LOCATION CHATEAU CAEstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, thermic Aquic Haploxerepts
TYPICAL PEDON: Chateau clay - on a slope of 1 percent in a fallow cultivated field at 135 feet elevation. (Colors are for dry soil unless otherwise stated. When described on May 31, 1977, the soil was dry to 15 inches, moist to 60 inches, saturated below 60 inches.)
Ap1--0 to 6 inches; brown (10YR 5/3) clay, very dark grayish brown (10YR 3/2) moist; weak medium and coarse subangular blocky structure; very hard, friable, slightly sticky and moderately plastic; few very fine roots; common very fine tubular and interstitial pores; electrical conductivity is 14 decisiemens per meter; sodium adsorption ratio is 26; few fine distinct yellowish brown (10YR 5/6) moist redoximorphic masses of iron accumulation; strongly alkaline (pH 8.5); clear smooth boundary. (3 to 12 inches thick)
Ap2--6 to 15 inches; brown (10YR 5/3) clay, very dark grayish brown (10YR 3/2) moist; strong medium angular blocky structure; hard, very firm, slightly sticky and very plastic; few very fine roots; few very fine tubular pores; common thin clay films on faces of peds; electrical conductivity is 12 decisiemens per meter; sodium adsorption ratio is 27; few fine distinct yellowish brown (10YR 5/4) moist redoximorphic masses; strongly alkaline (pH 8.5); abrupt wavy boundary. (3 to 16 inches thick)
Bt1--15 to 23 inches; yellowish brown (10YR 5/4) clay; dark yellowish brown (10YR 4/4) moist; strong medium angular blocky structure; hard, firm, moderately sticky and very plastic; few very fine tubular pores; many thin clay films on faces of peds; electrical conductivity is 11 decisiemens per meter; sodium adsorption ratio is 25; few fine gypsum crystals; many medium faint dark yellowish brown (10YR 3/4) moist redoximorphic masses; strongly alkaline (pH 8.5); gradual smooth boundary. (4 to 30 inches thick)
Bt2--23 to 44 inches; yellowish brown (10YR 5/4) silty clay, dark yellowish brown (10YR 4/4) moist; weak medium subangular blocky structure; hard, friable, very sticky and very plastic; few very fine tubular pores; common thin clay films on faces of peds and line pores; sodium adsorption ratio is 21; common fine prominent very dark grayish brown (2.5Y 3/2) moist redoximorphic masses; strongly alkaline (pH 8.5); gradual smooth boundary. (14 to 30 inches)
C--44 to 62 inches; yellowish brown (10YR 5/4) silty clay, dark yellowish brown (10YR 4/4) moist; massive; slightly hard, friable, moderately sticky and very plastic; common very fine tubular pores; many colloidal stains; slightly effervescent, carbonates disseminated; sodium adsorption ratio is 29; many medium faint dark yellowish brown (10YR 3/4) moist redoximorphic masses; strongly alkaline (pH 8.5).
TYPE LOCATION: Merced County, California; approximately 5.5 miles southwest of the city of Dos Palos and between the Outside and the Main canals; 1,000 feet north and 400 feet west of the southeast corner of section 31, T. 11 S., R. 12 E., MDB&M; Latitude 36 degrees, 55 minutes, 38 seconds north and Longitude 120 degrees, 41 minutes, 30 seconds west; USGS Dos Palos Topographic Quadrangle, NAD 27.
RANGE IN CHARACTERISTICS: These soils are saturated with stagnant water for at least a few days. Thickness of the A horizons is 6 to 23 inches because of land leveling. Organic matter is less than 1 percent in the upper 15 inches and decreases regularly with depth. Redoximorphic masses occur throughout the profile with moist chromas ranging from 2 to 6. Moist chroma of 2 in the matrix does not occur directly under the epipedon within a depth of 20 inches.
The A horizon has color of 10YR 4/3, 5/2, 5/3 or 5/4. Moist color is 10YR 3/2, 3/3, 4/2, 4/3 or 5/3. Clay content is 40 to 60 percent. Electrical conductivity is 4 to 16 decisiemens per meter. Sodium adsorption ratio is 13 to 30. Reaction is slightly alkaline to strongly alkaline.
The Bt and Btg horizons have color of 10YR 5/3, 5/4 or 6/4. Moist color is 10YR 3/2, 3/3, 3/4, 4/3, 4/4; 2.5Y 3/2, 4/4or 5/4. Texture is clay loam, silty clay loam, silty clay or clay. Clay content is 35 to 60 percent. Electrical conductivity is 8 to 16 decisiemens per meter. Sodium adsorption ratio is 13 to 30.Reaction is moderately alkaline or strongly alkaline.
The C horizon has color of 10YR 5/4, 6/3 or 6/4. Moist color is 10YR 3/3, 4/2, 4/3, 4/4, 5/4; 2.5Y 5/4or 4/4. Texture is silty clay or clay. Clay content is 40 to 60 percent. Electrical conductivity is 8 to 16 decisiemens per meter. Sodium adsorption ratio is 13 to 40. The lower part of the C horizon is noncalcareous in a few pedons. Small fragments 1 to 3 cm long and 0.5 to 1 cm thick of strongly decomposed clayey shale and about
2 percent fine (less than 2 mm diameter) gypsum crystals occur in some pedons.
COMPETING SERIES: There are no competing series at this time.
GEOGRAPHIC SETTING: Chateau soils are on fan skirts and low alluvial fans adjacent to the valley basin rim. Slope is 0 to 2 percent. These soils formed in alluvium derived from sedimentary rocks. Most of this soil has been leveled but was gently sloping and hummocky in its natural relief. Elevation is 110 to 185 feet. The climate is semiarid with hot dry summers and cool moist winters. The mean annual precipitation is 8 to 12 inches. The mean January temperature is 46 degrees F.; mean July temperature is 79 degrees F. and the mean annual temperature is 60 to 64 degrees F. Frost-free season is 210 to 280 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dosamigos, Santanela, Triangle, and Turlock soils. Dosamigos soils, on low alluvial fans adjacent to the valley basin rim, have a mollic epipedon. Santanela and Turlock soils, on valley basins, have a natric horizon and a fine-loamy particle-size control section. Triangle soils, on valley basins, have intersecting slickensides and develop wide cracks when dry.
DRAINAGE AND PERMEABILITY: Poorly drained; negligible, low or medium runoff; slow permeability. These soils now have improved drainage and have had some of their water sources intercepted. The water table is now 3.5 to 5 feet from December to March. Some areas are ponded for waterfowl habitat. These areas have ponded conditions with water on the surface and a water table as deep as 3 feet from September to March.
USE AND VEGETATION: Most of this soil is used for irrigated field crops such as alfalfa and pasture with some areas used for livestock grazing.
DISTRIBUTION AND EXTENT: These soils are distributed along the western edge of the San Joaquin Valley. They are not extensive. MLRA 17.
MLRA OFFICE RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Merced County, California 1984.
REMARKS: These soils were formerly mapped as the Lethent series in the Los Banos Area, California 1939 Series Report. They differ by not having an argillic horizon and having a xeric moisture regime.
Very slow runoff terminology adjusted to read negligible, low or medium, to comply with adjective criteria of the Soil Survey Manual dated 10/93.
Diagnostic horizon and features recognized in this pedon are:
1. Ochric Epipedon (0 to 15 inches) - The organic matter is less than 1 percent and the thickness ranges from 7 to 23 inches.
2. Cambic Horizon (15 to 23 inches) - Moist color drops 1 unit in hue, 2 units in value, and 2 units in chroma (sesquioxides-gleying). Clay content increases 2 to 5 percent but does not qualify as an argillic horizon.
3. Aquic Subgroup - Formed under aquic conditions but now is protected. Profile still saturated for a short period of time by water table and stagnant surface water. These soils have an aquic moisture regime, but do not have moist chromas of 2 in the matrix directly under the epipedon within a depth of 20 inches that would qualify them for the Aquept suborder.