LOCATION WATSONVILLE CA

Established Series
Rev. RHB/JPR/RWK
06/2015

WATSONVILLE SERIES

The Watsonville series consists of deep, somewhat poorly drained soils that formed in alluvium. Watsonville soils are on old coastal terraces and valleys and have slopes of 0 to 50 percent. The mean annual precipitation is about 28 inches and the mean annual air temperature is about 58 degrees F.

TAXONOMIC CLASS: Fine, smectitic, thermic Xeric Argialbolls

TYPICAL PEDON: Watsonville loam, cultivated. (Colors are for dry soil unless otherwise noted.)

Ap--0 to 12 inches; very dark grayish brown (10YR 3/2) loam, very dark brown (10YR 2/2) moist; moderate medium subangular blocky structure; hard, firm, slight;y sticky and slightly plastic; few fine roots; many very fine tubular pores; slightly acid (pH 6.5); abrupt wavy boundary. (10 to 16 inches thick)

E--12 to 18 inches; light gray (10YR 7/2) sandy loam, dark grayish brown (10YR 4/2) moist; many fine prominent yellowish brown (10YR 5/6) mottles; many fine distinct light brownish gray (10YR 6/2) mottles, moist; moderate medium subangular blocky structure; hard, firm, slightly sticky and slightly plastic; common fine and very fine roots; common fine and very fine tubular pores; slightly acid (pH 6.5); abrupt wavy boundary. (3/8 inch to 24 inches thick)

Bt1--18 to 26 inches; pale brown (10YR 6/3) clay, dark grayish brown (10YR 4/2) moist; common medium prominent brownish yellow (10YR 6/6) mottles; moderate coarse columnar structure; very hard, very firm, very sticky and very plastic; common fine and very fine roots; common fine and very fine tubular pores; continuous thick very dark brown (10YR 2/2) moist clay films on faces of peds; slightly acid (pH 6.4); diffuse wavy boundary. (6 to 11 inches thick)

Bt2--26 to 33 inches; light gray (10YR 7/2) and very pale brown (10YR 7/3) clay, grayish brown (10YR 5/2) moist; common medium prominent brownish yellow (10YR 6/6) mottles; moderate coarse prismatic structure; very hard, very firm, very sticky and very plastic; common fine and fine roots; common fine and very fine tubular pores; continuous thick very dark brown (10YR 2/2) moist clay films on faces of peds; slightly acid (pH 6.3); gradual wavy boundary. (0 to 10 inches thick)

Bt3--33 to 39 inches; light gray (10YR 7/2) and very pale brown (10YR 7/3) clay, grayish brown (2.5Y 5/2) moist; common medium faint light brownish gray (10YR 6/2) mottles; massive; very hard, very firm, very sticky and very plastic; common fine and very fine roots; common fine and very fine tubular pores; continuous thick very dark brown (10YR 2/2) moist clay films on faces of peds; slightly acid (pH 6.3); gradual wavy boundary. (0 to 10 inches thick)

C1--39 to 45 inches; light gray (10YR 7/2) and very pale brown (10YR 7/3) sandy clay loam, grayish brown (2.5Y 5/2) moist; massive; hard, friable, very sticky and plastic; few fine and very fine roots; common fine and very fine tubular pores; many thick colloidal films lining pores; reddish yellow and brownish yellow (7.5YR 7/6; 10YR 6/6) weathered pebbles; slightly acid (pH 6.2); gradual wavy boundary. (0 to 12 inches thick)

C2--45 to 57 inches; variegated light gray (10YR 7/2) very pale brown (10YR 7/3) and yellow (10YR 7/6) sandy clay loam, grayish brown (2.5Y 5/2), brownish yellow (10YR 6/8) and yellowish brown (10YR 5/4) moist; massive; hard, friable, sticky and plastic; few fine and very fine roots; many very fine and fine tubular pores; many thick colloidal films lining pores; moderately acid (pH 6.0). gradual wavy boundary (5 to 15 inches thick)

C3--57 to 63 inches; variegated light gray (10YR 7/2) very pale brown (10YR 7/3) and yellow (10YR 7/6) sandy clay loam, grayish brown (2.5Y 5/2), brownish yellow (10YR 6/8) and yellowish brown (10YR 5/4) moist; massive; hard, friable, sticky, plastic; few fine roots; many fine and very fine tubular pores; common thick colloidal films lining pores; source of thin white (10YR 8/1) particles in horizon undetermined; moderately acid (pH 6.0).

TYPE LOCATION: Santa Cruz County, California; about 950 feet southwest from intersection of East Lake Avenue (Highway 152) and Carlton Road in the SE1/4 NE1/4 NE1/4 section 27, T.11 S., R.2 E. (projected)

RANGE IN CHARACTERISTICS: Solum thickness is 16 to 70 inches.
The soil between depths of 6 and 20 inches is usually dry in all parts for at least 45 consecutive days between the beginning of
July and mid-October and usually moist in all parts for more than
45 consecutive days between the end of of December and the end of April. The mean annual soil temperature is about 59 to 61 degrees
F. Organic matter content is more than 1 percent at depth of 10 inches and less than 1 percent at depth of 20 inches. Base saturation is more than 75 percent in all parts of the profile. Pebbles range from 0 to 7 percent by volume.

The Ap or A horizon is very dark grayish brown, dark gray, dark grayish brown, brown or grayish brown (10YR 3/2, 4/1, 4/2, 4/3,
5/3, 5/2). It is sandy loam, loam, sandy clay loam, or clay loam. This horizon ranges from medium acid to neutral.

The E horizon is light gray, light brownish gray, very pale
brown, or white (10YR 6/1, 6/2, 7/1, 7/2, 8/1, 8/2, 8/3). Some
pedons have yellowish brown, light yellowish brown, strong brown,
or light brown (10YR 5/4, 5/6, 6/4; 7.5YR 5/6, 6/4) mottles with black (10YR 2/1) flakes and granules. Texture is sandy loam,
loam, sandy clay loam or clay loam. Reaction is medium acid to neutral.

The Bt horizon is brown, gray, light brownish gray, pale brown,
light gray, or very pale brown (10YR 5/3, 6/1, 6/2, 6/3, 7/1, 7/2, 7/3; 2.5Y 6/2, 7/2). Most horizons have mottles that are
variegated in colors of yellowish brown, brownish yellow, yellow, brown, light brown, pink, yellowish red or reddish yellow (10YR
5/4, 6/6, 7/6,; 7.5YR 5/4, 6/4, 7/4, 8/4,; 5YR 4/6, 5/6, 6/6). Texture is heavy clay loam or clay. Reaction ranges from medium
acid to moderately alkaline. Some pedons have a BC horizon
that is similar in color to the Bt horizon except lacks mottles
in hue of 5YR. It is sandy clay loam or clay loam. This horizon ranges from medium acid to moderately alkaline.

The C horizon is light gray, pale brown, very pale brown, yellow, light brown, or reddish yellow (2.5Y 7/2; 10YR 6/3, 7/2, 7/3, 7/4, 7/6, 8/3, 8/4; 7.5YR 6/4, 7/6). It is typically sandy clay loam or clay loam, but in a few pedons are strata of sandy loam. This horizon ranges from medium acid to neutral.

COMPETING SERIES: These are the Concepcion and San Simeon series
in the same family and the Milpitas, Postas, Santa Ynez and Tierra series in other families. Concepcion soils have a B2t horizon lacking mottles and ranging in color to redder hues (5YR and 2.5YR). Milpitas, Positas, and Tierra soils lack a mollic epipedon. San Simeon soils have paralithic contact to sandstone at 20 to 40 inches. Santa Ynez soils have a base saturation between 50 to 75 percent in some or all parts of the A horizon.

GEOGRAPHIC SETTING: Watsonville soils are on old marine terraces
and coastal benches and have slopes of 0 to 50 percent. They
formed in sedimentary alluvium at elevations of about 20 to 1,200 feet. The climate is subhumid mesothermal having warm, dry but
foggy summers and cool, moist winters. The mean annual
precipitation is 20 to 35 inches. The average January temperature
is 48 degrees F.; the average July temperature is 68 degrees F.;
and the mean annual temperature is 58 to 60 degrees F. The frost free season is about 250 to 275 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Santa
Ynez soils and the Baywood, Danville, Diablo, Elkhorn, and Pinto soils. Baywood soils have a sandy textural control section. Danville soils lack an albic horizon and have a mollic epipedon thicker than 20 inches. Diablo soils lack an albic horizon and
have more than 30 percent clay in the upper 20 inches if the
surface 7 inches are mixed. Elkhorn and Pinto soils have a fine, loamy textural control section.

DRAINAGE AND PERMEABILITY: Somewhat poorly drained because
perched water tables occur during periods of heavy water applications; slow to rapid runoff; very slow permeability.

USE AND VEGETATION: Used mainly for field and row crops,
irrigated and annual pasture specialty crops such as strawberries
and brussel sprouts, and urban development. Vegetation is mainly annual grasses, forbs, and a few coastal chaparral plants.

DISTRIBUTION AND EXTENT: Coastal terraces and valleys along the central California coast. The soils are inextensive.

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

SERIES ESTABLISHED: Pajaro Valley Area, Santa Cruz County, California, 1908.

REMARKS: Diagnostic horizons and features recognized in this pedon are: Mollic epipedon - 0 to 12 inches (Ap horizon)

Albic horizon - 12 to 18 inches (E horizon)

Argillic Horizon - 18 to 39 inches (Bt1, Bt2 and Bt3 horizons)

Particle-size control section - 18 to 38 inches (upper 20 of the argillic horizon

Xeric moisture regime

National Cooperative Soil Survey
U.S.A.