LOCATION YOMBA                   NV

Established Series
Rev. GAR/WED/RLB/JBF
06/2017

YOMBA SERIES

The Yomba series consists of very deep, somewhat excessively drained soils that formed alluvium derived from mixed rocks. Yomba soils are on alluvial flats, alluvial plains, fan piedmonts and, inset fans, fan skirts. Slopes are 0 to 4 percent. Mean annual precipitation is about 150 mm and mean annual temperature is about 12 degrees C.

TAXONOMIC CLASS: Sandy-skeletal, mixed, mesic Durinodic Haplocambids

TYPICAL PEDON: Yomba gravelly sand--rangeland. (Colors are for dry soil unless otherwise noted.)

A1--0 to 5 cm; light brownish gray (10YR 6/2) gravelly sand, very dark grayish brown (10YR 3/2) moist; single grained; loose, nonsticky and nonplastic; many very fine interstitial pores; 30 percent gravel; slightly alkaline (pH 7.6); abrupt smooth boundary. (3 to 10 cm thick)

A2--5 to 10 cm; light gray (10YR 7/2) fine sandy loam, dark grayish brown (10YR 4/2) moist; weak medium and thick platy structure; soft, very friable, nonsticky and nonplastic; few very fine, fine, and medium roots; many very fine and fine vesicular pores; slightly alkaline (pH 7.6); abrupt smooth boundary. (0 to 15 cm thick)

Bw--10 to 25 cm; light gray (10YR 7/2) fine sandy loam, dark grayish brown (10YR 4/2) moist; weak very coarse prismatic structure; soft, very friable, nonsticky and nonplastic; few very fine, fine, and medium roots; few very fine tubular pores; slightly alkaline (pH 7.4); abrupt wavy boundary. (8 to 30 cm thick)

Bk--25 to 36 cm; light gray (10YR 7/2) loam, brown (10YR 4/3) moist; weak coarse prismatic structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine, and few fine and medium roots; few very fine tubular pores; common medium and large distinct white (10YR 8/1) lime segregations; violently effervescent; moderately alkaline (pH 8.4); abrupt smooth boundary. (0 to 23 cm thick)

2Bqk--36 to 51 cm; light gray (10YR 7/2) gravelly coarse sandy loam , brown (10YR 4/3) moist; massive; hard and very hard, friable and firm, nonsticky and nonplastic; few fine and very fine roots; very fine tubular pores; few thin silica bridges between sand grains and lining pores; 30 percent gravel; common medium and large distinct white (10YR 8/1) lime masses; few medium and large prominent yellow (10YR 7/6) opal coats on discontinuous laminae; continuous brittle matrix; strongly effervescent; moderately alkaline (pH 8.2); abrupt wavy boundary. (14 to 38 cm thick)

3C--51 to 152 cm; gray (10YR 6/1) extremely gravelly sand, very dark grayish brown (10YR 3/2) moist; massive; soft, very friable, nonsticky and nonplastic; few very fine roots; many very fine and fine interstitial pores; 65 percent gravel; very few large distinct dark yellowish brown (10YR 4/4) iron concretions in 5 cm wide pockets; slightly alkaline (pH 7.8).

TYPE LOCATION: Nye County, Nevada; about 19 miles northwest of Tonopah and 2 miles west of Nevada Highway 89; about 1,000 feet east and 1,000 feet south of the northwest corner of section 25, T. 5 N., R. 40 E.; USGS San Antonio Ranch SW 7.5 minute topographic quadrangle; latitude 38 degrees 15 minutes 58 seconds N and longitude 117 degrees 26 minutes 19 seconds W; WGS84 Decimal Degrees 38.266222 latitude, -117.438611 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually dry, moist in some part for short periods during winters and early spring months, and for 10 to 20 days cumulative between July and October due to convection storms; typic aridic soil moisture regime.
Mean annual soil temperature: 12 to 15 degrees C.
Depth to 2Bqk horizon: 25 to 58 cm.
Depth to 3C horizon: 46 to 66 cm.

Particle-size control section - Clay content: Averages 3 to 8 percent.
Rock fragments: 40 to 60 percent, mainly gravel.

A horizon
Hue: 10YR or 2.5Y.
Value: 6 or 7 dry, 3 or 4 moist.
Chroma: 2 or 3.
Effervescence: Noneffervescent or slightly effervescent.
Reaction: Slightly alkaline or moderately alkaline.

Bw and Bk horizons
Hue: 10YR or 2.5Y.
Value: 6 or 7 dry, 3 or 4 moist.
Chroma: 2 or 3.
Texture: Sandy loam, fine sandy loam or loam.
Clay content: 10 to 20 percent.
Rock fragments: 0 to 15 percent, mainly gravel.
Consistence: Soft to slightly hard, nonsticky to sticky and nonplastic to plastic.
Effervescence: Strongly effervescent or violently effervescent.
Reaction: Slightly alkaline through strongly alkaline.
Structure: Platy, prismatic or subangular blocky.

2Bqk horizon
Value: 6 or 7 dry, 4 through 6 moist.
Chroma: 2 through 4.
Texture: Coarse sandy loam, sandy loam.
Rock fragments: 30 to 50 percent, dominantly gravel.
Consistence: Hard to very hard, friable to firm.
Effervescence: Strongly effervescent or violently effervescent.
Reaction: Moderately alkaline or strongly alkaline.
Other Features: Has laminae with cementation that ranges from weak with only a few thin silica bridges to strong with 0.6 cm thick discontinuous layers in pockets and seams.

3C horizon
Value: 6 or 7 dry, 3 through 5 moist.
Chroma: 1 through 3.
Texture: Sand, strata with variable percent of gravel and cobbles, dominantly gravel.
Rock fragments: Average 50 to 70 percent.
Effervescence: Noneffervescent or slightly effervescent.
Reaction: Slightly alkaline through strongly alkaline.

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

GEOGRAPHIC SETTING: Yomba soils are on alluvial flats, alluvial plains, fan piedmonts and fan skirts. These soils formed in mixed alluvium derived from rhyolite, basalt, granite, and tuff. Slopes are 0 to 4 percent. Elevations are 1,225 to 1,936 meters. The mean annual precipitation is 100 to 200 mm, the mean annual temperature ranges from 11 to 14 degrees C, and the frost-free season is 120 to 150 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Belcher, Domez and Stumble soils. Belcher soils are shallow over tuff. Domez soils are fine-loamy. Stumble soils are sandy.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat excessively drained; very slow to slow runoff; moderately high saturated hydraulic conductivity.

USE AND VEGETATION: Livestock grazing and wildlife habitat. The vegetation is principally Bailey greasewood, shadscale, Anderson wolfberry, graymolly and fourwing saltbush.

DISTRIBUTION AND EXTENT: South central Nevada. These soils are of moderate extent. MLRA 29.

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

SERIES ESTABLISHED: Nye County, Nevada, (Big Smoky Valley Area), 1972.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 18 cm (A1, A2 and part of Bw horizons).
Cambic horizon - The zone from 10 to 25 cm (Bw horizon).
Duric feature - The zone from 36 to 50 cm (2Bqk horizon).
Particle-size control section - The zone from 25 to 100 cm (Bk, 2Bqk and part of 3C horizons).

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National Cooperative Soil Survey
U.S.A.