LOCATION BRITTO CAEstablished Series
TAXONOMIC CLASS: Fine, smectitic, thermic Typic Natraqualfs
TYPICAL PEDON: Britto clay loam, on a hummocky slope of 1 percent under iodine bush, saltgrass, Bermuda grass, spikeweed, soft chess and burclover vegetation at an elevation of 110 feet. (Colors are for dry soil unless otherwise stated. When described on June 1, 1977, the soil was moist throughout).
A--0 to 1 inches; light gray (10YR 6/1) clay loam, grayish brown (10YR 3/2) moist; strong fine platy structure; very hard, friable, sticky and plastic; many very fine roots; mildly alkaline (pH 7.5); abrupt smooth boundary. (1/2 to 3 inches thick)
E--1 to 5 inches; light brownish gray (2.5Y 6/2) clay loam, dark grayish brown (2.5Y 4/2) moist; common fine prominent reddish yellow (7.5YR 6/8) mottles, common fine prominent strong brown (7.5YR 4/6) mottles moist; weak coarse angular blocky structure; very hard, firm, sticky and plastic; common very fine and few fine and medium roots; 30 percent clay content; neutral reaction (pH 7.0); abrupt smooth boundary. (1/2 to 7 inches thick)
Btn1--5 to 16 inches; olive gray (5Y 5/2) clay, dark gray (5Y 4/1) moist; many fine and medium prominent olive brown (2.5Y 4/4) and common fine prominent greenish gray (5GY 5/1) and dark greenish gray (5GY 4/1) mottles moist; strong very coarse, coarse and medium columnar structure; very hard, very firm, very sticky and very plastic; common very fine and few fine roots; few very fine tubular pores; many moderately thick pressure faces; 51 percent clay content; EC is 2.1 mmhos/cm; ESP is 20; strongly alkaline (pH 8.5); clear wavy boundary.
Btn2--16 to 22 inches; light yellowish brown (10YR 6/4) clay; brown (10YR 4/3) moist; moderate coarse angular blocky structure; very hard, friable, very sticky and very plastic; few very fine and fine roots; few very fine tubular pores; many thin clay films line pores; 48 percent clay content; EC is 5.0 mmhos/cm; ESP is 24; slightly effervescent with disseminated lime; strongly alkaline (pH 8.5); clear wavy boundary. (Combined thickness of the Btn is 15 to 24 inches)
Btn3--22 to 37 inches; light yellowish brown (2.5Y 6/4) clay, dark yellowish brown (10YR 4/4) moist; dark yellowish brown (10YR 4/6) root stains on peds; moderate medium angular blocky structure; hard, firm, very sticky and very plastic; few very fine roots; common very fine tubular pores; many moderately thick pressure faces; slightly effervescent with disseminated lime, strongly alkaline (pH 8.5); clear wavy boundary. (10 to 20 inches thick)
Bny--37 to 62 inches; light yellowish brown (10YR 6/4) clay, yellowish brown (10YR 5/6) moist; few fine distinct yellow (10YR 7/8) and gray (5Y 6/1) mottles moist; weak medium subangular blocky structure; hard, friable, very sticky and very plastic; few very fine roots; few very fine tubular pores; EC is 20 mmhos/cm; ESP is 25; strongly effervescent with disseminated lime. 10 percent gypsum masses 2 mm in size; strongly alkaline (pH 8.5).
TYPE LOCATION: Merced County, California; about 6 miles SE of the city of Los Banos, 0.85 mile (4,500) west of the intersection of Santa Cruz and Santa Cruz Gun Club Road, 0.45 mile south of Almond Drive, 200 feet NW of pump house, 2,400 feet south and 150 feet east of the NW corner (in the SW 1/4, SW 1/4, NW 1/4) of sec. 8, T. 11 S., R. 11 E.
RANGE IN CHARACTERISTICS: In many areas the entire profile is saturated from September through May by a water table and stagnant surface water. The water table ranges from a depth 12 to 36 inches October through March. The soil temperature reflects the water temperature when inundated. The soil temperature is warmer than 47 degrees F. from February 15 to December 1.
The A horizon ranges from 27 to 35 percent clay content. The E horizon ranges from 27 to 30 percent clay content. The Btn horizon ranges from 35 to 55 percent clay content and has at least 8 percent clay (absolute) more than the A horizon. The EC of the profile ranges from 2 to 20 mmhos/cm. The ESP of the Btn horizon ranges from 16 to 30.
The A horizon is 10YR 5/2, 5/3, 6/1, 6/2, 6/3; or 5Y 5/1. Moist colors are 10YR 3/1, 3/2, 3/3, 4/2; or 5Y 4/1. Some pedons have few fine prominent 10YR 6/6 mottles when moist. It is mildly alkaline or moderately alkaline.
The E horizon is 10YR 6/3; 2.5Y 6/2, 6/4; or 5Y 8/1. Moist colors are 10YR 4/1, 4/3; or 5Y 6/2. Mottles are common fine prominent 7.5YR 6.8 or 10YR 3/1. Moist mottles are common fine prominent 7.5YR 4/6 or 10YR 5/3. It is neutral or mildly alkaline.
The Btn horizon is 10YR 3/3, 4/4, 5/2, 6/4; 2.5Y 4/2, 5/4; or 5Y 5/2. Moist colors are 10YR 4/2, 4/3; 2.5Y 4/1, 4/2, or 5/3. Mottles are many fine or medium distinct 2.5Y 4/4; or 5Y 4/4 or common fine prominent 10YR 3/1; N 2/0 or common fine or medium prominent 5Y 4/2; 5GY 4/1, or 5/1. It is clay loam or clay. It is non to strongly effervescent and is moderately alkaline or strongly alkaline.
The Bny horizon is 10YR 5/2, 5/3, 6/6; 2.5Y 4/4, 5/2 or 6/4. Moist colors are 10YR 4/3, 4/4, 5/4, 5/6; 5Y 3/1, 4/3 or 5/3. Moist mottles are few fine prominent N 2/0, few fine distinct 10YR 7/8, or common fine prominent 7.5YR 4/4; 10YR 2/2 or 5Y 6/1. It is sandy clay loam, clay loam or clay, with 30 to 50 percent clay content. It is slightly or strongly effervescent and has few fine to common medium soft lime masses. Some pedons do not have gypsum masses. It is moderately alkaline or strongly alkaline.
COMPETING SERIES: These are the Edminster, Kesterson, Santanela, Turlock and Volta series in other families. Edminster, Kesterson, Santanela, and Turlock soils are fine-loamy. In addition Edminster and Kesterson soils are not inundated for very long periods of time. Volta soils have a duripan at depths of 45 to 55 inches.
GEOGRAPHIC SETTING: Britto soils are in the valley basin rim. They have developed in mixed alluvium derived dominantly from sedimentary sources. Slopes are 0 to 2 percent. Elevations are 80 to 125 feet. The climate is semiarid with hot dry summers and cool moist winters. Mean annual precipitation is about 9 to 12 inches. Mean January temperature is 46 degrees F.; mean July temperature is 79 degrees F.; and mean annual temperature is about 62 degrees F. The frost free season is 210 to 280 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Edminster and Turlock soils and Agnal, Chateau, Dosamigos, Dospalos, Marcuse, and Triangle soils. Agnal soils do not have an argillic horizon and have a thick mollic epipedon and a salic horizon. Chateau, Dosamigos, Dospalos, and Marcuse soils do not have natric horizons and are somewhat poorly or poorly drained. Triangle soils have wide cracks when dry and lack a natric horizon.
DRAINAGE AND PERMEABILITY: Very poorly drained; ponded from September through May except where drained and leveled; very slow permeability.
USE AND VEGETATION: These soils are ponded (inundated) and used for waterfowl hunting with use as rangeland for limited grazing during the spring and between hunting seasons. The drained and leveled areas are used for cropland to produce barley and as pastureland for livestock grazing. The vegetation is iodinebush, saltgrass, Bermudagrass, spikeweed, soft chess, burclover, and wild barley.
DISTRIBUTION AND EXTENT: These soils are in the basin rim of the central part of the San Joaquin Valley in California. They are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Merced County, California 1984.
REMARKS: These soils were formerly included with and mapped as the Orestimba series in the Los Banos Area, series 1939 report. pH determined by colorimetric method using Thymol Blue and Hellige-Troug Triplex indicators. Textures determined by modified Bouyoucos method. Presence of lime determined by 10 percent HC1. EC determined from saturation extract. ESP determined by versenate method.