LOCATION BENIN                   NV

Established Series
Rev. LIL-DLJ-JVC-JBF
02/2016

BENIN SERIES

The Benin series consists of very deep, well drained soils that formed in alluvium derived from mixed rocks and loess high in volcanic ash over lacustrine deposits. Benin soils are on lake terraces, dissected lake plains and basin floor remnants. Slopes are 0 to 4 percent. The mean annual precipitation is about 180 mm and the mean annual temperature is about 9 degrees C.

TAXONOMIC CLASS: Fine, smectitic, calcareous, mesic Vertic Torriorthents

TYPICAL PEDON: Benin silt loam--rangeland. (Colors are for dry soil unless otherwise noted.)

A--0 to 8 cm; light gray (2.5Y 7/2) silt loam, grayish brown (2.5Y 5/2) moist; weak medium and thin platy structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine roots; many very fine and fine vesicular pores; slightly effervescent; strongly alkaline (pH 8.6); abrupt smooth boundary. (3 to 18 cm thick)

C--8 to 20 cm; very pale brown (10YR 7/3) silt loam, brown (10YR 5/3) moist; weak fine granular structure; slightly hard, friable, slightly sticky and moderately plastic; many very fine and few fine roots; many very fine and fine tubular and common very fine vesicular pores; few thin silica films lining pores and common silica bridges and thin coatings on sand grains; slightly effervescent; strongly alkaline (pH 8.6); clear smooth boundary. (0 to 28 cm thick)

2Ck--20 to 58 cm; very pale brown (10YR 8/3) silty clay, pale brown (10YR 6/3) moist; strong medium angular blocky structure; extremely hard, extremely firm, moderately sticky and moderately plastic; common very fine and fine roots between peds; loose soil material between peds; common ostracod shells; 15 percent of the faces of peds are coated with very dark brown (10YR 2/2) manganese oxide masses which are relict redoximorphic features; 70 percent of the faces of peds are coated with pale yellow (2.5Y 8/2) masses of secondary carbonates; slightly effervescent matrix and violently effervescent masses; very strongly alkaline (pH 9.2); clear wavy boundary. (25 to 74 cm thick)

3Cy--58 to 84 cm; light gray (2.5Y 7/2) silty clay, grayish brown (2.5Y 5/2) moist; weak medium prismatic structure that parts to strong medium and fine angular blocky; extremely hard, extremely firm, very sticky and very plastic; many very fine and fine roots between peds; many very fine and fine exped pores; many ostracod shells; 75 percent of faces of peds have thin manganese masses which are relict redoximorphic features; 15 percent of the faces of peds have white gypsum crystals; strongly effervescent; strongly alkaline (pH 8.7); clear wavy boundary. (0 to 30 cm thick)

3C1--84 to 137 cm; light brownish gray (2.5Y 6/2) silty clay, grayish brown (2.5Y 5/2) moist; strong coarse prismatic structure; extremely hard, extremely firm, very sticky and very plastic; few roots between peds; many ostracod shells; continuous thin very dark gray (7.5YR 3/1) manganese masses on faces of peds which are relict redoximorphic features; strongly effervescent; moderately alkaline (pH 8.4); clear wavy boundary. (38 to 60 cm thick)

3C2--137 to 178 cm; light gray (2.5Y 7/2) silty clay, grayish brown (2.5Y 5/2) moist; strong coarse prismatic structure; extremely hard, extremely firm, very sticky and very plastic; few very fine roots between peds; common fine and medium, yellowish brown (10YR 5/6) masses of iron accumulation, 60 percent of faces of peds have a thin coating of very dark gray (7.5YR 3/1) manganese masses, and few medium and coarse yellowish brown (10YR 5/6) cylindrical nodules that appear to be high in iron which are relict redoximorphic features; strongly effervescent; moderately alkaline (pH 8.2).

TYPE LOCATION: Humboldt County, Nevada; about 8 miles southwest of Winnemucca and immediately northwest of the Winnemucca airport; approximately 900 feet south of the northwest corner of section 15, T. 35 N., R. 37 E.; USGS Winnemucca West 7.5 minute topographic quadrangle; latitude 40 degrees 54 minutes 51 seconds N and longitude 117 degrees 48 minutes 50 seconds W; WGS84 Decimal Degrees 40.9141667 latitude, -117.8138889 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually intermittently moist in winter and spring, dry in summer and fall; typic aridic soil moisture regime.
Mean annual soil temperature: 8 to 14 degrees C.
Depth to lacustrine deposits: 3 to 25 cm.
Salinity (EC): 4 to 32 mmhos/cm.
Sodicity (SAR): 13 to 440 at some depth between 3 and 90 cm.
Linear extensibility (LE): 6 to 9 cm.

Particle-size control section - Clay content:

A horizon
Value: 6 or 7 dry.
Chroma: 1 through 3, dry or moist.
Reaction: Moderately alkaline through very strongly alkaline.
Effervescence: Noneffervescent through violently effervescent.

C horizon (when present)
Hue: 10YR or 2.5Y.
Value: 6 or 7 dry, 4 or 5 moist.
Chroma: 2 or 3, dry or moist.
Texture: Silt loam or loam.
Reaction: Moderately alkaline or strongly alkaline.
Effervescence: Noneffervescent through violently effervescent.
Gypsum content: Secondary gypsum is common in some pedons in amounts up to 5 percent by weight.

2Ckn, 2Cyn, and 3C horizons
Hue: 10YR through 5Y.
Value: 6 through 8 dry, 4 through 6 moist.
Chroma: 2 or 3, dry or moist.
Texture: Silty clay or clay.
Structure: Weak through strong, medium or coarse prismatic that commonly parts to strong medium or coarse angular blocky or granular; or this horizon is massive.
Consistence: Hard to extremely hard dry, friable to extremely firm moist, moderately sticky to very sticky and moderately plastic to very plastic.
Reaction: Moderately alkaline through very strongly alkaline.
Calcium carbonate equivalent: 0 to 20 percent; individual subhorizons have less than 5 percent by volume identifiable secondary carbonates or less than 15 percent calcium carbonate equivalent.
Gypsum content: Secondary gypsum is common in some subhorizon of most pedons in amounts up to 5 percent by weight.
Other features: Most pedons have common to many relict redox concentrations of manganese or iron; some pedons have few to many silica coats on ped faces; some pedons have up to 10 percent durinodes;

COMPETING SERIES: These are the Dedmount, Lahontan, and Torchlight series.

Dedmount soils have mean annual soil temperature of 12 to 15 degrees C. Lahontan soils do not have gypsum crystals and are not influenced by loess high in volcanic ash in the upper part. Torchlight soils are moister in summer months.

GEOGRAPHIC SETTING: Benin soils are on smooth, nearly level or slightly concave dissected lake terraces, lake plains, and basin floor remnants. These soils formed in alluvium derived from mixed rocks and loess high in volcanic ash over lacustrine deposits. Slopes are 0 to 4 percent. Elevations range from 1,130 to 1,895 meters. The climate is arid with cool, moist winters and warm, dry summers. The mean annual precipitation is 150 to 230 mm, the mean annual temperature is 7 to 13 degrees C, and the frost-free period is 100 to 130 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Prida, Raglan, and Zorravista soils. Prida soils are fine-silty. Raglan soils fine-loamy and have horizons with durinodes. Zorravista soils are sandy and occur on dunes.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; very low or negligible surface runoff; low saturated hydraulic conductivity. These soils are typically nonflooded, but some phases are subject to occasional or frequent, very brief periods of flooding between November and June.

USE AND VEGETATION: Benin soils are used for rangeland and wildlife habitat. The present vegetation is mainly shadscale, bud sagebrush, black greasewood, and bottlebrush squirreltail.

DISTRIBUTION AND EXTENT: Western and central Nevada. These soils are moderately extensive. MLRAs 24, 27, and 28B.

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

SERIES ESTABLISHED: Humboldt County, Nevada (BLM Sonoma Planning Unit), 1974.

REMARKS: The revision of January 2004 updated the taxonomic class from Fine, smectitic, calcareous, mesic Typic Torriorthents based on linear extensibility values in the NASIS database.

Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 18 cm (A and part of the C horizons)
Identifiable secondary carbonates - The zone from 20 to 58 cm (2Ck horizon).
Particle-size control section - The zone from 25 to 100 cm (3Cy horizon and parts of the 2Ck and 3C1 horizons).

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National Cooperative Soil Survey
U.S.A.