LOCATION CHUALAR CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, thermic Typic Argixerolls
TYPICAL PEDON: Chualar sandy loam - irrigated row crops. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 7 inches; dark grayish brown (10YR 4/2) sandy loam, very dark grayish brown (10YR 3/2) moist; weak medium granular and weak medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common very fine roots; many very fine interstitial pores; slightly alkaline (pH 7.6); clear smooth boundary. (5 to 10 inches thick)
A--7 to 21 inches; dark grayish brown (10YR 4/2) heavy sandy loam, very dark grayish brown (10YR 3/2) moist; moderate medium and coarse granular structure; hard, friable, slightly sticky and slightly plastic; few very fine roots; many very fine interstitial pores; slightly alkaline (pH 7.6); clear wavy boundary. (10 to 14 inches thick)
BAt--21 to 30 inches; yellowish brown (10YR 5/4) light sandy clay loam, dark brown (10YR 3/3) moist; massive; hard, friable, sticky and plastic; few very fine roots; many very fine interstitial, common very fine and few fine tubular pores; common thin clay films as bridges between minerals grains and lining pores; many crotovinas; slightly alkaline (pH 7.8); clear smooth boundary. (8 to 12 inches thick)
Bt1--30 to 44 inches; brown (7.5YR 5/4) sandy clay loam, dark brown (7.5YR 3/2) moist; crushed color brown (7.5YR 4/4); weak coarse angular blocky structure; very hard, firm very sticky and plastic; common very fine interstitial pores; continuous thin clay films lining pores, continuous thin clay films on faces of peds; slightly alkaline (pH 7.6); diffuse smooth boundary. (8 to 15 inches thick)
Bt2--44 to 55 inches; brown (7.5YR 5/4) gravelly heavy sandy loam, dark brown (7.5YR 3/2) moist; rubbed color brown (7.5YR 4/4); massive; very hard, firm, very sticky and plastic; common very fine interstitial and few very fine tubular pores; continuous thin clay films lining pores and a few moderately thick clay films lining pores; 15 percent fine gravel; neutral (pH 7.3); clear smooth boundary. (10 to 21 inches thick)
BC--55 to 59 inches; brown (7.5YR 5/4) gravelly coarse sandy loam, dark brown (7.5YR 4/4) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; many very fine interstitial pores; few thin clay films as bridges between mineral grains; 20 percent gavel; neutral (pH 7.3); abrupt smooth boundary. (4 to 10 inches thick)
2C--59 to 80 inches; brown (7.5YR 5/4) fine gravelly coarse sand, dark brown (7.5YR 4/4) moist; single grained; loose; many fine interstitial pores; 20 percent gravel; neutral (pH 7.2). (Many feet thick)
TYPE LOCATION: Monterey County, California; about one mile northeast from Chualar; 0.45 miles southwest on Chualar Road from Old State Road to pump house on north side of road, 830 feet northwest on unpaved road, 20 feet northeast into field.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 59 to 63 degrees F., and the soil temperature usually is not below 47 degrees F. at any time. The difference between mean summer and mean winter temperatures is less than 19 degrees F. The soil from about 6 to 20 inches usually is dry all of the time from late April or May until November or early December and is moist in some or all parts the rest of the year. Coarse and very coarse angular sand particles make up 20 to 30 percent of the A and C horizons and 20 to 25 percent of the Bt horizon. Rock fragments, mostly fine angular gravel, range from 1 to 2 percent to about 25 percent, but most pedons have less than 15 percent gravel. Also there are numerous mica particles throughout the profile. Base saturation is more than 75 percent throughout.
The A horizon is 10YR 5/3, 5/2, 4/3, 4/2, 3/3; 7.5YR 5/4, 5/2, 4/4, 4/2 or 3/2. Moist colors have values or chromas of 3 or less. It is sandy loam or loam and it is slightly acid or neutral. In some pedons, the A horizon is slightly alkaline because of soil amendments, irrigation water or other cultural measures. It has weak or moderate granular or subangular blocky structure and is slightly hard or hard. Organic matter content is 1 to 4 percent to a depth of more than 10 inches and decrease regularly and is less than 1 percent at a depth of 20 inches. The lower boundary is diffuse or there is a transitional AB or BA horizon. Note: reaction of the A horizon and possibly of the BA horizon is alkaline because of fertilizers or amendments.
The Bt horizon is 7.5YR 6/6, 6/4, 5/2, 5/4; 10YR 4/2, 5/3, 5/4. It is heavy sandy loam or sandy clay loam and average 18 to 25 percent clay. This horizon is massive or has weak to moderate angular blocky structure. It is slightly acid to slightly alkaline in the upper part and is moderately alkaline in the lower part of some pedons.
The C horizon is 10YR 5/2, 5/3, 5/4, 6/2, 6/3, 6/4; 7.5YR 5/2, 5/4, 5/6, 6/6. It is somewhat stratified loamy sand, sandy loam, or light sandy clay loam. It is neutral to moderately alkaline. Some pedons are calcareous.
COMPETING SERIES: These are the Ballard, Bohna, Chuloak (T), Franciscan, Gilroy, Pinto, Sagaser, Shimmon, Soper and Tehachapi series. Ballard soils have less than 20 percent coarse and very coarse sand particles and have weakly developed (minimal) Bt horizons. Bohna and Sagaser soils have a paralithic contact at depth of 40 to 60 inches. Chuloak soils have temperatures in which the difference between mean summer and mean winter is greater then 30 degrees F. Franciscan soils are moderately deep to a lithic contact. Gilroy, Shimmon and Soper soils have bedrock at depths of 20 to 40 inches. Pinto soils have an abrupt A/B horizon boundary and lack a transitional AB or BA horizon. Tehachapi soils have a Bt horizon with 25 to 35 percent clay and a slow permeability.
GEOGRAPHIC SETTING: The Chualar soils are on alluvial fans and stream terraces at elevations of 50 to 2,000 feet. Slopes are 0 to 9 percent. The climate is dry with 12 to 25 inches of precipitation. The average January temperature is 45 to 49 degrees F.; average July temperature is 62 to 67 degrees F.; and the mean annual temperature is 57 to 62 degrees F. The frost-free season is 175 to 300 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Arroyo Seco, Danville, Elder, Gloria, Hanford, and Placentia soils. Arroyo Seco, Elder and Hanford soils lack argillic horizons. Danville soils have a mollic epipedon more than 20 inches thick and have more than 35 percent clay in the Bt horizon. Gloria soils have a duripan. Placentia soils have a Bt horizon with Exchangeable Sodium Percentage of 15 or more and more than 35 percent clay.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderately slow permeability.
USE AND VEGETATION: Used mainly for growing irrigated row crops, field crops, orchards, vineyards, and dry farmed grain. Vegetation is annual grasses and forbs and in some places, a few scattered oaks.
DISTRIBUTION AND EXTENT: Chualar soils occur in the intermountain valleys of the Coast Range of California. They are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Monterey County (Salinas Area), California, 1925.
REMARKS: The soils mapped in Sacramento and San Joaquin Valleys are now the new tentative Chuloak series. These soils have temperatures difference between mean summer and mean winter of 30 degrees F. or more. The soils mapped near King City are considered taxadjuncts to the series because of slight temperatures differences.
The activity class was added to the classification in February of 2003. Competing series were not checked at that time. - ET
Last revised by the state on 4/86.
ADDITIONAL DATA: Riverside Laboratory, Pedon No. S64-Calif-27-13