LOCATION BIDWELL CA+NVEstablished Series
TAXONOMIC CLASS: Ashy, glassy, mesic Vitritorrandic Argixerolls
TYPICAL PEDON: Bidwell ashy loam - cultivated. (Colors are for dry soil unless otherwise noted).
Ap1--0 to 10 centimeters; grayish brown (10YR 5/2) ashy loam, very dark grayish brown (10YR 3/2) moist; moderate medium and fine subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic; many very fine roots; many very fine interstitial and few very fine and fine tubular pores; neutral (pH 6.8); clear smooth boundary. (8 to 23 centimeters thick)
Ap2--10 to 25 centimeters; grayish brown (10YR 5/2) ashy clay loam, very dark grayish brown (10YR 3/2) moist; weak medium prismatic structure parting to moderate medium subangular blocky; hard, friable, moderately sticky, moderately plastic; many very fine roots; many very fine interstitial and common very fine and fine tubular pores; neutral (pH 6.8); clear wavy boundary. (8 to 18 centimeters thick)
Bt1--25 to 56 centimeters; grayish brown (10YR 5/2) ashy clay loam brown (10YR 4/3) moist; moderate medium subangular blocky structure; hard, friable, moderately sticky, moderately plastic; many very fine roots; many very fine interstitial and few very fine tubular pores; few thin clay films on faces of peds and many thin clay films lining pores; 10 percent gravel; neutral (pH 7.0); clear wavy boundary. (20 to 38 centimeters thick)
Bt2--56 to 81 centimeters; grayish brown (10YR 5/2) ashy clay loam, brown (10YR 4/3) moist; moderate medium subangular blocky structure; hard, friable, moderately sticky, moderately plastic; common very fine roots; common very fine and fine tubular and many very fine interstitial pores; few thin clay films on faces of peds and many thin clay films lining pores; neutral (pH 7.2); clear wavy boundary. (10 to 30 centimeters thick)
Btk--81 to 117 centimeters; brown (10YR 5/3) gravelly ashy loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; hard, friable, slightly sticky, slightly plastic; common very fine roots; few very fine tubular and many very fine interstitial pores; few thin clay films on faces of peds and lining pores; few fine lime segregations; 25 percent gravel; slightly alkaline (pH 7.6); clear wavy boundary. (8 to 36 centimeters thick)
Bk--117 to 185 centimeters; pale brown (10YR 6/3) gravelly ashy loam, brown (10YR 4/3) moist; massive; very hard, friable, slightly sticky, slightly plastic; few very fine roots; few very fine tubular and common very fine interstitial pores; 25 percent gravel; noncalcareous in matrix, strongly calcareous in common fine distinct lime segregations; moderately alkaline (pH 8.2).
TYPE LOCATION: Modoc County, California; 1.25 miles north of junction of California Highway 299 and the Surprise Valley road; about 1,400 feet north and 1,400 feet west of SE corner sec. 32, T. 43 N., R. 16 E; 41 degrees, 32 minutes, 51.2 seconds north latitude and 120 degrees, 10 minutes, 03.4 seconds west longitude, NAD 1927; Cedarville quadrangle.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually dry, moist in winter and spring. Aridic bordering xeric soil moisture regime.
Soil temperature - 8 to 11 degrees C (47 to 52 degrees F).
Mollic epipedon - 25 to 41 cm (10 to 16 inches) thick.
Depth to calcium carbonate - 50 to 100 cm (20 to 40 inches).
Depth to the base of the argillic horizon - 76 to 122 cm (30 to 48 inches).
Control Section
Clay content: 18 to 35 percent.
Rock fragments: 0 to 10 percent gravel. Lithology of the fragments is mostly tuff.
A horizon
Value: 4 or 5 dry.
Chroma: 1 or 2.
Structure: Moderate or strong, platy, granular or subangular blocky structure. Organic matter: 1 to 3 percent.
Bt horizon
Value: 3 or 4 moist.
Chroma: 1 to 3.
Texture: Ashy loam or ashy clay loam.
Rock fragments: 0 to 10 percent gravel.
Structure: Moderate or strong prismatic, angular blocky or subangular blocky structure.
Reaction: Slightly acid to moderately alkaline and becomes more alkaline as depth increases.
Btk horizon
Value: 5 or 6 dry.
Chroma: 3 or 4.
Clay content: 18 to 27 percent.
Rock fragments: 0 to 30 percent.
Carbonates: Lime segregations are less than 5 percent of any horizon.
Reaction: Slightly alkaline or moderately alkaline.
Bk horizon
Value: 5 or 6 dry.
Chroma: 3 or 4.
Texture: Ashy loam or ashy sandy loam.
Clay content: 10 to 27 percent.
Rock fragments: 5 to 35 percent.
Structure: Massive or has weak fine or medium subangular blocky structure.
Carbonates: Lime segregations are less than 5 percent of any horizon.
Reaction: Slightly alkaline or moderately alkaline.
COMPETING SERIES: These are the Ashone (NV), Coppersmith (CA), Ponyspring (NV) and Simpson (CA) series. Ashone soils are moderately deep to weathered tuff. Coppersmith soils have depth ranging from 30 to 61 cm (12 to 24 inches) to the base of the argillic horizon and have Bq horizons with 20 to 70 percent durinodes. Ponyspring soils are intermittently moist in the summer for 10 to 20 days due to convection storms and have 15 to 35 percent gravel in the control section. Simpson soils have a mollic epipedon thickness of 50 to 69 centimeters (20 to 27 inches).
GEOGRAPHIC SETTING: Bidwell soils are on fan remnants and fan skirts at elevations of 1,362 to 1,524 meters (4,470 to 5,000 feet). They formed in ashy alluvium from tuffaceous rocks. Slopes range from 0 to 8 percent. The climate is cool semiarid with warm dry summers and cool moist winters. Mean annual precipitation is about 305 to 406 mm (12 to 16 inches). Mean annual temperature is 7.2 to 9.4 degrees C (45 to 49 degrees F). The frost-free period is about 80 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Buntingville, Donica, Hussa, and Simpson series. Buntingville and Hussa soils are wet and have mottles within 50 centimeters of the surface. Donica soils lack an argillic horizon. Simpson soils have more than 35 percent clay in the argillic horizon.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderately slow permeability; moderately high saturated hydraulic conductivity class.
USE AND VEGETATION: These soils are used for rangeland and cropland. Uncultivated areas have a cover of big sagebrush, antelope bitterbrush, and bluebunch wheatgrass.
DISTRIBUTION AND EXTENT: Northeastern California. The soil is of moderate extent. MLRA 21 AND 23.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Surprise Valley-Home Camp Area, California-Nevada, Modoc County, California, 1971.
REMARKS: This soil is reclassified in January, 2006, based on glass counts. The former classification was fine-loamy, mixed, superactive, mesic Calciargidic Argixerolls.
Diagnostic horizons and features in this pedon include:
Mollic epipedon: The zone from 0 to 25 cm (0 to 10 inches) (Ap1 and Ap2 horizons).
Argillic horizon: The zone from 25 to 117 cm (10 to 46 inches) (Bt1, Bt2 and Btk horizons).
Ashy particle-size substitute class and glassy mineralogy: 30 to 50 percent glass and glass aggregates by grain count throughout the profile.
Particle-size control section: The zone from 25 to 76 cm (10 to 30 inches) (Bt1 and part of the Bt2 horizons).