LOCATION BONANZA                 CA

Established Series
JBB/TKK/JW
09/2018

BONANZA SERIES

The Bonanza series consists of shallow, well drained soils formed in residuum weathered from metavolcanic rocks. The Bonanza soils are on summits, shoulders, and backslopes of hills. Slopes range from 2 to 30 percent. The mean annual precipitation is about 580 mm and the mean annual air temperature is about 16 degrees C.

TAXONOMIC CLASS: Loamy, mixed, superactive, thermic, shallow Ultic Haploxeralfs

TYPICAL PEDON: Bonanza loam on a northeast facing, convex, 6 percent slope under blue oak savanna at an elevation of 235 meters. (Colors are for dry soils unless otherwise noted. When described on March 3, 2013 the soil was dry to a depth of 3 cm and moist beneath.)

A--0 to 6 cm; pale brown (10YR 6/3) loam, dark brown (10YR 3/3) moist; 12 percent clay; moderate fine granular structure; slightly hard, friable, nonsticky, nonplastic; common very fine roots throughout and few fine roots throughout; many very fine irregular pores; 5 percent subangular indurated metavolcanic gravel; moderately acid (pH 6.0); clear wavy boundary. (2 to 8 cm thick)

Bt1--6 to 20 cm; light yellowish brown (10YR 6/4) loam, dark yellowish brown (10YR 4/4) moist; 19 percent clay; moderate medium angular blocky structure; hard, very firm, slightly sticky, slightly plastic; common very fine and fine roots throughout; few very fine and fine tubular pores; 5 percent faint clay films on all faces of peds; 5 percent subangular indurated metavolcanic gravel; moderately acid (pH 5.6); gradual wavy boundary.

Bt2--20 to 45 cm; reddish yellow (7.5YR 6/6) gravelly loam, strong brown (7.5YR 5/6) moist; 22 percent clay; moderate fine subangular blocky structure; slightly hard, firm, slightly sticky, slightly plastic; few very fine, fine, and medium roots throughout; few very fine, fine and medium tubular pores; 10 percent distinct clay films on all faces of peds; 15 percent subangular strongly cemented metavolcanic gravel, 2 percent subangular strongly cemented metavolcanic cobbles; slightly acid (pH 6.2); clear wavy boundary. (combined thickness of the Bt horizons is 15 to 45 cm)

Cr--45 to 55 cm; moderately cemented metavolcanic bedrock, fractured at intervals of 10 to 45 cm. (5 to 25 cm thick)

R--55 to 65 cm; very strongly cemented metavolcanic bedrock.

TYPE LOCATION: Calaveras County, California, approximately 1.5 km (1 mile) northwest of the summit of Sugarloaf Mountain; USGS 7.5 minute topographic quadrangle: Knights Ferry, California; WGS84 37.864880 latitude and -120.664596 longitude; UTM zone 10 4193394 meters N 705432 meters E NAD83.

RANGE IN CHARACTERISTICS:
Soil temperature: The mean annual soil temperature at 50 cm is 16 to 18 degrees C and the difference between mean summer and mean 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 soil moisture regime.

Diagnostic Feature(s):
Ochric epipedon thickness: 3 to 20 cm
Argillic horizon thickness: 15 to 45 cm
Depth to paralithic contact: 25 to 50 cm
Depth to lithic contact: 40 to 70 cm

Base saturation: less than 75 percent in one or more subhorizons of the argillic horizon (by sum of cations)

Reaction: strongly to slightly acid


Particle size control section weighted average:
Rock fragments: 0 to 35 percent, with 0 to 20 percent gravel and 0 to 15 percent cobbles.
Clay content: 15 to 35 percent

A horizon
Hue: 7.5YR, 10YR
Value: 3 to 6 dry, 3 or 4 moist
Chroma: 4 or 6 dry, 3 or 4 moist
Texture: loam, silt loam
Clay content: 10 to 25 percent
Rock fragments: 0 to 15 percent
0 to 15 percent gravel
0 to 5 percent cobbles
Reaction: strongly acid to slightly acid

Bt horizon
Hue: 5YR, 7.5YR
Value: 4 to 7 dry, 3 to 5 moist
Chroma: 4 or 6 dry or moist
Texture: loam, silt loam, clay loam, silty clay loam
Clay content: 15 to 35 percent
Rock fragments: 0 to 35 percent
0 to 15 percent gravel
0 to 5 percent cobbles
Reaction: strongly to slightly acid

COMPETING SERIES: These are the Dunstone soils. Dunstone soils do not have a lithic contact within 25 cm of the paralithic contact.

GEOGRAPHIC SETTING: The Bonanza soils are on shoulders, summits, and backslopes on hills. Slopes range from 2 to 30 percent. These soils formed in residuum weathered from metavolcanic rocks. Elevation is 110 to 695 meters. The climate is Mediterranean with warm, dry summers and cool, moist winters. The mean annual precipitation is 410 to 915 mm and the mean annual air temperature is 15 to 17 degrees C. The frost free season is 225 to 335 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Auburn, Dunstone, Gopheridge, and Loafercreek soils. Auburn soils occur in similar landscape positions, but lack an argillic horizon and are less than 50cm to a lithic contact. Gopheridge soils have more than 35 percent rock fragments in the particle-size control section and occur on backslopes and footslopes. Loafercreek soils are 50 to 100cm to a paralithic contact and occur on backslops and footslopes. The competing Dunstone soils occur on toeslopes and lack a lithic contact within 25cm of the paralithic contact.

DRAINAGE AND PERMEABILITY: Well drained,saturated hydraulic conductivity is moderately high to high in the solum and low to high in the bedrock.

USE AND VEGETATION: This soil is used for grazing, recreation, wildlife habitat, homesite development, and watershed. Vegetation is blue oak savanna with annual grasses and forbs including soft brome, rose clover, broadleaf filaree, mouse barley, ripgut brome, and wild oat.

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

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

SERIES PROPOSED: Calaveras County, California. Source of name is from an historic mine in the area.

REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Ochric Epipedon 0 to 6 cm
Argillic Horizon 6 to 45 cm
Paralithic Contact 45 cm
Lithic Contact 55 cm
Particle Size Control Section for this pedon: 6 to 45 cm.

ADDITIONAL DATA:
NASIS User Pedon ID: 2013CA6303015
No certified laboratory data exists for this soil.

Soil classified using the 12th Edition of the Keys to Soil Taxonomy.

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National Cooperative Soil Survey
U.S.A.