LOCATION COLE               CA
Established Series
Rev. DWS-JMK-DJE-ET
02/2003

COLE SERIES


The Cole series consists of very deep, somewhat poorly drained soils that formed in alluvium from mixed sources. Cole soils are on river tarraces, basins, flood plains, or on alluvial fans with slopes of 0 to 5 percent. The mean annual precipitation is about 40 inches and the mean annual air temperature is about 60 degrees F.

TAXONOMIC CLASS: Fine, mixed, superactive, thermic Pachic Argixerolls

TYPICAL PEDON: Cole clay loam - on a 1 percent slope in an irrigated walnut orchard at 1,360 feet. (Colors are for dry soil unless otherwise noted. When described on April 28, 1976, the soil was slightly moist throughout).

Ap--0 to 6 inches; grayish brown (10YR 5/2) clay loam, very dark grayish brown (10YR 3/2) moist; moderate fine and medium subangular blocky structure parting to strong fine and medium granular; hard, firm, sticky and plastic; common very fine, fine and medium roots; common fine and medium tubular pores; few worm casts; slightly acid (pH 6.5); abrupt smooth boundary. (6 to 15 inches thick)

BAt--6 to 13 inches; grayish brown (10YR 5/2) clay loam, very dark gray (10YR 3/1) moist; moderate fine and medium subangular blocky structure parting to strong fine and medium granular; hard, firm, sticky and plastic; common very fine, fine and medium roots; many fine and medium tubular pores; common thin clay films on peds and in pores; few worm casts; slightly acid (pH 6.3); clear smooth boundary. (0 to 8 inches thick)

Bt1--13 to 35 inches; gray (10YR 5/1) clay loam, very dark grayish brown (10YR 3/2) moist; weak medium and coarse angular blocky structure; very hard, firm, sticky and plastic; common very fine, fine and medium roots; common very fine and fine and few medium tubular pores; many thin and common moderately thick clay films on peds and in pores; 2 percent pebbles 5 to 15 mm in diameter; moderately alkaline (pH 8.0); clear wavy boundary. (10 to 22 inches thick)

Bt2--35 to 51 inches; brownish yellow (10YR 6/6) clay loam, yellowish brown (10YR 5/4) moist; grayish brown (10YR 5/2) clay films on peds and in pores; dark grayish brown (10YR 4/2) moist; weak medium prismatic structure; hard, firm, sticky and plastic; common medium coarse and few fine roots; common very fine, fine and few medium tubular pores; many thin clay films bridging mineral grains and common moderately thick clay films on peds and in pores; moderately alkaline (pH 8.0); clear wavy boundary. (6 to 17 inches thick).

BCt--51 to 62 inches; variegated brown (10YR 5/3) and pale brown (10YR 6/3) clay loam, yellowish brown (10YR 5/4) moist; grayish brown (10YR 5/2) clay films; weak medium prismatic structure; hard, firm, sticky and plastic; common medium, coarse and few fine roots; many very fine, fine and common medium tubular pores; few thin and moderately thick clay films bridging mineral grains, on peds, and in pores; moderately alkaline (pH 8.0); clear smooth boundary. (0 to 15 inches thick)

C--62 to 71 inches; variegated brown (10YR 5/3) and pale brown (10YR 6/3) clay loam, yellowish brown (10YR 5/4) moist; grayish brown (10YR 5/2) clay films; weak medium prismatic structure; hard, firm, sticky and plastic; few fine and medium roots; common very fine, fine and few medium tubular pores; common thin clay films on peds, bridging mineral grains and in pores; 4 percent pebbles 2 to 20 mm in diameter; moderately alkaline (pH 8.0).

TYPE LOCATION: Lake County, California; about 5 miles southeast of Lakeport, 75 feet northwest of the junction of Argonaut Road and Thomas Drive; NE1/4 NE1/4, section 8, T.13 N., R.9 W.

RANGE IN CHARACTERISTICS: The mean annual soil temperature is 59 to 65 degrees F, and the soil temperature usually is not below 47 degrees at any time. The soil between depths of 4 and 12 inches is usually dry from July 1 to October 1 and is moist in all parts from December 1 to April 30. The soils usually increase in alkalinity with increasing depth but are noncalcareous. The particle-size control section has 35 to 45 percent clay. Organic carbon is 1 to 2 percent to a depth of 20 to 35 inches. Gravel content ranges from 0 to 15 percent throughout.

The A horizon dry color is 10YR 3/2, 4/1, 4/2, 4/3, 5/1, 5/2, 5/3; 2.5Y 4/1, 4/2, 5/1 or 5/2. Moist colors are 10YR 2/1, 2/2, 3/1, 3/2, 3/3; or 2.5Y 3/2. It is loam, silt loam, clay loam, or silty clay loam and has granular or subangular blocky structure. It is slightly hard to very hard and is neutral to moderately acid. Some pedons have A3 horizons, B1 horizons or Blt horizons.

The Bt horizon dry color is 10YR 2/1, 2/2, 3/1, 3/2, 4/1, 4/2, 4/3, 5/1, 5/2, 5/3, 5/4, 6/3; 2.5Y 3/2, 4/2, 5/2 N 3/0, or N 4/0. Moist colors are 10YR 2/1, 2/2, 3/1, 3/2, 3/3, 4/1, 4/2, 4/3 4/4; 2.5Y 3/2, 4/2 or 5/2. In some pedons the lower part has dry colors of 10YR 6/2, 6/3, 6/4 or 6/6. Moist colors are 4/4, 5/3 or 5/4 and some also have mottles. It is silty clay loam, clay loam, silty clay or clay and averages 35 to 50 percent clay in the upper 20 inches. It is slightly acid to moderately alkaline.

The C horizon dry color has hues of 10YR, 2.5Y or 5Y and values 3 through 6 dry and 2 through 6 moist. Chroma is 1 through 3 dry and 2 through 4 moist. It is clay loam, clay loam, silty clay loam or clay and is mildly or moderately alkaline. Some pedons are underlain by gravel.

COMPETING SERIES: There are no other series in this family.

GEOGRAPHIC SETTING: Cole soils are on flood plains and fans and in basins at elevations of 50 to 1,500 feet. Slopes are 0 to 5 percent. The soils formed in alluvium from mixed sources. The climate is subhumid with warm or hot dry summers and cool moist winters. Mean annual precipitation is 25 to 50 inches. Average January temperature is 55 to 61 degrees F. The frost-free period is 150 to 290 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bale, Botella, Soquel, Clear Lake, Cortina, Pajaro, and Yolo soils. Clear Lake soils are clayey throughout and have intersecting slickensides. Cortina soils have an ochric epipedon and have a loamy-skeletal control section. Pajaro soils lack an argillic horizon, have a fine-loamy control section, and have an aquic moisture regime. Yolo soils have an ochric epipedon, lack an argillic horizon, and have a fine-silty control section.

DRAINAGE AND PERMEABILITY: Somewhat poorly drained; slow runoff; slow permeability. Many areas have been artificially drained or have drainage altered by gullying.

USE AND VEGETATION: Used mostly for production of orchards, vineyards, truck crops, and irrigated pasture. Uncultivated areas have oak-grass vegetation with some shrubs and forbs.

DISTRIBUTION AND EXTENT: North coastal counties, California. The soils are moderately extensive. MLRA is 14.

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

SERIES ESTABLISHED: Lake County, California. Clear Lake Area 1927.

REMARKS: The activity class was added to the classification in February of 2003. Competing series were not checked at that time. - ET

Diagnostic horizons and features recognized in this pedon are:

Mollic Pachic epipedon -- the zone from 0 to 35 inches (Ap, BAt, Bt1)

Argillic horizon -- the zone from 6 to 62 inches (BAt, Bt1, Bt2, Bct)


National Cooperative Soil Survey
U.S.A.