizons. The Gloria soils are moderately deep or deep to the duripan. The Igo soils lack argillic horizons. The Moda soils have abrupt AB boundaries and are brown or light brown. The Palo Cedro soils are brown, have abrupt AB boundaries and strongly acid Bt horizons. The Redding soils are kaolinitic, have abrupt AB boundaries and medium to strongly acid Bt horizons. The San Joaquin soils have A1 horizons with pale colors (values 4 or more moist) and abrupt AB boundaries. Yokohl soils have abrupt AB boundaries.
GEOGRAPHIC SETTING: The Tuscan soils occur on broad gently sloping old alluvial terraces that are hummocky or gently undulating. The alluvium was derived mostly from basalt, andesite and tuff. The soils occur at elevations of 200 to 1,000 feet in a subhumid climate with mean annual rainfall of 20 to 35 inches, with hot dry summers and cool moist winters. Mean annual temperature is about 60 degrees F., average January temperature about 45 degrees F., and average July temperature about 75 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: The Tuscan soils occur in the same general area as the Anita, Igo, Inks, Keefers, Redding and Supan soils.
DRAINAGE AND PERMEABILITY: Well drained, permeability moderate over slow and very slow, slow to medium runoff.
USE AND VEGETATION: Winter and spring range. Natural vegetation is annual grasses and forbs with a thin layer of moss in open areas.
DISTRIBUTION AND EXTENT: Eastern margin of Sacramento Valley and small scattered areas in central coastal counties, California.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Soil survey of Red Bluff Area, Tehama County, California, 1910.
REMARKS: The Tuscan series was formerly classified in the (maximal) Noncalcic Brown group. The soils have an argillic horizon and a duripan.
OSED scanned by SSQA. Last revised by state on 12/16/65.