LOCATION CENTINELA CA
Established Series
RLR/GML/RLR
02/2017
CENTINELA SERIES
The Centinela series consists of well drained soils that formed in a thin surface mantle of human-transport materials (HTM) overlying alluvium from marine or mixed rock sources. Centinela soils are on alluvial fans remnant, inset fans, fluviomarine bottoms and low lying terraces. Slopes range from 0 to 9 percent. The mean annual precipitation is about 342 mm and the mean annual air temperature is about 17.2 degrees C.
TAXONOMIC CLASS: Fine, smectitic, thermic Vertic Haploxerepts
TYPICAL PEDON: Centinela loam, on a low lying alluvial deposit on an irrigated city park lawn at an elevation of 18 meters. (Colors are dry soil unless otherwise noted.)
^A--0 to 7 cm; dark grayish brown (10YR 4/2) loam, very dark grayish brown (10YR 3/2) moist; friable, slightly hard, slightly sticky and slightly plastic; slightly alkaline (pH 7.4); abrupt smooth boundary. (2 to 35 cm thick)
^Cu--7 to 43 cm; pale brown (10YR 6/3) loam, 5 percent yellowish brown (10YR 5/6) and brown (10YR 4/3) moist; weak medium subangular blocky structure; friable, moderately hard, moderately sticky and moderately plastic; few artifacts; slightly alkaline (pH 7.6); few pockets of 10YR 5/6 from mechanical mixing; soil structure is remnant from source material; abrupt smooth boundary. (10 to 45 cm thick)
2Bss--43 to 95 cm; clay, very dark brown (10YR 2/2) moist; weak coarse prismatic structure; firm, very sticky and very plastic; common slickensides and many pressure faces on surfaces of peds; slightly alkaline (pH 7.8); gradual wavy boundary.
2Bkss--95 to 140 cm; clay, very dark grayish brown (10YR 3/2) moist; weak coarse prismatic structure; firm, very sticky and very plastic; common slickensides and many pressure faces on surfaces of peds; common fine irregular calcium carbonate masses; strongly effervescent; slightly alkaline (pH 7.8); gradual wavy boundary.(combined thickness of 2Bss horizons is 60 to 110 cm.)
2Bk--140 to 155 cm; clay loam, brown (10YR 5/3) moist; weak coarse subangular blocky structure; firm, very sticky and very plastic; common fine distinct dark yellowish brown (10YR 4/6) iron-manganese masses and common fine faint grayish brown (10YR 5/2) iron depletions; few fine irregular calcium carbonate masses; slightly effervescent; slightly alkaline (pH 7.8).
TYPE LOCATION: Los Angeles County, California; Jim Thorpe Park in grassy area between ballfield outfield fences; 33 degrees, 54 minutes, 15.62 seconds north latitude; 118 degrees 20 minutes, 33.36 seconds west longitude, WGS84 - U.S.G.S Quad: Inglewood.
RANGE IN CHARACTERISTICS:
Soil moisture: Moist below a depth of about 30 cm some time from October to December and remains moist in some part between depths of about 30 to 90 cm until April or May.
Mean annual soil temperature: 17 to 20 degrees C
Rock fragments: 0 to 5 percent
Reaction: slightly alkaline or moderately alkaline
Depth to secondary calcium carbonate: usually below 55 cm within the natural subsurface material; typically absent in the natural soil at the contact between HTM and natural subsoil.
Slickensides: occur within 75 cm of the surface, typically within 50 cm of the contact between the HTM with the natural subsoil
Clay content: greater than 35 percent in the particle-size control section
Thickness of human-transported materials: less than 50 centimeters thick
Artifacts: 0 to 10 percent construction debris in the HTM.
^A horizons:
Dry color: hue of 10YR, value of 2 to 6, chroma of 2 or 3
Moist color: hue of 10YR, value of 2 to 4, chroma of 1 to 3
Texture: loam, clay loam, sandy loam or silt loam
^C, ^Cu horizons: (if present)
Dry color: hue of 10YR, value of 2 to 6, chroma of 3 or 4
Moist color: hue of 10YR, value of 3 to 5, chroma of 2 to 4
Texture: loam, clay loam, sandy loam or silt loam
Artifacts: 0 to 10 percent.
(2)Bss(k) horizons:
Dry color: hue of 10YR; value of 2 to 5; chroma of 2 or 3
Moist color: hue of 10YR; value of 2 to 4; chroma of 2 or 3
Texture: clay, clay loam
(2)Bk horizons:
Dry color: hue of 10YR, value of 2 to 6, chroma of 2 to 4
Moist color: hue of 10YR, value of 2 to 5, chroma of 2 to 4
Texture: clay or clay loam
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Landscape: coastal plain and alluvial plains in urban areas
Landform: low lying alluvium, uplifted alluvium, terraces, or alluvial fans with slight to moderate surface modification
Slope: 0 to 9 percent
Parent material: alluvium from marine or mixed rock sources
Elevation: 0 to 150 meters
Mean annual precipitation is 280 to 420 mm
Mean January temperature: 14 degrees C
Mean July temperature: 21.5 degrees C
Mean annual temperature: 16 to 19 degrees C
Frost free season: 320 to 365 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Biscailuz soils: have less than 35 percent clay and are moderately-well drained and occur on similar landforms.
Cropley soils: have cracks at the surface during the summer and are on similar landforms.
Grommet soils: have 18 to 28 percent clay and are on alluvial fans from sedimentary sources.
Mocho soils: have 18 to 35 percent clay and have an irregular decrease in organic matter on similar landforms.
Ramona soils: have an argillic horizon and are on fan remnants from granitic sources
Sorrento soils: have 18 to 35 percent clay on similar landforms
Thums soils: have an argillic horizon and are on terraces and uplifted alluvium
Windfetch soils: have 18 to 35 percent clay and are on terraces and uplifted alluvium
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained and moderately well drained; medium to high runoff; low saturated hydraulic conductivity.
USE AND VEGETATION: Centinela soils are in high density urban residential and recreational areas. Vegetation is mostly non-native and ornamental.
DISTRIBUTION AND EXTENT: These soils are mapped in coastal plains and coastal interior valley of Southern California Coastal Plain; MLRA: 19. These soils are of moderate extent.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: City of Hawthorne, Los Angeles County, California, 2015
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone form a depth of 0 to 7 cm
Human transported material - the zone from a depth of 0 to 43 cm
Secondary calcium carbonate - the zone from a depth of 95 to 155 cm
Slickensides - the zone from a depth of 43 to 140 cm
Particle-size control section - the zone from a depth of 43 to 100 cm
Centinela soils are in urban areas that typically have a thin surface layer of human-transported materials. Soils that do not have surface modification are included in this concept.
The lithologic discontinuity separating the anthropogenic material and natural soil is not series criteria.
ADDITIONAL DATA:
NASIS User Pedon ID: 2014CA6961065.
Classified using the Twelfth Edition Keys to Soil Taxonomy (2014)
National Cooperative Soil Survey
U.S.A.