LOCATION GWENA                   NV

Established Series
Rev. MJZ-RLB-JBF
03/2016

GWENA SERIES

The Gwena series consists of shallow, well drained soils that formed in alluvium derived from mixed rocks with some influence from loess and volcanic ash. Gwena soils are on fan-piedmont remnants. Slopes are 4 to 15 percent. The mean annual precipitation is about 250 mm and the mean annual temperature is about 9 degrees C.

TAXONOMIC CLASS: Loamy, mixed, superactive, mesic, shallow Xeric Natridurids

TYPICAL PEDON: Gwena very fine sandy loam--rangeland. (Colors are for dry soil unless otherwise noted.)

A1--0 to 5 cm; pale brown (10YR 6/3) very fine sandy loam, brown (10YR 4/3) moist; weak very thin platy structure; slightly hard, very friable, slightly sticky and slightly plastic; few very fine roots; many very fine vesicular pores; slightly alkaline (pH 7.8); clear smooth boundary. (3 to 8 cm thick)

A2--5 to 10 cm; pale brown (10YR 6/3) very fine sandy loam, brown (10YR 5/3) moist; moderate very thin platy structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; common very fine tubular pores; moderately alkaline (pH 8.0); clear smooth boundary. (5 to 10 cm thick)

AB--10 to 23 cm; pale brown (10YR 6/3) very fine sandy loam, brown (10YR 4/3) moist; moderate fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; common very fine tubular pores; moderately alkaline (pH 8.0); clear smooth boundary. (0 to 13 cm thick)

Btn--23 to 30 cm; light yellowish brown (10YR 6/4) clay loam, dark yellowish brown (10YR 4/4) moist; moderate fine prismatic structure; hard, firm, moderately sticky and moderately plastic; common very fine roots; common very fine tubular pores; very few faint clay films on ped faces; moderately alkaline (pH 8.4); clear smooth boundary. (8 to 20 cm thick)

Btnk--30 to 43 cm; light yellowish brown (10YR 6/4) clay loam, dark yellowish brown (10YR 4/4) moist; strong fine prismatic structure; hard, firm, moderately sticky and moderately plastic; few very fine roots; common very fine tubular pores; few faint clay films on ped faces; few fine carbonate filaments, strongly effervescent; strongly alkaline (pH 8.9); abrupt wavy boundary. (8 to 13 cm thick)

Bqk--43 to 48 cm; very pale brown (10YR 8/4) clay loam, brownish yellow (10YR 6/6) moist; massive; very hard, very firm, moderately sticky and moderately plastic; few very fine roots; common very fine tubular pores; strong discontinuous cementation; violently effervescent; strongly alkaline (pH 8.9); clear smooth boundary. (0 to 5 cm thick)

Bqkm--48 to 89 cm; very pale brown (10YR 8/3) indurated duripan, light yellowish brown (10YR 6/4) moist; massive; extremely hard, extremely firm; thin continuous laminar capping surface; violently effervescent; strongly alkaline (pH 8.8); clear irregular boundary. (15 to 43 cm thick)

2B'qk--89 to 132 cm; light gray (10YR 7/2) extremely gravelly sandy loam, light yellowish brown (10YR 6/4) moist; massive; hard, firm, nonsticky and nonplastic; few very fine tubular pores; alternating layers of weak and strong discontinuous silica and carbonate cementation; 70 percent gravel, 5 percent cobbles; carbonate coatings on undersides of rock fragments; strongly effervescent; strongly alkaline (pH 8.6); clear smooth boundary. (15 to 46 cm thick)

2C--132 to 152 cm; very pale brown (10YR 7/4) very gravelly loamy coarse sand, yellowish brown (10YR 5/6) moist; single grained; loose, nonsticky and nonplastic; common very fine tubular pores; 55 percent gravel; strongly effervescent carbonate coatings on undersides of gravel; noneffervescent matrix; strongly alkaline (pH 8.6).

TYPE LOCATION: Pershing County, Nevada; approximately 13 miles northeast of Imlay, about 500 feet west and 1,200 feet south of the northeast corner of section 28, T. 33 N., R. 36 E.; USGS Dun Glen 7.5 minute topographic quadrangle; latitude 40 degrees 42 minutes 31 seconds N and longitude 117 degrees 55 minutes 46 seconds W; WGS84 Decimal Degrees 40.7086111 latitude, -117.9294444 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Moist in winter and spring, dry June through November; aridic soil moisture regime that borders on xeric.
Mean annual soil temperature: 8 to 11 degrees C.
Depth to duripan: 36 to 50 cm.

Particle-size control section - Clay content: 20 to 35 percent.
Rock fragments: Average less than 15 percent, mainly gravel.

A horizon
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 2 or 3.
Consistence: Soft or slightly hard dry, nonsticky or slightly sticky moist and nonplastic or slightly plastic wet.
Reaction: Slightly alkaline or moderately alkaline.

Bt horizon
Hue: 10YR or 7.5YR.
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 3 or 4.
Texture: Loam or clay loam.
Clay content: 20 to 35 percent.
Rock fragments: Some pedons have subhorizons with up to 25 percent gravel.
Structure: Prismatic or subangular blocky.
Consistence: Slightly sticky or sticky and slightly plastic or plastic wet.
Reaction: Moderately alkaline or strongly alkaline.
Exchangeable sodium: 20 to 35 percent.

Bqkm horizon
Value: 6 through 8 dry, 4 through 6 moist.
Chroma: 2 through 6.
Structure: Platy or is massive.
Other features: Thickness of the duripan ranges from 15 to 43 cm.

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

GEOGRAPHIC SETTING: Gwena soils are on fan-piedmont remnants. These soils formed in alluvium derived from mixed rock sources with some influence from loess and volcanic ash. Slopes are 4 to 15 percent. Elevations are 1,400 to 2,000 meters. The climate is cool, semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 200 to 300 mm, mean annual temperature is 8 to 11 degrees C, and the frost-free season is 100 to 120 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bliss and Enko series. Bliss soils have cambic horizons and a strongly cemented duripans below 51 cm. Enko soils have cambic horizons and a continuous weak silica cemented subhorizon.

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

USE AND VEGETATION: Rangeland and wildlife habitat. The present vegetation is mainly Wyoming big sagebrush, spiny hopsage, Thurber needlegrass, bottlebrush squirreltail, and Sandberg bluegrass.

DISTRIBUTION AND EXTENT: North-central and central Nevada. These soils are not extensive. MLRA 24, 27.

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

SERIES ESTABLISHED: Pershing County, Nevada, East Part. 1986.

REMARKS: Diagnostic features and horizons recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 23 cm (A1, A2 and AB horizons).
Natric horizon - The zone from 23 to 43 cm (Btn, Btnk horizons).
Indurated duripan - The zone from 48 to 89 cm (Bqkm horizon).
Particle-size control section - The zone from 23 to 43 cm (Btn, Btnk horizons).

---

National Cooperative Soil Survey
U.S.A.