LOCATION SANCLEMENTE CA
Established Series
DCE/RLR
04/2019
SANCLEMENTE SERIES
The Sanclemente series consists of moderately deep well drained soils that formed in fine alluvium derived from mixed rock sources resting over volcanic rock. Sanclemente soils are on hills and terraces and have slopes of 2 to 30 percent. The mean annual precipitation is about 245 millimeters (9.5 inches) and the mean annual temperature is about 17 degrees C. (62.5 degrees F.).
TAXONOMIC CLASS: Very-fine, smectitic, isothermic Sodic Haplusterts
TYPICAL PEDON: Sanclemente cobbly silt loam - on a 9 percent slope facing northwest under a cover of slender oats, mouse barley, ripgut brome, desert thorn and Australian saltbush at 110 meters (360 feet) elevation. (colors are for dry soil unless otherwise stated. When described on 4/27/82 the soil was dry on the surface and slightly moist below.)
E--0 to 5 centimeters (0 to 2 inches); brown (10YR 5/3) and pale brown (10YR 6/3) cobbly silt loam, dark brown (10YR 3/3) moist, strong medium to very thick and weak thin and medium platy structure; hard, very friable; slightly sticky and slightly plastic; common very fine and few medium roots; common very fine tubular and few very fine interstitial pores; 15 percent cobbles and 5 percent gravel; moderately alkaline (pH 8.0); abrupt smooth boundary. (0 to 8 centimeters; 0 to 3 inches thick).
A1--5 to 20 centimeters (2 to 8 inches); grayish brown (10YR 5/2) clay, very dark grayish brown (10YR 3/2) moist; strong medium and coarse prismatic parting to coarse and very coarse angular blocky structure; extremely hard, friable, very sticky and very plastic; common very fine and fine roots mostly on faces of peds; few very fine tubular pores; 3 percent rounded gravel; moderately alkaline (pH 8.0); gradual wavy boundary.
A2--20 to 46 centimeters (8 to 18 inches); grayish brown (10YR 5/2) clay, dark grayish brown (10YR 4/2) moist; strong very coarse prismatic structure; extremely hard, friable, very sticky and very plastic; few very fine and fine roots mostly on faces of peds; few very fine tubular pores; 3 percent gravel; few wedge shaped aggregates tilting 30 to 60 degrees from their horizontal and very few slickensides that intersect; slightly acid (pH 6.5); gradual wavy boundary. (25 to 50 centimeters; 10 to 25 inches thick).
Bss1--46 to 79 centimeters (18 to 31 inches); grayish brown (10YR 5/2) clay, dark grayish brown (10YR 4/2) moist; strong very coarse prismatic structure; extremely hard, friable, very sticky and very plastic; few very fine and fine roots mostly on faces of peds; few very fine tubular pores; 3 percent gravel; few wedge shaped aggregates tilting 30 to 60 degrees from their horizontal and very few slickensides that intersect; SAR is 32; slightly acid (pH 6.5); gradual wavy boundary.
Bnss2--79 to 91 centimeters (31 to 36 inches); grayish brown (10YR 5/2) clay, dark grayish brown (10YR 4/2) moist; strong very coarse prismatic structure; extremely hard, friable, very sticky and very plastic; few very fine and fine roots; few very fine tubular pores; 5 percent gravel; few weak intersecting slickensides and few wedge shape aggregates; SAR is 34; slightly acid (pH 6.5); abrupt irregular boundary. (40 to 85 centimeters; 15 to 34 inches thick)
2R--91 centimeters (36 inches); hard andesite, with fractures 15 to 36 centimeters (6 to 14 inches) apart.
TYPE LOCATION: San Clemente Island, Los Angeles County, California; about .75 mile going south from air terminal, then left about 1,800 feet northwest from paved road and about 300 feet east to site.; 33.01855 degrees latitude, -118.5726900 degrees longitude; UTM Zone 11; 3654442.16n, 353109.05e; U.S.G.S. Quad Name: San Clemente Island, North, California.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature: 17.5 degrees C. (about 64 degrees F.) The difference between the mean summer and mean winter temperature is less than 6 degrees C.
Soil moisture and cracks: when dry, the soils form cracks about 1 to 5 centimeters wide 10 to 36 centimeters apart at a depth of 20 to 91 centimeters and remain closed from about December until late March or early April and remain open the rest of the time.
Depth to lithic contact: 50 to 100 centimeters (20 to 40 inches).
Soil structure: Few or common wedge shape aggregates.
Slickensides: at a depth of 20 to 91 centimeters (8 to 36 inches).
Clay content: 60 to 70 percent.
Exchangeable sodium percentage (ESP): 15 or more below 40 centimeters.
Electrical conductivity (EC): 4 or more below 40 centimeters.
E horizon (where it occurs)
Texture: silt loam or cobbly silt loam.
Rock fragment content: 1 to 3 percent stones, 5 to 20 percent cobbles and 0 to 10 percent gravel.
Carbonates: some pedons have few masses of calcium carbonate in the upper 5 centimeters (2 inches).
A horizon
Dry color: 10YR 5/2, 5/3, 6/3, 7.5YR 5/2, 5/4 or 4/4
Moist color: 10YR 3/2, 4/2, 4/3, 7.5YR 3/2, or 3/4
Texture: clay.
Rock fragment content: 0 to 10 percent gravel.
Exchangeable sodium percentage: 0 to 10 percent
Electrical conductivity: 0 to 4 ds/m
Reaction: slightly acid to moderately alkaline.
B horizon
Dry color: 10YR 5/2, 5/3, 6/3, 7.5YR 5/2, 5/4 or 4/4.
Moist color: 10YR 3/2, 4/2, 4/3, 7.5YR 3/2, or 3/4.
Texture: clay
Rock fragment content: 0 to 10 percent gravel
Exchangeable sodium percentage: 20 to 35 percent
Electrical conductivity: 4 to 16 ds/m
Reaction: slightly acid to moderately alkaline
Gypsum: some pedons have masses of gypsum directly above the lithic contact.
COMPETING SERIES: There are no completing series.
GEOGRAPHIC SETTING:
Landscape: islands
Landform: terraces and hills
Slopes of 2 to 30 percent
Parent material: fine alluvium derived from mixed rock sources resting on hard fractured volcanic rock.
Elevations: 0 to 380 meters (0 to 1,150 feet)
Climate: maritime with mild dry foggy summers and mild moist usually clear winters.
Mean annual precipitation is about 245 millimeters (9.5 inches)
Frost-free season: about 365 days.
GEOGRAPHICALLY ASSOCIATED SOILS:
Eelpoint soils: have a thermic soil temperature class and are on similar landforms.
Eelcove soils: have a natric horizon and are on similar landforms.
Notspier soils: have a paralithic contact, are thermic and are on similar landforms.
Westshore soils: have a clayey-skeletal particle size class and are on marine terraces.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; runoff is slow or medium when the cracks are closed; low saturated hydraulic conductivity.
USE AND VEGETATION: Used mainly for military maneuvers and to a minor extent for wildlife habitat. The vegetation consists of slender oats, ripgut brome, mouse barley, desert thorn and Australian saltbush.
DISTRIBUTION AND EXTENT: Channel Islands Soil Survey, San Clemente Island; Southern California Mountain, 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. Source of name for San Clemente Island.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: the zone from a depth of 0 to 46 centimeters.
Slickensides: the zone from a depth of 20 to 91 centimeters.
Lithic contact: at a depth of 91 centimeters.
OSD revised during correlation of the San Clemente Island Interim Report in 2018.
ADDITIONAL DATA:
NASIS User Site/Pedon ID: 1982CA037SANCLEMENTE
Classified using the Twelfth Edition Keys to Soil Taxonomy (2014)
National Cooperative Soil Survey
U.S.A.