LOCATION CORBIERE CAEstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, thermic Cumulic Vertic Endoaquolls
TYPICAL PEDON: Corbiere silt loam-- on a cultivated nearly level south facing slope of 1 percent at an elevation of 35 feet. When described (10/25/88) the soil was dry to 20 inches and moist below. (Colors are for dry soil unless otherwise stated)
Ap--0 to 7 inches; grayish brown (10YR 5/2) silt loam, very dark grayish brown (10YR 3/2) moist; moderate medium subangular blocky structure; hard, friable, sticky and plastic; many very fine and few fine roots; common fine interstitial pores; strongly effervescent with disseminated lime; neutral (pH 7.3); clear smooth boundary.
Bw1--7 to 14 inches; grayish brown (10YR 5/2) silt loam, very dark grayish brown (10YR 3/2) moist; moderate medium subangular blocky structure; hard, friable, sticky and plastic; common very fine roots; common very fine tubular pores; strongly effervescent with disseminated lime; few, fine, prominent very dark grayish brown (2.5Y 3/2) moist redoximorphic concentrations; slightly alkaline (pH 7.4); clear smooth boundary.
Bw2--14 to 22 inches; brown (10YR 5/3) silty clay loam, dark brown (10YR 3/3) moist; moderate fine subangular blocky structure; hard, firm, sticky and slightly plastic; few very fine roots; common very fine tubular pores; strongly effervescent with disseminated lime; common, fine, prominent very dark grayish brown (2.5Y 3/2) moist redoximorphic concentrations; neutral (pH 7.3); gradual smooth boundary.
2Bw--22 to 35 inches; brown (10YR 5/3) silty clay, very dark grayish brown (10YR 3/2) moist; moderate medium subangular blocky structure; very hard, firm, sticky and plastic; few very fine roots; few very fine tubular pores; strongly effervescent with disseminated lime; common, fine, prominent dark yellowish brown (10YR 4/4) moist redoximorphic concentrations; slightly alkaline (pH 7.6); abrupt smooth boundary.
3Ab--35 to 46 inches; grayish brown (2.5Y 5/2) silty clay, very dark grayish brown (2.5Y 3/2) moist; moderate medium subangular blocky structure; very hard, firm, sticky and plastic; few very fine roots; few very fine tubular pores; strongly effervescent with disseminated lime; common, fine, faint dark yellowish brown (10YR 4/6) moist redoximorphic concentrations; slightly alkaline (pH 7.4); clear smooth boundary.
3Bssb1--46 to 60 inches; grayish brown (2.5Y 5/2) silty clay, very dark grayish brown (2.5Y 3/2) moist; moderate medium subangular blocky structure; very hard, very firm, sticky and plastic; few very fine roots; few very fine interstitial and tubular pores; slightly effervescent in fine soft masses; many slickensides and common distinct pressure faces; common fine white sulfate crystals; slightly alkaline (pH 7.4); gradual smooth boundary.
3Bssb2--60 to 74 inches; grayish brown (2.5Y 5/2) silty clay, very dark grayish brown (2.5Y 3/2) moist; moderate medium subangular blocky structure; very hard, very firm, sticky and plastic; few very fine roots; few very fine interstitial and tubular pores; strongly effervescent in fine soft masses; many slickensides and many fine distinct pressure faces; common fine white sulfate crystals; slightly alkaline (pH 7.5).
3C1--74-96 inches; grayish brown (2.5Y 5/2) clay, olive brown (2.5Y 4/4) moist; moderate medium subangular blocky structure; very hard, very firm, sticky and plastic; few very fine roots; few very fine interstitial and tubular pores; strongly effervescent; dark gray (10YR 4/1) redoximorphic depletions; moderately alkaline (pH 8.0).
3C2--96 to 114 inches; light olive brown (2.5Y 5/4) clay; gray (10YR 5/1) redoximorphic depletions; moderately alkaline (pH 8.0).
TYPE LOCATION: Colusa County, California; About 4.5 miles northwest of Grimes, 1260 feet west and 2585 feet north of the southeast corner of section 4, T. 14 N., R. 1 W. MDB&M; 39 Degrees 5 minutes 00 seconds latitude N,and 121 degrees 58 minutes 15 seconds longitude W. Grimes Quadrangle.
RANGE IN CHARACTERISTICS: Mean annual soil temperature ranges from 63 to 65 degrees F. and the temperature remains above 47 degrees F. all year. The 10 to 40 inch textural control section weighted average clay content ranges from 35 to 50 percent. The sodium adsorption ratio ranges from 5 to 13 throughout. The 5 to 16 inch soil moisture control section is dry in all parts from May 15 to October 31 and is moist in all parts from November 15 to May 1.
The Ap horizon has dry color of 10YR 5/2, 5/3; 2.5Y 5/2. Moist color is 10YR 3/2, 3/3; 2.5Y 3/2. Texture is silt loam or loam. Clay content ranges from 20 to 27 percent. Reaction is neutral or slightly alkaline.
The Bw horizons have dry color of 10YR 5/3, 5/2; 2.5Y 5/3, 5/2. Moist color is 10YR 4/2, 3/3, 3/2. Texture is silt loam or silty clay loam and averages 20 to 35 percent clay. Reaction is neutral to slightly alkaline.
The 2Bw horizons have dry colors of 10YR 5/3, 5/2, 4/3; 2.5Y 5/3, 5/2. Moist color is 10YR 4/2, 3/3, 3/2; 2.5Y 4/2. Texture is silty clay and ranges from 40 to 55 percent clay. Reaction is slightly or moderately alkaline.
The 3Ab horizon has dry color of 2.5Y 5/2; 10YR 5/3, 5/2. Moist color is 2.5Y 3/2; 10YR 3/3, 3/2. Texture is silty clay with 40 to 50 percent clay. Reaction is slightly to moderately alkaline.
The 3Bssb horizon has dry color of 10YR 5/3, 5/2; 2.5Y 6/3, 5/3, 5/2. Moist color is 10YR 4/2, 3/2; 2.5Y 4/3, 4/2, 3/2. Texture is silty clay with 40 to 55 percent clay. Reaction is slightly alkaline to moderately alkaline.
The 3C horizon where present has dry color of 2.5Y 5/4, 5/2. Moist color is 2.5Y 4/4. Texture is clay. Reaction is moderately alkaline.
COMPETING SERIES: There are no competing series at this time.
GEOGRAPHIC SETTING: Corbiere soils are on basin rims at elevations of 30 to 70 feet. Slopes are 0 to 2 percent. These soils formed in alluvium derived from mixed rock sources. The climate is subhumid with hot dry summers and cool moist winters with frequent winter fog. Mean annual precipitation is 14 to 16 inches. Mean annual temperature is 60 to 62 degrees F.; mean July temperature is 78 degrees F. and mean January temperature is 45 degrees F. Frost-free season is 225 to 250 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Colusa, Scribner, Hustabel and Willows soils. Scribner soils have fine loamy textural control sections. Colusa soils have a natric horizon. Hustabel soils have coarse loamy textural control sections. Willows soils are fine textured throughout the soil profile.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained. A high water table occurs at 24 to 48 inches from December to April. Runoff is negligible to medium. Permeability is moderately slow from 14 to 22 inches and slow below 22 inches.
USE AND VEGETATION: These soils are used for irrigated cropland. Among the crops commonly grown are tomatoes, corn, rice and winter wheat. Native vegetation in areas not cropped is annual grasses and herbs with scattered oaks.
DISTRIBUTION AND EXTENT: Southwestern part of the Sacramento Valley. These soils are inextensive. MLRA 17.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES PROPOSED: Colusa County, California, Colusa SSA, 1994.
REMARKS: Diagnostic Horizons and features recognized in this
pedon are:
Major Diagnostic Horizons:
1. Mollic Epipedon: 0 to 22 inches, (Ap, Bw1, Bw2)
1.1 Organic matter is greater than 1 percent.
Other Soil Characteristics:
1. PSA and EC from NSSL data:
Horizon Depth(In) SAND SILT CLAY EC
Ap 0-7 20.3 53.8 25.9 1.1
Bw1 7-14 16.8 56.5 26.7 1.2
Bw2 14-22 5.2 63.0 31.8 1.3
2Bw 22-35 2.1 46.5 51.4 1.6
3Ab 35-46 2.2 48.2 49.6 5.4
3Bssb1 46-60 2.5 46.4 51.4 5.2
3Bssb2 60-74 1.5 43.0 54.5 5.5
3C1 74-96 1.5 37.0 61.5 2.9
3C2 96-114 1.2 32.6 66.2 1.8
2. Vertic Subgroup: Linear extensibility to a depth of 100 cm is 6.1 inches.
3. Temperature - Moisture (Xeric-Thermic)
3.1 The 5 to 16 inch SMCS is dry in all parts from May 15 to October 31 and is moist in all parts from November 15 to May 1.
3.2 The soil temperature is above 47 degrees F. for the entire year.
3.3 The MAST is 63 to 65 degrees F.
Edit Notes: 3/99 WRR; Added lower 2 horizons (3C1, 3C2) from NSSL sampled profile.
ADDITIONAL DATA: NSSL pedon # S89CA-011-003 (89P-64).