LOCATION PESCADERO CA

Established Series
Rev. WFA/MAM/WBS/CEJ/AEC
03/2018

PESCADERO SERIES

The Pescadero series consists of very deep, poorly drained soils that formed in alluvium from sedimentary rocks. Pescadero soils are in basins. Slopes are 0 to 2 percent. The mean annual precipitation is about 16 inches and the mean annual temperature is about 60 degrees F.

TAXONOMIC CLASS: Fine, smectitic, thermic Aquic Natrixeralfs

TYPICAL PEDON: Pescadero silty clay loam - on an east facing slope of less than l percent in pasture at 33 feet elevation. (Colors are for dry soil unless otherwise noted.)

An--0 to 3 inches (0 to 8 cm); light gray (2.5Y 7/2) silty clay loam, dark grayish brown (2.5Y 4/2) moist; weak medium platy structure; very hard, friable, sticky and plastic; common very fine roots; common very fine tubular pores; slightly alkaline (pH 7.7) in the upper 1 inch, moderately alkaline (pH 8.0) about an inch to 3 inches below the surface; abrupt wavy boundary. (1 to 5 inches thick)

Btng--3 to 13 inches (8 to 33 cm); gray (5Y 5/1) silty clay, very dark gray (5Y 3/1) moist; strong very coarse prismatic structure; very hard, friable, sticky and plastic; common fine and many medium roots; many very fine tubular pores; many clay films on ped faces and pores; strongly alkaline (pH 8.9); gradual wavy boundary. (6 to 12 inches thick)

Btkng1--13 to 26 inches (33 to 66 cm); light olive gray (5Y 6/2) silty clay, olive (5Y 4/3) moist; common fine prominent strong brown (7.5YR 5/6) masses of oxidized iron and gray (N 5/) masses of reduced iron, brown (7.5YR 4/4) and very dark gray (N 3/) moist; moderate medium prismatic structure that parts to moderate medium and coarse angular blocky structure; very hard, firm, sticky and plastic; common fine and many medium roots; common very fine tubular pores; many moderately thick clay films on faces of peds and lining pores; slightly effervescent with segregated lime as soft masses; strongly alkaline (pH 8.6); clear wavy boundary. (5 to 15 inches thick)

Btkng2--26 to 40 inches (66 to 102 cm); light olive gray (5Y 6/2) silty clay, very dark grayish brown (2.5Y 3/2) moist; many fine prominent strong brown (7.5YR 5/6) masses of oxidized iron, yellowish red (5YR 4/6) moist; moderate medium prismatic structure that parts to moderate medium and coarse angular blocky; very hard, firm, sticky and plastic; few fine and common medium roots; many very fine tubular pores; many moderately thick clay films in pores and continuous moderately thick clay films on faces of peds; slightly effervescent with segregated lime as seams and soft masses; moderately alkaline (pH 8.1); gradual wavy boundary. (7 to 15 inches thick)

Btkng3--40 to 52 inches (102 to 132 cm); light olive gray (5Y 6/2) silty clay loam, olive gray (5Y 4/2) moist; many fine distinct strong brown (7.5YR 5/6) masses of oxidized iron, yellowish red (5YR 4/6) moist; moderate medium prismatic structure that parts to moderate medium and coarse angular blocky structure; hard, firm, sticky and plastic; few very fine and fine roots; many very fine tubular pores; continuous thin clay films on faces of peds, and many moderately thick clay films in pores; strongly effervescent with disseminated and segregated lime as seams; moderately alkaline (pH 7.9); gradual wavy boundary. (9 to 15 inches thick)

Btk--52 to 67 inches (132 to 170 cm); pale brown (10YR 6/3) silty clay loam, brown (10YR 4/3) moist; many fine distinct strong brown (7.5YR 5/8) masses of oxidized iron, brown (7.5YR 4/4) moist; strong medium prismatic structure that parts to strong medium and coarse angular blocky structure; hard, friable, sticky and plastic; few fine roots; many very fine tubular pores; continuous thin clay films on faces of peds, common thin clay films in pores; violently effervescent with lime segregated as seams; moderately alkaline (pH 8.0); gradual wavy boundary. (8 to 15 inches thick)

Bt1--67 to 95 inches (170 to 241 cm); pale brown (10YR 6/3) clay loam, brown (10YR 4/3) moist; many fine distinct strong brown (7.5YR 5/8) masses of oxidized iron, brown (7.5YR 4/4) moist; moderate medium prismatic structure that parts to strong coarse angular blocky structure; slightly hard, friable, moderately sticky, moderately plastic; many very fine tubular pores; clay films on ped faces; violently effervescent; moderately alkaline (pH 8.1); clear wavy boundary.

Bt2--95 to 105 inches (241 to 267 cm); very pale brown (10YR 7/4) silt loam, yellowish brown (10YR 5/6) moist; massive; slightly hard, friable, slightly sticky, slightly plastic; very few fine roots; common very fine tubular and few vesicular pores; common clay films in root channels and pores; moderately alkaline (pH 8.3).

TYPE LOCATION: Yolo County, California; 2 miles southeast of Woodland; 0.3 miles south of Road 24 and 0.25 miles east of the NW corner of sec. 2, T. 9 N., R. 2 E. Greys Bend Quadrangle. 38 degrees 39 minutes 28.3 seconds north latitude, 121 degrees 43 minutes 27.6 seconds west longitude, NAD83.

RANGE IN CHARACTERISTICS: Pescadero soils have redoximorphic features less than 20 inches below the surface. Mean annual soil temperature ranges from about 59 degrees to 62 degrees F. The solum ranges from about 36 to 76 inches in thickness.

The An horizon has dry colors of 10YR 7/2, 6/2, 5/2; 2.5Y 7/2, 6/2 or 5/2. Moist colors are 10YR 5/2, 4/2; 2.5Y 4/2 or 3/2. It is loam, clay loam, silty clay loam or clay. It is medium acid to strongly alkaline inclusive. The Ca/Mg ratio is 0.3/1.0 to 1.0/1.0. Where the soil has an Ap horizon, it lacks natural soil structure but clods or fragments of the horizon have light gray coatings.

The Btng horizon has dry colors of 10YR 5/2, 5/1, 4/2, 4/1; 2.5Y 5/2, 4/2; N5/, N4/; 5Y 5/1 or 4/1. Moist colors are 10YR 4/2, 3/2; 2.5Y 4/2, 3/2; or 5Y 3/1. It is clay or silty clay and has moderate or strong prismatic structure. The exchangeable sodium content is 15 to 70 percent.

The Btkng horizon has dry colors of 10YR 6/3, 6/2; 2.5Y 7/2, 6/2; N6/, N5/; 5Y 6/3, 6/2, 6/1, 5/2 or 5/1. Moist colors are 7.5YR 4/4; 5Y 4/3, 4/2, 4/1 or 3/2. It contains distinct or prominent redoximorphic features and the upper part of the horizon is also mottled in some pedons. It is clay or silty clay. The lower part of the B horizon commonly has angular blocky structure but in some pedons it has prismatic structure. The horizon ranges from moderately alkaline through strongly alkaline and alkalinity tends to increase as depth increases. The horizon contains segregated lime mostly in the lower part. The exchangeable sodium is 15 to 55 percent in the upper part and 5 to 15 in the lower part.

When present, the Bt horizon has dry colors of 10YR 7/4, 7/3, 7/2, 6/4, 6/3, 6/2; 2.5Y 7/4, 7/2, 6/4, 6/2, 5/2; 5Y 6/2 or 6/1. Moist colors are 10YR 5/6, 4/3; 2.5Y 4/2; or 5Y 4/2. Distinct or prominent redoximorphic features are in the upper part of some horizons. The horizon ranges from silt loam through silty clay and is moderately to strongly alkaline.

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

GEOGRAPHIC SETTING: Pescadero soils are in level basins at elevations of 5 to 100 feet. They formed in alluvium from sedimentary rocks. They are in areas that have a dry subhumid mesothermal climate. Summer is hot and dry and winter is cool and moist. Mean annual precipitation is 10 to 19 inches. Mean annual temperature about 60 to 61 degrees F., average January temperature about 45 degrees F., and average July temperature about 77 degrees F. Frost-free period is from 250 to 320 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Capay, Marvin, and Sacramento soils. Capay and Marvin soils lack natric horizons. Sacramento soils have thick mollic epipedons.

DRAINAGE AND PERMEABILITY: Poorly drained or ponded in concave slopes; very slow runoff; very slow permeability.

USE AND VEGETATION: These soils are used mainly for livestock grazing. Some reclaimed areas are used for irrigated field, row crops and irrigated pasture. Commonly cultivated crops are sugarbeets, barley, alfalfa, corn and tomatoes. The vegetation is mainly saltgrass, pickleweed, annual grasses and forbs.

DISTRIBUTION AND EXTENT: Along the west side of the Sacramento and San Joaquin Valleys. The soil is moderately extensive.

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

SERIES ESTABLISHED: Tracy Area, California, 1938.

REMARKS: Diagnostic horizons and features recognized in this pedon are:

Ochric epipedon - the zone from 0 to 3 inches (0 to 8 cm)(An)

Natric horizon - the zone from 3 to 26 inches (8 to 66 cm) (Btng, Btkng1)

Edits made after SDJR projects, incorporated lab pedon description from S1964CA113012 - AEC

National Cooperative Soil Survey
U.S.A.