LOCATION TEHAMA CA
The Tehama series consists of very deep, well drained soils formed in mixed alluvium. Tehama soils are on fans and terraces and have slopes of 0 to 15 percent. The mean annual precipitation is about 25 inches and the mean annual air temperature is about 62 degrees F.
TAXONOMIC CLASS: Fine-silty, mixed, superactive, thermic Typic Haploxeralfs
TYPICAL PEDON: Tehama silt loam - on a 2 percent south-facing slope in an idle field under annual grasses at 280 feet elevation. (Colors are for dry soil unless otherwise stated).
Ap--0 to 8 inches; pale brown (10YR 6/3) silt loam, brown (10YR 5/3) moist; massive; hard, friable, slightly sticky and slightly plastic; many fine roots; many very fine tubular pores; strongly acid (pH 5.5); abrupt smooth boundary.
A--8 to 19 inches; pale brown (10YR 6/3) silt loam, brown (10YR 5/3) moist, massive; hard, friable, slightly sticky and slightly plastic; common very fine roots in lower part; many very fine tubular pores; moderately acid (pH 5.9); gradual smooth boundary. (Combined thickness of the A horizons 15 to 22 inches).
Bt1--19 to 42 inches; light yellowish brown (2.5Y 6/3) silty clay loam, olive brown (2.5Y 4/3) moist; weak subangular blocky structure; very hard, firm, sticky and plastic; few fine roots; many very fine tubular pores; many thin clay films in pores and common thin clay films on peds; high bulk density; slightly acid (pH 6.5); gradual smooth boundary.
Bt2--42 to 50 inches; light yellowish brown (2.5Y 6/3) loam; olive brown (2.5Y 4/3) moist; massive; very hard, firm, sticky, plastic; few roots; many very fine tubular pores; many thin clay films in pores; neutral (pH 7.1); clear smooth boundary.
Bt3--50 to 60 inches; light yellowish brown (2.5Y 6/3) very gravelly silt loam, olive brown (2.5Y 4/3) moist; massive; hard, very friable, nonsticky and nonplastic; common thin clay films in pores and on rock fragments; slightly alkaline (pH 7.5). (Combined thickness of the Bt horizons is 25 to 45 inches).
TYPE LOCATION: Tehama County, California; about 1 mile northwest of Corning Southern Pacific Railroad depot, 1,200 feet west and 200 feet south from the NE corner of sec. 15, T. 24 N., R. 3 W., Corning Quadrangle 7.5 minute series.
RANGE IN CHARACTERISTICS: Thickness of the solum is over 60 inches. The mean annual soil temperature is 62 to 66 degrees F and exceeds 41 degrees F all year. The soil between the depths of 7 and 21 inches is dry in all parts from June to October and is moist in some part the rest of the year. The particle-size control section averages 30 percent clay and has a range of 11 to 15 percent fine sand or coarser, including fragments up to 7.5 cm in diameter.
The A horizon is 10YR 6/2, 6/3, 6/4; 2.5Y 6/2, or 6/4 dry. Moist colors are 10YR 5/3, 4/4, 4/3, 4/2; 2.5Y 4/2, or 4/4. Texture is silt loam, loam, or fine sandy loam. Reaction is strongly acid to slightly acid.
The upper Bt horizon is 10YR 6/3, 6/4, 5/2, 5/3; 2.5Y 6/3, 5/2, 5/4, 4/2, or 4/4 dry. Moist colors are 10YR 4/3, 4/4; 2.5Y 4/2, 4/3 or 4/4. Texture is silty clay loam, clay loam or loam, and contains about 10 to 15 percent more clay than the A horizon. Reaction ranges from slightly acid to neutral.
The lower Bt horizon colors are 10YR 6/3, 6/4; 2.5Y 6/3, 6/4, or 6/6 dry. Moist colors are 10YR 4/2, 4/3; 2.5Y 4/2, 4/3, or 4/4. Textures are clay loam, silty clay loam or stratified very gravelly loam, very gravelly silt loam and very gravelly sandy loam. Reaction ranges from neutral to mildly alkaline. Some pedons have a perched water table at 36 to 50 inches from December through March.
COMPETING SERIES: These are the
Kreyenhagen series in the same family and the
Arbuckle series. Kreyenhagen soils have a paralithic contact within 60 inches; (solum thickness 60 inches or less) and have 50 to 75 percent slopes. Arbuckle soils have a fine-loamy control section.
GEOGRAPHIC SETTING: The Tehama soils are on terraces and fans and have slopes of 0 to 15 percent. The soils formed in mixed alluvium. Elevations are 50 to 2170 feet. The climate is Mediterranean with hot dry summers and cool moist winters. Mean annual precipitation varies from 15 to 41 inches. Mean January temperature is about 45 degrees F; mean July temperature is about 80 degrees F; mean annual air temperature is about 62 degrees F. Frost-free season ranges from 250 to 280 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Red Bluff soils. Corning soils are on slightly higher old terraces and have clay subsoil. Redding soils are on higher old terraces and have a duripan within 20 inches. Red Bluff soils have clayey, strongly acid subsoil.
DRAINAGE AND PERMEABILITY: Well drained or moderately well drained; medium runoff; slow permeability.
USE AND VEGETATION: Small grains and pasture are grown where this soil is dry farmed. Row crops, pasture and a few orchards are grown under irrigation.
DISTRIBUTION AND EXTENT: Sacramento Valley, California. Tehama soils are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Tehama County, California, 1910.
REMARKS: Laboratory data by University of California, Davis was used to verify classification.
The activity class was added to the classification in January of 2003. Competing series were not checked at that time. - ET
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - extends from 0 to 19 inches. Argillic horizon extends from 19 to 50 inches. Control section which begins at 19 inches to 39 inches has an average of 30 percent clay and 12 percent fine sand or coarser including fragments up to 7.5 cm in diameter by weight.
National Cooperative Soil Survey