LOCATION SIERRA                  CA

Established Series


The Sierra series consists of deep to very deep, well drained soils that formed in material weathered from intrusive igneous rocks. Sierra soils are on foothills and have slopes of 0 to 70 percent. The mean annual precipitation is about 860 mm and the mean annual air temperature is about 15 degrees C.

TAXONOMIC CLASS: Fine-loamy, mixed, active, thermic Ultic Haploxeralfs

TYPICAL PEDON: Sierra coarse sandy loam - cultivated. (Colors are for dry soil unless otherwise noted.)

Ap--0 to 20 cm; brown (7.5YR 5/4) coarse sandy loam, dark reddish brown (5YR 3/4) moist; massive; slightly hard, friable; many very fine roots; many very fine and fine pores; moderately acid (pH 5.7); clear smooth boundary. (10 to 35 cm thick)

BAt--20 to 46 cm; reddish brown (5YR 5/4) loam, yellowish red (5YR 3/6) moist; massive; hard, friable, slightly sticky, slightly plastic; many very fine roots; many very fine, common fine, few medium and coarse pores; few thin discontinuous clay films line pores, colloids mainly bridging mineral grains; moderately acid (pH 5.9); gradual smooth boundary. (10 to 30 cm thick)

Bt1--46 to 69 cm; yellowish red (5YR 5/6) heavy loam, dark red (2.5YR 3/6) moist; massive; very hard, firm, slightly sticky, slightly plastic; common very fine roots; few medium coarse pores; clay films are thin and nearly continuous; slightly acid (pH 6.2); gradual smooth boundary. (15 to 25 cm thick)

Bt2--69 to 122 cm; red (2.5YR 5/6) clay loam, dark red (2.5YR 3/6) moist; massive; very hard, firm, sticky, plastic; common very fine roots- common very fine, few fine pores; moderately thick continuous clay films line most pores and as bridges between sand grains; slightly acid (pH 6.5); gradual smooth boundary. (20 to 75 cm thick)

BCt--122 to 173 cm; yellowish red (5YR 5/8) loam, dark red (2.5YR 3/8) moist; massive; very hard, firm, sticky, plastic; few very fine roots; common very fine and few fine pores; thin continuous clay films line some pores and as bridges between sand grains; slightly acid (pH 6.5); clear irregular boundary. (35 to 50 cm thick)

C--173 to 198 cm; yellowish red (5YR 5/8) weathered granite that textures fine sandy loam, yellowish red (5YR 3/8) moist, dark red (2.5YR 3/8 dry or moist) coatings; massive; original granitic structure is evident; hard, friable; thin discontinuous clay films along parting planes; slightly acid (pH 6.5).

TYPE LOCATION: Amador County, California; approximately 2 1/4 miles northwest of Fiddletown, 1/2 mile south of the Shenandoah School on the Shenandoah School road in SW1/4 SW1/4 sec. 29, T.8N., R.llE. WGS84 38.512779 latitude and -120.797775 longitude. UTM Zone 10 692006 meters E 4265010 meters N, NAD83.

Soil temperature: the mean annual soil temperature at 50 cm depth is 15 to 18 degrees C. The difference between mean summer and winter soil temperature is greater than 6 degrees C. The soils have a thermic temperature regime.

Soil moisture: the soil moisture control section is dry in all parts from about May to October. The soils have a xeric moisture regime.

Diagnostic Feature(s)
Ochric epipedon thickness: 5 to 40 cm
Argillic horizon thickness: 55 to 145 cm
Depth to paralithic contact: 100 to 200 cm

Particle size control section weighted averages:
Clay content: 18 to 35 percent
Rock fragments: 0 to 15 percent (mostly fine gravel)

A horizons:
Hue: 5YR, 7.5YR, 10YR
Value: 5 or 6 dry; 3 moist
Chroma 3 to 6 dry; 4 to 6 moist
Texture: coarse sandy loam, sandy loam, loam
Clay content: 10 to 23 percent
Rock fragments: 0 to 15 percent (mostly fine gravel)
Reaction: strongly acid to neutral

The A horizon lower boundary is gradual or there is a transitional horizon.

Bt horizon:
Hue: 2.5YR, 5YR
Value: 4 to 6 dry; 3 to 5 moist
Chroma: 4 to 8 dry or moist
Texture: loam, clay loam, sandy clay loam
Clay content: 20 to 40 percent
Coarse plus Very Coarse sand content: 15 to 25 percent
Rock fragments: 0 to 30 percent (gravel and cobbles)
Reaction: strongly acid to slightly acid

The Bt horizon has 50 to 75 percent base saturation (by ammonium acetate) in the upper 75 cm of the argillic horizon, increasing to 80 percent below this depth in some pedons.

COMPETING SERIES: These are the Coombs (MLRA 14), Craigsaddle, Flanly, Millvilla, Motherlode, Thompsonflat (MLRA 17), Verjeles, Wardsferry and Yellowlark (MLRA 17) soils. Coombs and Thompsonflat soils do not have a root-restrictive layer in the series control section and formed in mixed alluvium. Millvilla, Flanly and Verjeles have root-restrictive bedrock contacts within 100 cm. Craigsaddle soils are 100 to 150 cm to a densic contact. Motherlode soils are 100 to 150 centimeters to a lithic contact with metavolcanic rock. Wardsferry soils are 100 to 150 cm to a paralithic contact with metasedimentary rock. Yellowlark soils formed in mixed alluvium and are 100 to 150 centimeters to a duripan.

GEOGRAPHIC SETTING: The soils occur on backslopes of hill slopes at elevations of 225 to 1085 meters. The soils formed in residuum from intrusive igneous rocks. Rock outcrops occur in some areas. The climate is Mediterranean with hot, dry summers and cool, moist winters. Mean annual precipitation is 645 to 1140 mm, of which 1 to 5 percent occurs as snow. The average January air temperature is 6 degrees C, average July air temperature is 23 degrees C, and the mean annual air temperature is about 14 to 17 degrees C. Frost-free season is 205 to 330 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ahwahnee, Auberry, Auburn, Flanly, Verjeles and Whiterock soils. Ahwahnee, Auberry, and Flanly soils all occur on similar landform positions as Sierra. Ahwahneed soils have less than 18 percent clay in the particle size control section. Auberry soils have a paralithic contact at 100 to 150 cm depth and no hues redder than 7.5YR. Flanly and Verjeles are 50 to 100 cm to paralithic contact. Verjeles soils are moderately well drained, occur on footslope positions, and have clay textures in the lower part of the argillic horizon. Auburn and Whiterock soils have lithic bedrock contacts within 50 cm and occur on hills underlain by vertically-bedded metamorphic rock.

DRAINAGE AND PERMEABILITY: Well drained; Saturated hydraulic conductivity of the soil profile is moderately low to moderately high; Saturated hydraulic conductivity of the weathered bedrock is moderately low.

USE AND VEGETATION: Used for growing grain, grain hay and pasture and a few dryland orchards and vineyards. Under irrigation used for orchards, pasture and hay. Natural vegetation is annual weeds and grasses with interior live oak and blue oak, California foothill pine and scattered ponderosa pine.

DISTRIBUTION AND EXTENT: Sierra Nevada Foothills of California; MLRA 18. The soils are moderately extensive.


SERIES ESTABLISHED: Fresno Area, California, 1900.

Particle size control section recognized in this pedon: 20 to 70 cm

Diagnostic horizons and features recognized in this pedon:
Ochric epipedon: 0 to 20 cm
Argillic horizon: 20 to 173 cm

The Sierra soils were formerly classified as Noncalcic Brown soils.

NASIS User Pedon ID: S1959CA005016
Pedon Purpose: laboratory sampling location
Lab Source: Riverside SSL
Lab Pedon Number: 40A2909

The soil was classified using the 12th edition of the Keys to Soil Taxonomy.

National Cooperative Soil Survey