LOCATION DIBBLE CA
The Dibble series consists of moderately deep, well drained soils that formed in material weathered from shale, sandstone and semi consolidated densic material. Dibble soils are on foothills and fan remnants and have slopes of 2 to 75 percent. The mean annual precipitation is about 25 inches and the mean annual air temperature is about 63 degrees F.
TAXONOMIC CLASS: Fine, smectitic, thermic Typic Haploxeralfs
TYPICAL PEDON: Dibble silt loam - rangeland. (Colors are for dry soil unless otherwise stated.)
A1--0 to 2 inches (0 to 5 cm); pale brown (10YR 6/3) silt loam, olive brown (2.5Y 4/4) moist; weak medium platy structure; very hard, friable, slightly sticky and slightly plastic; many very fine roots; many very fine pores; moderately acid (pH 5.8); abrupt smooth boundary. (1 to 4 inches thick)
A2--2 to 6 inches (5 to 15 cm); pale brown (10YR 6/3) light clay loam, brown (10YR 4/3) moist; massive; hard, friable, slightly sticky and plastic; common very fine roots; many very fine pores; moderately acid (pH 5.8); clear wavy boundary. (3 to 13 inches thick)
BAt--6 to 9 inches (15 to 23 cm); pale brown (10YR 6/3) heavy clay loam, yellowish brown (10YR 5/4) moist; massive; hard, friable, slightly sticky and plastic; common very fine roots; many very fine pores; few thin clay films lining pores; moderately acid (pH 5.8); gradual irregular boundary. (2 to 4 inches thick)
Bt1--9 to 17 inches (23 to 43 cm); pale brown (10YR 6/3) clay, yellowish brown (10YR 5/4) moist; moderate coarse subangular blocky structure; hard, firm, very sticky and very plastic; few very fine roots; few very fine pores; moderately thick continuous clay films along root channels, bridging mineral grains and lining pores; moderately acid (pH 5.8); gradual irregular boundary. (4 to 10 inches thick)
Bt2--17 to 24 inches (43 to 61 cm); light yellowish brown (10YR 6/4) heavy clay loam, yellowish brown (10YR 5/4) moist; massive; hard, firm, very sticky and very plastic; few very fine roots; few very fine pores; thin continuous clay films along root channels, bridging mineral grains and lining pores; moderately acid (pH 5.8); gradual irregular boundary. (5 to 10 inches thick)
BCt--24 to 34 inches (61 to 86 cm); yellow (10YR 7/6) heavy clay loam, yellowish brown (10YR 5/6) moist; massive; slightly hard, firm, sticky and plastic; few roots; few very fine pores; thin clay films line larger root channels; moderately acid (pH 5.7); abrupt wavy boundary. (5 to 10 inches thick)
Cd--34 to 40 inches (86 to 102 cm); yellow (10YR 8/8) silt loam; compact, massive, hard and brittle; moderately acid (pH 5.9); can be carved with knife.
TYPE LOCATION: Tehama County, California; about 15 miles west of Red Bluff on Masten Road, 1/4 mile south of Reeds Creek Road in the SW corner of the NE1/4 SE1/4 of sec. 23, T. 27 N., R. 6 W. 40 degrees 10 minutes 47 seconds North, 122 degrees 30 minutes 18.3 seconds West, NAD83
RANGE IN CHARACTERISTICS: Depth to a paralithic or densic contact of sedimentary rock or densic material is 20 to 40 inches. The mean annual soil temperature is about 62 to 65 degrees F. and the soil temperature is above 47 degrees F. except for brief periods in January. The soils usually are moist all of the time in some or all parts between depths of 4 to 12 inches from about November until about May and usually are dry the rest of the time.
The A horizon is 10YR 6/2, 6/3, 6/4, 5/3, 5/4; 2.5Y.5/4, 6/4. Moist value is 4 or more. It is loam, silt loam, clay loam or silty clay loam. Many pedons are massive, but structure is weak platy or subangular blocky in some pedons. This horizon is hard or very hard and is neutral to medium acid. The boundary between the A horizon and the Bt horizon is clear or gradual or a transitional horizon is present.
The Bt horizon is 10YR 5/3, 5/4, 4/4, 6/3, 6/4, 6/6, 7/6; 2.5Y 6/ or 5/4. Moist value is dominantly one or two units darker than the dry value. This horizon is heavy clay loam, silty clay loam, silty clay or clay and has 35 to 45 percent clay and 15 to 20 percent material coarser than very fine sand. It is massive or has weak to moderate subangular blocky or prismatic structure. The horizon is neutral to medium acid.
COMPETING SERIES: These are the
Stomar series. Los Banos soils have 5YR hue in the Bt horizons and are deeper than 40 inches to paralithic contact. Stomar and Ryer soils lack a paralithic contact.
GEOGRAPHIC SETTING: Dibble soils are on undulating gentle to very steep fan remnants and hills and have slopes of 2 to 75 percent. They formed in material weathered from silty densic material, shale or sandstone. Elevations are 100 to 2,500 feet. The climate is subhumid with hot dry summers and cool moist winters. Mean annual precipitation is 16 to 40 inches. Mean annual temperature is about 60 to 65 degrees F.; average January temperature is about 43 degrees F.; average July temperature is about 77 degrees F. Freeze-free season is about 150 to 270 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Redding soils. Los Osos soils have mollic epipedons. Gazos and Laughlin soils have mollic epipedons and lack argillic horizons. Newville soils have abrupt E-Bt horizon boundaries with more than 15 percent increase in clay content. Redding soils have a reddish silica-cemented duripan.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; slow permeability.
USE AND VEGETATION: Used for grazing. Vegetation is annual grasses and oaks.
DISTRIBUTION AND EXTENT: West side of Sacramento Valley southward in the Coast Range of California. The soils are of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Tehama County, California 1961.
OSED scanned by SSQA. Last revised by state on 11/83.
Edits made after sdjr projects and reassessment of OSD profile characteristics and setting in MLRA 17 on the Tehama Formation. OSD setting is different than where mapped in MLRA 15 over Coast Range bedrock. - AEC
National Cooperative Soil Survey