LOCATION BIGA NV

Established Series
Rev. TEB-MJZ-JVC-JBF
09/2017

BIGA SERIES

The Biga series consists of very deep, well drained soils that formed in alluvium derived from mixed igneous rocks, loess, and volcanic ash. Biga soils are on fan remnants. Slopes are 2 to 15 percent. The mean annual precipitation is about 125 mm and the mean annual temperature is about 12 degrees C.

TAXONOMIC CLASS: Clayey over loamy, smectitic over mixed, superactive, mesic Durinodic Natrargids

TYPICAL PEDON: Biga gravelly coarse sandy loam--rangeland. (Colors are for dry soil unless otherwise noted.) The soil surface is partially covered with 25 percent gravel.

A1--0 to 5 cm; pale brown (10YR 6/3) gravelly coarse sandy loam, brown (10YR 4/3) moist; weak thin platy structure; soft, very friable, nonsticky and nonplastic; few very fine roots; many fine vesicular and tubular pores; 20 percent gravel; moderately alkaline (pH 8.2); clear smooth boundary. (3 to 15 cm thick)

A2--5 to 10 cm; pale brown (10YR 6/3) coarse sandy loam, brown (10YR 4/3) moist; weak thin platy structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and few fine roots: many fine tubular pores; 5 percent gravel; moderately alkaline (pH 8.2); abrupt smooth boundary. (0 to 13 cm thick)

E--10 to 15 cm; very pale brown (10YR 7/3) loam, brown (10YR 4/3) moist; moderate thin platy structure; hard, very friable, slightly sticky and slightly plastic; few very fine and fine roots; many fine and medium vesicular pores; common uncoated sand grains; few fine distinct yellowish brown (10YR 5/6) masses of iron accumulation and few fine prominent black (10YR 2/1) masses of manganese accumulation; 5 percent gravel; strongly alkaline (pH 8.8); abrupt smooth boundary. (0 to 13 cm thick)

2Btnk1--15 to 25 cm; light brown (7.5YR 6/4) clay, brown (7.5YR 4/4) moist; strong fine columnar structure; hard, firm, very sticky and very plastic; many very fine and common fine exped roots; common fine tubular pores; common pressure cutans on faces on peds; secondary carbonates segregated as few fine filaments; 2 percent gravel; strongly effervescent; strongly alkaline (pH 9.0) clear smooth boundary. (8 to 15 cm thick)

2Btnk2--25 to 30 cm; light brown (7.5YR 6/4) clay, brown (7.5YR 4/4) moist; moderate fine prismatic structure; hard, firm, very sticky and very plastic; many very fine and common fine exped roots; common fine tubular pores; common pressure cutans on faces on peds; secondary carbonates segregated as common fine masses and few fine filaments; 5 percent gravel; strongly effervescent; strongly alkaline (pH 9.0); clear wavy boundary. (5 to 15 cm thick)

3Bqk1--30 to 51 cm; very pale brown (10YR 7/3) gravelly coarse sandy loam, yellowish brown (10YR 5/4) moist; weak thick platy structure; extremely hard, firm and brittle, slightly sticky and slightly plastic; root mat capping horizon and few very fine roots in matrix; few very fine tubular pores; continuous brittle matrix; secondary carbonates segregated as common fine seams; 15 percent gravel; strongly effervescent; strongly alkaline (pH 8.8); clear smooth boundary. (18 to 40 cm thick)

3Bqk2--51 to 66 cm; very pale brown (10YR 7/3) sandy loam, brown (10YR 5/3) moist; weak thin platy structure; hard, friable, slightly sticky and slightly plastic; common very fine roots; many very fine tubular pores; 30 percent hard, firm discontinuous weak silica cementation; secondary carbonates segregated as few fine seams; 5 percent gravel; violently effervescent; strongly alkaline (pH 8.6); clear smooth boundary. (0 to 25 cm thick)

3Bk--66 to 104 cm; very pale brown (10YR 7/3) gravelly coarse sandy loam, brown (10YR 5/3) moist; weak thin platy structure; slightly hard, very friable, nonsticky and nonplastic; common very fine and few fine roots; many fine interstitial pores; secondary carbonates segregated as common fine seams and filaments; 25 percent gravel; strongly effervescent; strongly alkaline (pH 8.6); clear wavy boundary. (0 to 50 cm thick)

3B'qk--104 to 152 cm; very pale brown (10YR 7/3) gravelly loamy coarse sand, brown (10YR 5/3) moist; moderate thin platy structure; slightly hard, friable, nonsticky and nonplastic; common very fine roots; many fine interstitial pores; 50 percent hard, firm discontinuous weak silica cementation; secondary carbonates segregated as common fine and medium masses on faces of peds; 20 percent gravel; noneffervescent matrix; moderately alkaline (pH 8.4).

TYPE LOCATION: Pershing County, Nevada; about 15 miles northwest of Toulon in Granite Springs Valley; approximately 600 feet east and 2,400 feet north of the southwest corner of section 19, T. 26 N., R. 27 E.; USGS Bluewing Spring 7.5 minute topographic quadrangle; latitude 40 degrees 06 minutes 28 seconds N and longitude 119 degrees 00 minutes 06 seconds W; WGS84 Decimal Degrees 40.1070556 latitude, -119.001667 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually dry; moist for short periods in late fall through early spring, dry late May through November; typic aridic soil moisture regime.
Mean annual soil temperature: 12 to 13 degrees C.
Depth to base of natric horizon: 30 to 50 cm.
Depth to strongly contrasting materials and horizons with firm, brittle matrix: 30 to 50 cm.
Depth to horizons with secondary carbonates; 10 to 28 cm.
Other features: Some pedons have C horizons below 100 cm.

Particle-size control Section - Clay content: 35 to 45 percent in the upper part and 2 to 10 percent in the contrasting lower part.
Rock fragments: 0 to 15 percent in the upper part and 5 to 30 percent in the lower part, fragments are mainly gravel of mixed igneous lithology such as granite and andesite.

A horizon
Value: 6 or 7 dry, 4 or 5 moist.
Chroma: 2 or 3, dry or moist.
Reaction: Slightly alkaline or moderately alkaline.

E horizon
Consistence: Soft to hard, nonsticky or slightly sticky, nonplastic or slightly plastic.
Reaction: Moderately alkaline or strongly alkaline.
Other features: Some pedons have few redox concentrations of iron and manganese which may be relict features; this horizon, when present, meets a criterion for albic materials and qualifies as an albic horizon.

2Btnk horizons
Hue: 7.5YR or 10YR.
Value: 5 or 6 dry, 4 or 5 moist.
Chroma: 3 through 6, dry or moist.
Texture: Clay, clay loam, or sandy clay.
Clay content: 35 to 45 percent.
Silt content: 5 to 15 percent.
Sand content: Mainly medium sand, coarse sand, and very coarse sand.
Rock fragments: 0 to 15 percent fine gravel.
Structure: Prismatic or columnar, parting to subangular blocky.
Consistence: Slightly hard or hard, moderately sticky or very sticky and moderately plastic or very plastic.
Reaction: Strongly alkaline or very strongly alkaline.
Salinity (EC): 2 to 8 mmhos/cm.
Sodicity (SAR): 13 to 45.

3Bq, 3Bk, and 3Bqk horizons
Value: 6 or 7 dry, 4 or 5 moist.
Chroma: 3 or 4, dry or moist.
Texture: Stratified sandy loam to gravelly loamy coarse sand.
Clay content: 2 to 10 percent.
Rock fragments: 5 to 25 percent fine gravel, less than 5 percent cobbles.
Structure: Platy or horizons are massive.
Consistence: Nonsticky or slightly sticky and nonplastic or slightly plastic.
Reaction: Moderately alkaline through very strongly alkaline.

COMPETING SERIES: There are currently no other series in this family.

GEOGRAPHIC SETTING: Biga soils are on fan remnants. They typically occur on summit positions. These soils formed in alluvium derived from mixed rocks, loess, and volcanic ash. Slopes are 2 to 15 percent. Elevations range from 1,160 to 1,525 meters. The climate is arid with cool, moist winters and hot, dry summers. The mean annual precipitation is 100 to 175 mm, the mean annual temperature is 11 to 13 degrees C, and the frost-free period is 120 to 130 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Deadyon, Granshaw, Labkey, and Shawave soils. Deadyon and Granshaw soils are coarse-loamy. Labkey soils are sandy-skeletal. Shawave soils are fine-loamy.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; medium surface runoff; moderately high saturated hydraulic conductivity.

USE AND VEGETATION: Biga soils are used for rangeland and wildlife habitat. The vegetation is mainly shadscale, Bailey's greasewood, bud sagebrush, and Indian ricegrass.

DISTRIBUTION AND EXTENT: Western Nevada. These soils are moderately extensive. MLRA 27.

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

SERIES ESTABLISHED: Pershing County (West Part), Nevada, 1988.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 15 cm (A1, A2, and E horizons).
Albic horizon - The zone from 10 to 15 cm (E horizon).
Natric horizon - The zone from 15 to 30 cm (2Btnk1 and 2Btnk2 horizons).
Duric feature - The zone from 30 to 66 cm (3Bqk1 and 3Bqk2 horizons).
Major lithologic discontinuity - The abrupt change to loamy material at 30 cm (3Bqk1, 3Bqk2, and 3Bk horizons).
Identifiable secondary carbonates - The zone from 15 to 152 cm (2Btnk1, 2Btnk2, 3Bqk1, 3Bqk2, 3Bk, and 3B'qk horizons).
Particle-size control section - The zone from 15 to 100 cm (2Btkn1, 2Btnk2, 3Bqk1, 3Bqk2 and part of the 3Bk horizons).

Minor errors in horizon designations corrected 9/2107.

National Cooperative Soil Survey
U.S.A.