LOCATION POKERGAP                NV

Established Series
Rev. TEB/RLB/JBF
05/2016

POKERGAP SERIES

The Pokergap series consists of very deep, well drained soils that formed in alluvium derived from mixed rocks including loess and volcanic ash. The Pokergap soils are on fan piedmont remnants and mountain valley fans. Slopes are 2 to 30 percent. The mean annual precipitation is about 230 mm and the mean annual temperature is about 10 degrees C.

TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Durinodic Xeric Natrargids

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

A1--0 to 5 cm; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; moderate medium platy structure; slightly hard, very friable, moderately sticky and slightly plastic; few very fine roots; many very fine, common fine and medium vesicular and few very fine tubular pores; 10 percent gravel; moderately alkaline (pH 8.2); abrupt wavy boundary. (3 to 8 cm thick)

A2--5 to 15 cm; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; weak thin platy structure soft, very friable, moderately sticky and slightly plastic many very fine and few fine roots many very fine and few fine tubular pores; 2 percent gravel; moderately alkaline (pH 8.2); clear smooth boundary. (5 to 10 cm thick)

2Bt--15 to 23 cm; light yellowish brown (10YR 6/4) clay loam, dark yellowish brown (10YR 4/4) moist; weak fine subangular blocky structure; hard, friable, moderately sticky and moderately plastic; many very fine, few fine and medium roots; common very fine tubular pores; common thin clay films on faces of ped and lining pores; 10 percent gravel; moderately alkaline (pH 8.2); clear smooth boundary. (8 to 15 cm thick)

2Btn--23 to 36 cm; light yellowish brown (10YR 6/4) gravelly clay loam, dark yellowish brown (10YR 4/4) moist; moderate medium prismatic structure; hard, firm, moderately sticky and moderately plastic; many very fine and few fine roots; common very fine tubular pores; many thin clay films on faces of ped and lining pores; 15 percent gravel; matrix dominantly noneffervescent with a few slightly effervescent spots; strongly alkaline (pH 8.6); clear wavy boundary. (10 to 20 cm thick)

2Bqk1--36 to 53 cm; very pale brown (10YR 7/3) gravelly loam, yellowish brown (10YR 5/4) moist; massive; hard, friable, slightly sticky and plastic; few very fine and fine roots; few very fine tubular pores; 20 percent weakly silica cemented 2 to 5 mm durinodes; few fine carbonate filaments; thin carbonate coats on undersides of gravel; 20 percent gravel; violently effervescent; moderately alkaline (pH 8.3); abrupt smooth boundary. (15 to 25 cm thick)

2Bqk2--53 to 81 cm; very pale brown (10YR 7/3) very gravelly sandy loam, brown (10YR 5/3) moist; massive; hard, firm and brittle, slightly sticky and nonplastic; common very fine and few fine roots; few very fine tubular pores; continuous weak silica cementation with a thin discontinuous opal laminae at the upper boundary; thin carbonate coats on undersides of gravel; 35 percent gravel; violently effervescent; strongly alkaline (pH 8.8); abrupt wavy boundary. (20 to 36 cm thick)

3Bqk3--81 to 109 cm; very pale brown (10YR 8/2) extremely gravelly coarse sandy loam, light yellowish brown (10YR 6/4) moist; moderate medium platy structure; hard, firm, and brittle, nonsticky and nonplastic; common very fine and few fine roots mainly between plates; few very fine tubular pores; continuous weak silica cementation; carbonate coats on all sides of rock fragments and pendants on undersides; 60 percent gravel, 10 percent cobbles, 5 percent stones; violently effervescent; strongly alkaline (pH 8.6); clear smooth boundary. (20 to 46 cm thick)

3Bqk4--109 to 127 cm; pale brown (10YR 6/3) very gravelly coarse sandy loam, brown (10YR 4/3) moist; massive; hard, firm, nonsticky and nonplastic; few very fine roots; common very fine tubular pores discontinuous weak silica cementation; common fine carbonate filaments and medium soft masses; thin carbonate coats on undersides of gravel; 55 percent gravel, 2 percent cobbles, 1 percent stones; violently effervescent; strongly alkaline (pH 8.6); gradual smooth boundary. (0 to 30 cm thick)

3Bk--127 to 152 cm; pale brown (10YR 6/3) extremely gravelly loamy coarse sand, brown (10YR 4/3) moist; massive; hard, friable, nonsticky and nonplastic; common very fine, few fine and medium roots; common very fine tubular pores; violently effervescent; common fine carbonate filaments; thin carbonate and silica coats on all sides of rock fragments; 65 percent gravel, 5 percent cobbles; strongly alkaline (pH 8.6).

TYPE LOCATION: Pershing County, Nevada; approximately 20 miles west of Imlay in a valley between the Kamma Mountains and the Antelope Range; about 1,500 feet north and 780 feet east of the southwest corner of section 1, T.33 N., R. 30 E.; USGS Sawtooth Knob, NV 7.5 minute topographic quadrangle; latitude 40 degrees 45 minutes 06 seconds N and longitude 118 degrees 33 minutes 32 seconds W; WGS84 Decimal Degrees 40.7516667 latitude, -118.558889 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually dry; moist in winter and early spring, dry from June through October; aridic soil moisture regime bordering on xeric.
Mean annual soil temperature: 12 to 13 degrees C.
Depth to the Bqk horizon: 30 to 50 cm.
Depth to secondary carbonates: 15 to 50 cm.

Particle-size control section - Clay content: Averages 20 to 30 percent.
Rock fragments: 10 to 25 percent, mainly gravel.

A horizon
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 2 through 4.

Bt and Btn horizons
Value: 5 or 6 dry, 4 or 5 moist.
Chroma: 3 or 4.
Texture: Loam, clay loam, gravelly loam or gravelly clay loam.
Structure: Prismatic in some subhorizon, usually the lower part.
Consistence: Slightly hard or hard dry, friable or firm moist.
Reaction: Moderately alkaline or strongly alkaline.
Effervescence: The matrix is typically noneffervescent; some pedons are slightly effervescent in the lower part and have few or common fine carbonate filaments.
Sodicity (SAR): 13 to 23.

Bqk horizons
Hue: 10YR or 2.5Y.
Value: 6 through 8 dry, 4 through 7 moist.
Chroma: 2 through 4.
Texture: Stratified gravelly loam to extremely gravelly coarse sandy loam.
Clay content: 7 to 15 percent.
Rock fragments: Averages 35 to 60 percent, mainly gravel.
Structure: Platy or horizon is massive.
Reaction: Moderately alkaline or strongly alkaline.
Sodicity (SAR): 24 to 46.
Effervescence: Strongly effervescent or violently effervescent.
Calcium carbonate equivalent: Less than 3 percent.
Silica cementation: Continuous brittle matrix in some subhorizons within a depth of 100 cm.

Bk horizons
Hue: 10YR or 2.5Y.
Value: 6 through 8 dry and 4 through 7 moist.
Chroma: 2 through 4.
Texture: Stratified very gravelly coarse sandy loam to extremely gravelly loamy coarse sand.
Clay content: 4 to 10 percent.
Rock fragments: 50 to 75 percent, mainly gravel.
Consistence: Slightly hard or hard dry, friable or very friable moist.
Reaction: Moderately alkaline or strongly alkaline.
Calcium carbonate equivalent: Less than 3 percent.

COMPETING SERIES: These are the Bobert, Geysen and Godecke series.

Bobert soils have Btn horizons with SAR of 50 to 100 and have less than 10 percent rock fragments. Geysen soils have mean annual soil temperature of 9 to 11 degrees C and are slightly effervescent or strongly effervescent throughout. Godecke soils have more than 30 percent clay in the particle-size control section.

GEOGRAPHIC SETTING: Pokergap soils are on erosional fan piedmont remnants. These soils formed in alluvium derived from mixed rocks including volcanic ash. Slopes are 2 to 30 percent. Elevations are 1,375 to 1,770 meters. The climate is cool, semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 200 to 250 mm; mean annual temperature is 10 to 12 degrees C, and the frost-free season is 110 to 130 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dorper and Jerval series. Dorper and Jerval soils have an aridic moisture regime.

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

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

DISTRIBUTION AND EXTENT: Northwestern Nevada. These soils are not extensive. MLRA 27.

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

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

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 15 cm (A1 and A2 horizons).
Natric horizon - The zone from about 15 to 36 cm (2Bt and 2Btn horizons).
Duric horizon - The zone from about 36 to 127 cm (2Bqk1, 2Bqk2, 3Bqk3 and 3Bqk4 horizons).
Particle-size control section - The zone from 15 to 36 cm (2Bt and 2Btn horizons).

---

National Cooperative Soil Survey
U.S.A.