LOCATION HUERHUERO               CA

Established Series
Rev. TCM/RLR
09/2020

HUERHUERO SERIES


The Huerhuero series consists of very deep, moderately well drained soils that formed in alluvium derived from material weathering from sandstone and other sedimentary rocks. Huerhuero soils are on old alluvial fans and marine terraces and have slopes of 0 to 30 percent. The mean annual precipitation is about 305 millimeters and the mean annual air temperature is about 17 degrees C.

TAXONOMIC CLASS: Fine, smectitic, thermic Typic Natrixeralfs

TYPICAL PEDON: Huerhuero soils in an area of Huerhuero loam on a slope of 6 percent facing west at an elevation of 20 meters under a cover of annual grasses. (Colors are for dry soil unless otherwise noted).

A1--0 to 20 centimeters; brown (10YR 5/3) loam, dark grayish brown (10YR 4/2) moist; massive; friable, hard, slightly sticky, slightly plastic; common very fine roots; many very fine tubular and interstitial pores; moderately acid (pH 5.6); abrupt smooth boundary. (10 to 58 cm thick)

A2--20 to 30 centimeters; pale brown (10YR 6/3) loam, brown (10YR 5/3) moist; massive; friable, hard, slightly sticky, slightly plastic; few very fine roots; common fine tubular pores; moderately acid (pH 5.7); abrupt smooth boundary. (1 to 18 cm thick)

Bt--30 to 48 centimeters; brown (10YR 5/3) clay, brown (10YR 4/3) moist; strong medium and coarse prismatic structure, strong medium angular blocky structure; firm, extremely hard, very sticky, very plastic; few very fine roots; many very fine and medium tubular pores; many distinct clay films on faces of peds; few slickensides; moderately alkaline (pH 8.0); clear smooth boundary.

Btkn--48 to 81 centimeters; brown (7.5YR 5/4) clay, brown (7.5YR 4/4) moist; strong medium prismatic structure, strong medium and fine angular blocky structure; firm, very hard, very sticky, very plastic; few very fine roots; many very fine and medium tubular pores; many distinct clay films on faces of peds; few slickensides; finely disseminated calcium carbonates and common medium calcium carbonate masses; moderately alkaline (pH 8.2); clear smooth boundary.

Btn1--81 to 104 centimeters; brown (7.5YR 4/2) clay, brown (7.5YR 4/2) moist; moderate medium prismatic structure, moderate medium and moderate fine angular blocky structure; firm, extremely hard, very sticky, very plastic; few very fine roots; few very fine tubular pores; few distinct clay films on faces of peds; moderately alkaline (pH 8.0); clear smooth boundary.

Btn2--104 to 140 centimeters; brown (7.5YR 5/2) clay loam, brown (7.5YR 4/2) moist; moderate medium and fine angular blocky structure; friable, hard, moderately sticky, moderately plastic; few very fine roots; common very fine and medium tubular pores; common distinct clay films on faces of peds; common manganese stains on ped faces; slightly alkaline (pH 7.8); clear smooth boundary.(Combined thickness of all Bt horizons 85 to 125 cm)

2BC--140 to 175 centimeters; brown (10YR 4/3) sandy loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; friable, hard, slightly sticky, slightly plastic, few very fine roots; slightly alkaline (pH 7.5); clear smooth boundary.

3C--175 to 210 centimeters; yellowish brown (10YR 5/4) loamy sand, dark yellowish brown (10YR 4/4) moist; massive; neutral; sandy marine sediments.

TYPE LOCATION: San Diego County, California; approximately 6 kilometers northwest of the City of Oceanside, about 375 meters east and 615 meters south of the northwest corner of section 32, T10S, R5W; 33.25461 degrees latitude, -117.43111 degrees longitude WGS84; UTM Zone 11, 3679596n, 459843e. U.S.G.S Quad Name: San Onofre Bluff, California

RANGE IN CHARACTERISTICS:
Mean annual soil temperature: 16 degrees C. Soil temperature is greater than 8 degrees C. the entire year.
Soil moisture: moist at a depth of 25 cm or more sometime from November or December and remains moist in some part until April or May.

Rock fragments: 0 to 5 percent gravels or cobbles throughout.
Reaction: moderately acid to moderately alkaline throughout.
Clay content: 35 to 45 percent by average in the particle-size control section.

A horizon:
Dry color: 10YR or 7.5YR 4/2, 5/2, 5/3, 5/4, 5/6 6/2, 6/3
Moist color: 10YR or 7.5YR 3/2, 3/3, 4/2, 4/4, 4/6, 5/3
Texture: very fine sandy loam, fine sandy loam, loam
Clay content: 8 to 25 percent
Rock fragments: 0 to 5 percent gravels
Organic matter content: less than 1 percent in the lower part

E Horizon: (where it occurs)
Dry color: 10YR 5/1, 6/1, 6/2, 6/3
Moist color: 10YR 4/1, 4/2, 5/1, 5/3
Texture: loam, very fine sandy loam
Clay content: 8 to 20 percent
Rock fragments:0 to 5 percent gravels

B horizons:
Dry color: 10YR, 7.5YR, 4/2, 4/4, 5/3, 5/4, 6/3, 6/4, or 5YR 5/3, 5/4
Moist color: 10YR, 7.5YR 4/2, 4/3, 4/4, 5/3, 5/4, 6/3, 6/4, or 5YR 4/3, 4/4
Texture: sandy clay loam, clay loam, or clay
Clay content: 35 to 45 percent
Rock fragments: 0 to 5 percent gravel
Exchangeable sodium percentage: 15 to 25 percent and is concentrated in the lower part of the horizon.
Sodium adsorption ratio: 13 to 25 percent and is concentrated in the lower part of the horizon.

Some pedons have a BC horizon with sandy loam texture.

C horizon
Dry color: 10YR 5/3, 5/4, 6/3
Moist color: 10YR 4/3, 4/4
Texture: loamy sand, sandy loam, very fine sandy loam and is typically stratified; some pedons have lenses of clay loam.
Exchangeable sodium percentage: 5 to 15 percent.
Sodium adsorption ratio: less than 13.

COMPETING SERIES:
Antioch soils: have redoximorphic features in the A horizon and typically have loam or clay loam textures in the C horizon.
Chicote soils: greater than 45 percent clay in the particle-size control section.
Placentia soils: greater than 20 percent coarse and very coarse sand in the particle-size control section.
Riz soils: strongly alkaline in the particle-size control section.
San Miguel soils: 50 to 100 centimeters to a lithic contact of metavolcanic rock.
Stockpen soils: greater than 45 percent clay in the particle-size control section.

GEOGRAPHIC SETTING:
Landscape: coastal plains and valleys and canyons
Landform: marine terraces and alluvial fans
Parent Material: alluvium derived from mostly sandstone or related sedimentary rocks
Slope: 0 to 30 percent slopes
Elevation: 0 to 515 meters
Mean annual precipitation: 250 to 450 mm
Mean January temperature: 13 degrees C.
Mean July temperature: 21 degrees C.
Mean annual temperature: 16.0 to 18.0 degrees C.
Frost-free season: 320 to 365 days

GEOGRAPHICALLY ASSOCIATED SOILS:
Carlsbad soils: sandy particle-size class over a duripan and are on similar landforms on marine terraces.
Chesterton soils: 100 centimeters to a duripan and are on similar positions on terraces
Linne soils: 90 to 150 cm to a paralithic contact of shale and are on adjacent hill slopes and mountain slopes.
Marina soils: have lamellae in the in the series control section and are on sand dunes.
Olivehain soils: clayey-skeletal particle-size class and are on dissected marine terraces.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Moderately-well or well drained; very slow saturated hydraulic conductivity.

USE AND VEGETATION: Used for small grain, truck crops, flowers and industrial and urban development. Native vegetation is soft chess, wild oats, filaree, redbrome, ripgut brome, buckwheat, and coastal California sage.

DISTRIBUTION AND EXTENT: Southern California Coastal Plains and Mountains, MLRA 19. This soil is moderately extensive.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Davis, California.

SERIES ESTABLISHED: San Diego County, California 1929.

REMARKS:

Diagnostic horizons and features recognized in this pedon include:
Ochric epipedon: the zone from 0 to 22 cm
Natric horizon: the zone from 30 to 140 cm
Particle-size control section: the zone from 30 to 80 cm

This series was reactivated in 2020 and updated to meet National Cooperative Soil Survey standards. The Huerhuero series was formerly combined with the Antioch series from Yuba County.

ADDITIONAL DATA:

NASIS User Site/Pedon ID: 1973CA073001

Classified using the Twelfth Edition Keys to Soil Taxonomy (2014)


National Cooperative Soil Survey
U.S.A.