LOCATION BICONDOA CA+NV OR

Established Series
Rev. TM/JBF
04/2018

BICONDOA SERIES

The Bicondoa series consists of very deep, poorly drained soils formed in clayey alluvium from tuff and basalt. Bicondoa soils are on floodplains and have slopes of 0 to 2 percent. The mean annual precipitation is about 230 mm and the mean annual temperature is about 6.7 degrees C.

TAXONOMIC CLASS: Fine, smectitic, calcareous, frigid Fluvaquentic Vertic Endoaquolls

TYPICAL PEDON: Bicondoa clay - meadow. (Colors are for dry soil unless otherwise stated).

A1--0 to 8 cm; gray (10YR 5/1) clay, very dark brown (10YR 2/2) moist; strong very fine granular structure; hard, friable, very sticky, very plastic; many very fine and fine roots; many very fine and fine interstitial pores; strongly effervescent; moderately alkaline (pH 8.4); clear smooth boundary. (5 to 8 cm thick)

A2--8 to 28 cm; gray (10YR 5/1) clay, black (10YR 2/1) moist; strong very fine granular structure; hard, friable, very sticky, very plastic; many very fine and fine roots; many very fine and fine interstitial, many very fine tubular pores; strongly effervescent; moderately alkaline (pH 8.4); clear wavy boundary. (15 to 30 centimeters thick)

Bw1--28 to 50 cm; gray (10YR 6/1) clay, very dark gray (10YR 3/1) moist; weak medium prismatic structure; hard, friable, very sticky, very plastic; common very fine and fine roots; many very fine and fine interstitial and tubular pores; few fine faint dark grayish brown (10YR 4/2) redox concentrations along root channels; strongly effervescent; moderately alkaline (pH 8.4); clear wavy boundary. (15 to 33 cm thick)

Bw2--50 to 69 cm; gray (10YR 6/1) clay, very dark gray (10YR 3/1) moist; weak medium prismatic structure; very hard, friable, very sticky, very plastic; common very fine and few fine roots; many very fine and few fine tubular pores; common coarse faint gray (N 5/) organic stains; noneffervescent; moderately alkaline (pH 8.2); clear wavy boundary. (8 to 25 cm thick)

C1--69 to 117 cm; gray (10YR 6/1) clay, very dark gray (10YR 3/1) moist; massive; very hard, firm, very sticky, very plastic; few very fine and fine roots; many very fine tubular pores; many medium and coarse distinct light gray (2.5Y 7/2) redox concentrations; common medium faint gray (N 5/) and dark gray (N 4/) organic stains; noneffervescent; moderately alkaline (pH 8.2); abrupt wavy boundary. (30 to 70 cm thick)

C2--117 to 157 cm; light gray (2.5Y 7/2) silty clay, grayish brown (2.5Y 5/2) moist; massive; hard, friable, very sticky, very plastic; few very fine roots; few very fine and fine tubular pores; common fine distinct yellowish brown (10YR 5/4) iron concentrations; common medium and coarse distinct gray (N 5/) and dark gray (N 4/) organic stains; noneffervescent; slightly alkaline (pH 7.6).

TYPE LOCATION: Modoc County, California; about 20 feet north of irrigation ditch and 25 feet west of fence on the Bare Ranch; 1,350 feet west and 400 feet north of the SE corner of sec. 34, T. 39 N., R. 17 E., Mount Diablo base line and meridian; USGS Snake Lake 7.5 minute topographic quadrangle; latitude 41 degrees 11 minutes 45.4 seconds N and longitude 120 degrees 01 minutes 30.8 seconds W; WGS84 Decimal Degrees 41.1959444 latitude, -120.0252222 longitude.

RANGE IN CHARACTERISTICS:

Soil moisture: Saturated between the soil surface and 45 cm during most years unless drained.
Mean annual soil temperature: 6 to 8 degrees C.
Mean summer soil temperature: 16 to 17 degrees C.
Mollic epipedon thickness: 25 to 50 cm.
Carbonates - Calcareous throughout most of their upper 50 cm (and are slightly calcareous to noncalcareous below the water table.
Reaction - Slightly alkaline or moderately alkaline but ranges to very strongly alkaline in sodic areas. pH values decrease with depth or remain constant.
Redoximorphic features - Redox concentrations and depletions with reddish or yellowish hue, neutral, low chroma, or high chroma are in the lower part of the A horizon or in any part of the Bw and C horizon. Where moist chroma of 2 is present with moist value of 3, the horizon immediately under the mollic epipedon has moist value of 3 or 4 and moist chroma of 1.

Particle size control section - Clay content: Averages 40 to 60 percent.

A horizon
Hue: 10YR or 2.5Y.
Value: 4 or 5 dry and 2 or 3 moist.
Chroma: 1 or 2.
Structure: Moderate or strong, very fine or fine granular or subangular blocky structure.
Organic matter: 2 to 4 percent

Bw horizon
Hue: 10YR or 2.5Y.
Value: 6 dry and 3 or 4 moist.
Chroma: 1 or 2.
Structure: Weak or moderate, medium or coarse, prismatic or subangular blocky structure.
Organic matter: 0.5 to 2 percent

C horizon
Hue: 10YR or 2.5Y, but ranges to 5Y in the lower C horizon.
Value: 6 or 7 dry and 3 through 5 moist.
Chroma: 1 to 4.
Other features: Redox depletions occur in the lower C horizon of some pedons. One or more buried A horizons, up to 20 centimeters thick, are present in some pedons.
Organic matter: 0.5 to 2 percent

COMPETING SERIES: There are no competing series at present.

GEOGRAPHIC SETTING: Bicondoa soils are on nearly level floodplains at elevations of 1,340 to 1,615 meters. Slopes are 0 to 2 percent. The soils formed in alluvium derived mostly from tuff and basalt. The climate is cool, semiarid. Mean annual precipitation is 175 to 300 mm. The mean annual temperature ranges from 6 to 8 degrees C, mean January temperature of about -2 to -3 degrees C, and mean July temperature of about 20.6 to 21 degrees C. The frost free period is 70 to 90 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Four Star, Hussa, and Kisring soils. Four Star soils have ashy control sections. Hussa soils have ashy control sections. Kisring soils lack a mollic epipedon and have a calcic horizon with durinodes.

DRAINAGE AND PERMEABILITY: Poorly drained; very slow runoff; slow permeability; moderately low saturated hydraulic conductivity class. Water table is above 46 cm except in drained phases.

USE AND VEGETATION: These soils are used for irrigated meadow production. The meadows are either cut for meadow hay or are grazed by livestock. Vegetation is predominantly rushes, sedges, and grasses in the less saline-sodic affected areas; and rushes, sedges, and salt grass in the more saline-sodic affected areas.

DISTRIBUTION AND EXTENT: Bicondoa soils have been recognized in Surprise Valley-Home Camp Area, California and Nevada; the Tuscarora Mountain Area, Nevada; the Diamond Valley Area, Nevada; and Lake County, Oregon, Southern Part. The soil is of moderate extent. MLRA 23 and 25.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California

SERIES ESTABLISHED: Surprise Valley-Home Camp Area, California and Nevada, 1971.

REMARKS: January, 2006, revision changes the classification from Fluvaquentic Endoaquolls to Fluvaquentic Vertic Endoaquolls.

Diagnostic horizons and features recognized in this pedon:
Mollic epipedon - zone from soil surface to 28 centimeters (A1, A2).
Cambic horizon - zone from 28 to 69 centimeters (Bw1, Bw2).
Vertic feature - calculated linear extensibility for the profile is 6.0 cm or higher.
Redoximorphic features -the zone from 8 to 157 cm (A2, B and C horizons).
ADDITIONAL DATA: Previous authors and reviewers include: LNL-LWW-SBJ-AJT

National Cooperative Soil Survey
U.S.A.