LOCATION WESTSHORE CA
Established Series
JFR/DCE/RLR
04/2019
WESTSHORE SERIES
The Westshore series consists of deep, well drained soils that formed in fine alluvium derived from mixed rock sources. Westshore soils are on marine terraces and have slopes of 2 to 9 percent. The mean annual precipitation is about 225 millimeters (9 inches) and the mean annual temperature is about 16.5 degrees C. (62 degrees F.)
TAXONOMIC CLASS: Clayey-skeletal, smectitic, isothermic Typic Natrustalfs
TYPICAL PEDON: Westshore very cobbly silt loam - on a marine terrace of 3 percent slopes under a cover of desert thorn, golden snake cactus, tarweed, ripgut brome, red brome, goldentop and clover. (When described on 5/2/82, the soil was dry to 15 centimeters (6 inches) slightly moist to 48 centimeters (19 inches) and moist below. Colors are for dry soil unless otherwise stated).
E--0 to 15 centimeters (0 to 6 inches); light brownish gray (10YR 6/2) and pale brown (10YR 6/3) very cobbly silt loam, dark grayish brown (10YR 4/2) and dark brown (10YR 3/3) moist; strong thick and very thick platy structure; hard, very friable, slightly sticky and slightly plastic; common very fine and fine and few medium roots; many very fine tubular and interstitial pores; 10 percent stones, 25 percent cobbles and 10 percent gravel; neutral (pH 7.0); abrupt wavy boundary. (5 to 18 centimeters; 2 to 7 inches thick).
Btn1--15 to 48 centimeters (6 to 19 inches); grayish brown (10YR 5/2) very cobbly clay, very dark grayish brown (10YR 3/2) moist; moderate medium and coarse prismatic and strong fine and medium angular blocky structure; extremely hard, friable, very sticky and very plastic; common very fine and fine roots; common very fine tubular pores; common moderately thick clay films, few pressure faces; about 20 percent of peds coated with silans; 15 percent stones, 25 percent cobbles, and 10 percent gravel about 3 percent are rounded; SAR is 28; moderately alkaline (pH 8.0); clear wavy boundary. (25 to 38 centimeters; 10 to 15 inches thick)
Btn2--48 to 66 centimeters (19 to 26 inches); brown (10YR 5/3) very cobbly clay, dark brown (10YR 3/3) moist; strong medium and coarse prismatic structure; extremely hard, friable, very sticky and very plastic; common very fine roots; common very fine tubular pores; common faint clay films on ped faces, common pressure faces; 15 percent stones, 25 percent cobbles, and 10 percent gravel; SAR is 42; slightly acid (pH 6.5); gradual wavy boundary. (13 to 23 centimeters; 5 to 9 inches thick)
Btn3--66 to 107 centimeters (26 to 42 inches; brown (10YR 4/3) very cobbly clay, dark brown (10YR 3/3) moist; strong coarse prismatic structure; extremely hard, friable, very sticky and very plastic; few very fine roots; common very fine tubular pores; common pressure faces; SAR is 46; 15 percent stones, 30 percent cobbles and 10 percent gravel; slightly alkaline (pH 7.5); abrupt wavy boundary. (33 to 50 centimeters; 13 to 20 inches thick)
2Cn--107 to 152 centimeters (42 to 60 inches); light yellowish brown (10YR 6/4) extremely stony sandy loam; few very fine roots; 25 percent stones, 30 percent cobbles and 30 percent gravel; slightly alkaline (pH 7.5).
TYPE LOCATION: Los Angeles County, California, San Clemente Island, about 2.75 miles south of air terminal and then 2.9 miles going west and south on Dirt Westshore Road, the right 450 feet and 100 feet north to site.; 32.9607300 degrees latitude, -118.5621500 degrees longitude; UTM Zone 11, 3648016.59n, 353998.40e; U.S.G.S. Quad Name: San Clemente Island Central, California.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature is about 17.5 degrees C. (about 64 degrees F.). The soil temperature is above 8 degrees C. (47 degrees F.) the entire year, and the difference between the mean summer and mean winter soil temperature is less than 6 degrees C.
Soil moisture control section between depths of 18 and 36 centimeters (7 and 14 inches) is dry in all parts from May until early October and is continuously moist in some or all parts from November to about April.
Thickness of solum: 75 to 115 centimeters (30 to 45 inches)
Rock fragments content: 3 to 15 percent stones, 25 to 30 percent cobbles and 10 to 20 percent gravel.
Reaction: neutral or mildly alkaline.
Exchangeable sodium percentage (ESP): 25 to 45 percent
Sodium absorption ratio (SAR): 25 to 55 meq/L
Electrical conductivity (EC): 4 to 12 ds/m in the upper part of the argillic horizon and 12 to 16 ds/m in the lower part.
Substratum: some pedons are underlain by hard andesite or dacite bedrock.
A or E horizon
Dry color of 10YR 3/2, 3/3, 3/4, 4/2, or 4/3
Texture: very cobbly/stony silt loam or cobbly/stony silt loam
Clay content: 15 to 20 percent
Bt horizon
Dry color: 10YR 4/2, 5/3, 5/4, 7.5YR 5/2, 4/4, or 5/4
Moist color: 10YR 3/2, 3/3, 3/4, 7.5YR 3/2, or 4/4
Texture: very cobbly/stony clay and very cobbly/stony clay
Clay content: 50 to 65 percent in the upper part and 65 to 80 percent in the lower part.
2C horizon
Dry color: 2.5Y 7/4 or 10YR 6/4
Moist color: 2.5Y 5/2 or 10YR 5/3
Texture: typically extremely stony sandy loam
Electrical conductivity: 12 to 16 ds/m
Rock fragment content: 20 to 25 percent stones; 25 to 30 percent cobbles; and 20 to 25 percent gravel. Boulders and rock outcrops are present in some places.
Some pedons are underlain by hard, dacite or andesite bedrock.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Landscape: islands
Landform: marine terraces
Slopes: 2 to 9 percent
Parent material: extremely stony marine sediments and alluvium.
Elevations: nearly sea level to 120 meters (0 to 400 feet)
Climate: maritime with dry mild summers and moist, mild winters. Fog is common during the summer months.
Mean annual precipitation: 205 to 245 millimeters (8 to 9.5 inches)
Mean annual temperature: 16 to 17.5 degrees C. (61 to 64 degrees F.)
Frost-free season: 365 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Eelcove soils: have less than 35 percent rock fragments and are on similar landforms.
Eelpoint soils: are moderately-deep to a lithic contact and are on hills or terraces.
Notspier soils: are moderately-deep to a paralithic contact and are on hills or terraces.
Sanclemente soils: have less than 35 percent rock fragments, are moderately-deep to a lithic contact and are on hills or terraces.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well-drained, slow to medium runoff; low saturated hydraulic conductivity.
USE AND VEGETATION: This soil is used for wildlife habitat and military maneuvers. Vegetation is mostly Cholla, australian saltbush, desert boxthorn, red brome, ripgut brome, goldentop and clover.
DISTRIBUTION AND EXTENT: San Clemente Island coastal terraces, Southern California Mountains, MLRA 20. These soils are not extensive.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: San Clemente Island, Los Angeles County, California, 1982. Series name is for the West Shore Road.
REMARKS:
Diagnostic horizons recognized in this pedon are:
Ochric epipedon: the zone from a depth of 0 to 15 centimeters
Natric horizon: the zone from a depth of 15 to 107 centimeters
OSD revised during correlation of the San Clemente Island Interim Report in 2018.
ADDITIONAL DATA:
NASIS User Site/Pedon ID: 1982CA037WESTSHORE
Classified using the Twelfth Editions Keys to Soil Taxonomy (2014)
National Cooperative Soil Survey
U.S.A.