LOCATION DOWNEYVILLE             NV

Established Series
Rev. JBF-WED-JVC
05/2016

DOWNEYVILLE SERIES

The Downeyville series consists of very shallow and shallow, well drained soils that formed in residuum and colluvium derived from volcanic rocks. Downeyville soils are on hills, mountains, rock pediments, plateaus, and mesas. Slopes are 4 to 75 percent. The mean annual precipitation is about 150 mm and the mean annual temperature is about 11 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Lithic Haplargids

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

A--0 to 5 cm; light brownish gray (10YR 6/2) very gravelly fine sandy loam, dark grayish brown (10YR 4/2) moist; weak fine and medium subangular blocky structure; soft, very friable, slightly sticky and nonplastic; few very fine roots; common very fine interstitial pores; 45 percent gravel and 10 percent cobbles; moderately alkaline (pH 8.0); clear smooth boundary. (3 to 10 cm thick)

ABk--5 to 10 cm; pale brown (10YR 6/3) gravelly fine sandy loam, brown (10YR 4/3) moist; weak fine platy and weak fine subangular blocky structure; soft, very friable, slightly sticky and nonplastic; common very fine, fine, and medium roots; common very fine and fine interstitial and tubular pores; 20 percent gravel; secondary carbonates segregated as few fine coats on bottoms of rock fragments; moderately alkaline (pH 8.0); clear smooth boundary. (0 to 10 cm thick)

Btk1--10 to 15 cm; pale brown (10YR 6/3) gravelly loam, brown (10YR 4/3) moist; moderate thin platy and moderate fine subangular blocky structure; soft, friable, slightly sticky and slightly plastic; common very fine, fine and medium roots; common very fine and fine interstitial and tubular pores; few faint clay films on faces of peds and lining pores; 30 percent gravel; secondary carbonates segregated as common medium coats on bottoms of rock fragments; moderately alkaline (pH 8.2); abrupt smooth boundary. (0 to 20 cm thick)

Btk2--15 to 23 cm; very pale brown (10YR 7/4) very gravelly loam, dark yellowish brown (10YR 4/4) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, moderately sticky and slightly plastic; common very fine and fine roots; common very fine and fine interstitial and tubular pores; few faint clay films on faces of peds and lining pores; 30 percent gravel and 15 percent cobbles; secondary carbonates segregated as many medium and coarse coats on bottoms of rock fragments; slightly effervescent; moderately alkaline (pH 8.4); abrupt wavy boundary. (5 to 18 cm thick)

R--23 cm; fractured hard tuff; discontinuous lime and silica cementation in fractures; weathered in upper 5 cm.

TYPE LOCATION: Esmeralda County, Nevada; south of Lida Valley and about 2 miles southwest of Gold Point; approximately 2,400 feet west and 2,100 feet south of the northeast corner of section 13, T. 7 S., R. 41 E.; USGS Gold Point SW 7.5 minute topographic quadrangle; latitude 37 degrees 19 minutes 50 seconds N and longitude 117 degrees 23 minutes 01 seconds W; WGS84 Decimal Degrees 37.3305556 latitude, -117.383611 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually moist in some part for short periods during winter 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 14 degrees C.
Ochric epipedon thickness: 3 to 20 cm.
Depth to bedrock: 10 to 36 cm to a lithic contact.
Effervescence: Noneffervescent through strongly effervescent.

Particle-size control section - Clay content: Averages 14 to 25 percent.
Rock fragments: 35 to 60 percent, mainly gravel. Lithology of fragments is volcanic rocks such as tuff, basalt, rhyolite, or andesite.

A and ABk horizons
Hue: 7.5YR or 10YR.
Value: 6 or 7 dry, 3 through 5 moist.
Chroma: 2 or 3, dry or moist.
Reaction: Neutral to moderately alkaline.
Calcium carbonate equivalent: 0 to 5 percent.
Identifiable secondary carbonates: Occurs as none to few coats on the bottoms of rock fragments.

Bt and Btk horizons
Value: 5 through 7 dry, 3 through 5 moist.
Chroma: 2 through 4, dry or moist.
Texture: Very gravelly loam or very gravelly fine sandy loam; some pedons may have subhorizons of very gravelly silt loam.
Clay content: 18 to 27 percent.
Rock fragments: 30 to 50 percent gravel, 5 to 20 percent cobbles and stones.
Structure: Platy or subangular blocky.
Consistence: Soft to hard dry, very friable or friable moist, slightly sticky or moderately sticky and nonplastic or slightly plastic wet.
Reaction: Moderately alkaline or strongly alkaline.
Calcium carbonate equivalent: 0 to 10 percent.
Identifiable secondary carbonates: Occurs as few to many coats or pendants on the bottoms of rock fragments.
Effervescence: Slightly effervescent to violently effervescent in lower part.
Other features: The upper part of the argillic horizon may not contain identifiable secondary carbonates or may not be effervescent in some pedons; Some pedons have few coats of secondary silica.

COMPETING SERIES: These are the Etinarg, Hoot, Mirkwood, Theon, Tognoni, Valleycity, Vium, and Waucoba series.

Etinarg soils have 35 to 65 percent fine granite gravel in the particle-size control section and do not have identifiable secondary carbonates. Hoot soils are noncalcareous throughout the profile and have a neutral reaction class in the argillic horizon. Mirkwood soils have 25 to 35 percent clay in the argillic horizon. Theon soils have 25 to 35 percent clay in the particle-size control section and are noncalcareous. Tognoni soils have more than 35 percent clay in the argillic horizon. Valleycity soils contain mainly stones and cobbles in the particle-size control section which are fragments of calcareous sandstone. Vium soils are dry between July and October, have 10 to 18 percent clay in the argillic horizon, and contain rock fragments of granite. Waucoba soils are 36 to 50 cm deep to bedrock.

GEOGRAPHIC SETTING: Downeyville soils are on hills, mountains, rock pediments, plateaus, and mesas. They formed in residuum and colluvium derived from volcanic rocks. Slopes are 4 to 75 percent. Elevations range from 1,032 to 2,380 meters. The mean annual precipitation is 100 to 200 mm, the mean annual temperature is 9 to 13 degrees C, and the frost-free period is 110 to 150 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Blacktop, Pintwater, and Stewval soils. Blacktop and Pintwater soils are loamy-skeletal, have ochric epipedons, and do not have argillic horizons. Stewval soils are loamy-skeletal and have an aridic moisture regime that borders on xeric.

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

USE AND VEGETATION: Downeyville soils are used for livestock grazing and wildlife habitat. The present vegetation is mainly bud sagebrush, shadscale, Indian ricegrass, and galleta.

DISTRIBUTION AND EXTENT: Western Nevada. These soils are extensive with about 300,000 acres of the series mapped to date. The series concept and main acreage is in MLRA 29, while other acreage occurs in MLRAs 26 and 27.

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

SERIES ESTABLISHED: Esmeralda County Area, Nevada, 1984.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 10 cm (A and ABk horizons).
Argillic horizon - The zone from 10 to 23 cm (Btk1 and Btk2 horizons).
Identifiable secondary carbonates - The zone from 5 to 23 cm (ABk, Btk1, and Btk2 horizons).
Lithic contact - The boundary at 23 cm to underlying hard bedrock (R layer).
Particle-size control section - The zone from the soil surface to 23 cm (A, ABk, Btk1, and Btk2 horizons).

ADDITIONAL DATA: The series type location has full characterization by the Soil Survey Laboratory (SSL), Lincoln, NE, as soil survey sample number S83NV-009-003 (pedon # 83P0614).

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National Cooperative Soil Survey
U.S.A.