LOCATION DORPER                  NV

Established Series
Rev. MJZ/RLB/JVC/JBF
05/2016

DORPER SERIES

The Dorper series consists of very deep, well drained soils that formed in alluvium derived from mixed rock sources with a component of loess and volcanic ash. Dorper soils are on fan remnants. Slopes are 2 to 30 percent. The mean annual precipitation is about 125 mm and the mean annual temperature is about 12 degrees C.

TAXONOMIC CLASS: Fine, smectitic, mesic Durinodic Natrargids

TYPICAL PEDON: Dorper extremely gravelly very fine sandy loam--rangeland. (Colors are for dry soil unless otherwise noted.) The soil surface is partially covered with 70 percent gravel, 5 percent cobbles, and 1 percent stones.

A1--0 to 5 cm; pale brown (10YR 6/3) extremely gravelly very fine sandy loam, brown (10YR 4/3) moist; weak thin platy structure; soft, very friable, slightly sticky and slightly plastic; few very fine roots; common fine vesicular pores; 65 percent gravel; slightly effervescent; moderately alkaline (pH 8.2); clear smooth boundary. (3 to 10 cm thick)

A2--5 to 13 cm; pale brown (10YR 6/3) gravelly very fine sandy loam, brown (10YR 4/3) moist; weak thin platy structure; soft, very friable, slightly sticky and slightly plastic; few very fine roots; many fine tubular pores; 15 percent gravel; slightly effervescent; moderately alkaline (pH 8.4); clear wavy boundary. (0 to 18 cm thick)

E--13 to 18 cm; light gray (10YR 7/2) ashy silt loam, pale brown (10YR 6/3) moist; strong thin platy structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and fine roots; many very fine and few fine tubular pores; 5 percent gravel; violently effervescent; strongly alkaline (pH 9.0); abrupt smooth boundary. (0 to 8 cm thick)

2Btnk1--18 to 25 cm; pale brown (10YR 6/3) clay, brown (7.5YR 4/4) moist; moderate fine prismatic structure; hard, friable, very sticky and very plastic; many very fine and common fine roots; many very fine and common fine tubular pores; 5 percent gravel; many faint clay films on faces of peds and lining pores; secondary carbonates segregated in few fine filaments, masses, and as coats on bottoms of fragments; slightly effervescent; strongly alkaline (pH 8.8); gradual smooth boundary. (8 to 33 cm thick)

2Btnk2--25 to 43 cm; pinkish gray (7.5YR 6/2) gravelly clay loam, brown (7.5YR 5/4) moist; moderate fine prismatic structure; hard, firm, very sticky and very plastic; many very fine and common fine roots; many very fine tubular pores; 15 percent gravel; many faint clay films on faces of peds and lining pores; secondary carbonates segregated in many fine seams and as coats on bottoms of fragments; strongly effervescent; strongly alkaline (pH 8.8); clear smooth boundary. (5 to 18 cm thick)

3Bqk--43 to 66 cm; very pale brown (10YR 7/3) very gravelly sandy loam, yellowish brown (10YR 5/4) moist; massive; soft, very friable, slightly sticky and slightly plastic; common very fine and few fine roots; few very fine tubular pores; 35 percent gravel and 5 percent cobbles; 30 percent moderately cemented durinodes and 30 percent weak discontinuous silica cementation; secondary carbonates segregated as coats on gravel; violently effervescent; moderately alkaline (pH 8.4); clear wavy boundary. (18 to 122 cm thick)

3Bk--66 to 152 cm; light gray (10YR 7/2) extremely gravelly sandy loam, brown (10YR 5/3) moist; massive; soft, very friable, slightly sticky and slightly plastic; few very fine roots; few very fine tubular pores; 65 percent gravel and 5 percent cobbles; secondary carbonates segregated as coats on bottoms of gravel; violently effervescent, moderately alkaline (pH 8.0).

TYPE LOCATION: Pershing County, Nevada; about 16 miles west-northwest of Imlay; in nonsectionized township T. 33 N., R. 32 E.; approximately 3,500 feet east and 1,600 feet north of the southeast corner of section 25, T. 33 N., R. 31 E.; USGS Majuba Mountain 7.5 minute topographic quadrangle; latitude 40 degrees 41 minutes 39 seconds N and longitude 118 degrees 24 minutes 56 seconds W; WGS84 Decimal Degrees 40.6941667 latitude, -118.415556 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually dry, moist for short periods in winter and early spring, dry late May through November; typic aridic soil moisture regime.
Mean annual soil temperature: 12 to 14 degrees C.
Depth to the base of the natric horizon: 25 to 50 cm.
Depth to identifiable secondary carbonates: 10 to 46 cm.
Depth to 3Bqk horizon: 25 to 50 cm.
Reaction: Moderately alkaline or strongly alkaline.
Other features - Some pedons have significant volcanic glass content in the A and E horizons.

Particle-size control section - Clay content: 35 to 45 percent.
Rock fragments: 5 to 25 percent.

A horizons
Value: 6 or 7 dry, 4 or 5 moist.
Chroma: 2 through 4, dry or moist.
Consistence: Soft or slightly hard dry, very friable or friable moist.
Effervescence: Varies from noneffervescent to violently effervescent as a result of calcareous eolian surface deposits.

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 gravelly clay loam.
Rock fragments: 5 to 25 percent.
Salinity (EC): 2 to 8 mmhos/cm.
Sodium adsorption ratio: 13 to 45.
Identifiable secondary carbonates: The 2Btnk1 horizon has none to few filaments or masses and is noneffervescent or slightly effervescent; the 2Btnk2 horizon has common or many filaments or masses and is slightly effervescent or strongly effervescent.
Calcium carbonate equivalent: 0 to 10 percent.
Gypsum content: 0 to 1 percent as few fine filaments in the 2Btnk2 horizon.

3Bqk horizon
Value: 5 through 7 dry, 3 through 5 moist.
Chroma: 2 through 4, dry or moist.
Texture: Very gravelly coarse sandy loam or extremely gravelly sandy loam.
Clay content: 8 to 15 percent.
Rock fragments: 40 to 75 percent.
Silica cementation: 20 to 40 percent weak through strongly cemented durinodes in a friable matrix or has weak or strong discontinuous silica cementation with common thin discontinuous silica laminae; continuous weakly silica cemented strata are common below a depth of 100 cm in some pedons.
Calcium carbonate equivalent: 1 to 10 percent.
Gypsum content: 0 to 5 percent.
Other features: In some pedons, loamy coarse sand is common at some depth below 100 cm.

COMPETING SERIES: These are the Beeox and Oxcorel series.

Beeox soils have a Bq horizon above the natric horizon and have mean annual soil temperature of 8 to 11 degrees C. Oxcorel soils have mean annual soil temperature of 8 to 11 degrees C. and have the base of the natric horizon at depths of 50 to 100 cm.

GEOGRAPHIC SETTING: Dorper soils are on fan remnants. These soils formed in alluvium derived from mixed rock sources with a component of loess and volcanic ash. Slopes are 2 to 30 percent. Elevations range from 1,160 to 1,770 meters. The climate is arid with cool, moist winters and warm, dry summers. The mean annual precipitation is 100 to 200 mm, the mean annual temperature is 10 to 12 degrees C., and the frost-free period is 110 to 135 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bluewing, Genegraf, and Jerval soils. Bluewing soils do not have diagnostic subsurface horizons. Genegraf and Jerval soils are fine-loamy.

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

USE AND VEGETATION: Dorper soils are used for rangeland and wildlife habitat. The present vegetation is mainly shadscale, bud sagebrush, cheatgrass, bottlebrush squirreltail, and bluegrass. Phases with a extremely gravelly surface also have Bailey's greasewood.

DISTRIBUTION AND EXTENT: Western Nevada. These soils are extensive with about 126,000 acres of the series mapped to date. MLRA 27.

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

SERIES ESTABLISHED: Pershing County, Nevada (West Part), 1988. The name is coined.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 18 cm (A1, A2, and E horizons).
Natric horizon - The zone from 18 to 43 cm (2Btnk1 and 2Btnk2 horizons).
Identifiable secondary carbonates - The zone from 18 to 152 cm (2Btnk1, 2Btnk2, 3Bqk, and 3Bk horizons).
Durinodes - The zone from 18 to 66 cm (3Bqk horizon).
Particle-size control section - The zone from 18 to 43 cm (2Btnk1 and 2Btnk2 horizons).

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National Cooperative Soil Survey
U.S.A.