LOCATION PONYSPRING              NV

Established Series
Rev. CWL/TM/JBF
02/2012

PONYSPRING SERIES

The Ponyspring series consists of very deep, well drained soils that formed in alluvium derived from welded tuff. The Ponyspring soils are on fan remnants. Slopes range from 0 to 15 percent. The mean annual precipitation is about 330 mm and the mean annual temperature is about 8 degrees C.

TAXONOMIC CLASS: Ashy, glassy, mesic Vitritorrandic Argixerolls

TYPICAL PEDON: Ponyspring gravelly ashy loamy coarse sand--rangeland. (Colors are for dry soil unless otherwise noted.) The soil surface is covered with approximately 40 percent gravel; lithology of fragments is welded tuff.

A1--0 to 5 cm; brown (10YR 5/3) gravelly ashy loamy coarse sand, dark brown (10YR 3/3) moist; weak medium granular structure; soft, very friable, slightly sticky and nonplastic; few very fine and fine roots; few very fine and fine irregular and tubular pores; 25 percent gravel and 5 percent cobbles; neutral (pH 7.0); clear smooth boundary. (5 to 15 cm thick)

A2--5 to 15 cm; dark grayish brown (10YR 4/2) gravelly ashy sandy loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; few very fine, common fine and few medium roots; few very fine and fine irregular and tubular pores; 15 percent gravel and 5 percent cobbles; neutral (pH 7.2); clear smooth boundary. (0 to 18 cm thick)

Btk1--15 to 30 cm; brown (10YR 5/3) cobbly ashy sandy clay loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; few very fine, common fine and medium roots; common fine and medium irregular and tubular pores; common distinct clay films on faces of peds; 15 percent gravel and 15 percent cobbles; few (2 percent) distinct secondary calcium carbonate concretions on bottom of rock fragments; neutral (pH 7.0); clear smooth boundary. (8 to 30 cm thick)

Btk2--30 to 51 cm; yellowish brown (10YR 5/4) gravelly ashy sandy clay loam, dark yellowish brown (10YR 3/4) moist; strong coarse subangular blocky structure; very hard, very firm, moderately sticky and moderately plastic; few very fine, common fine and medium roots; common fine and medium irregular and tubular pores; many distinct clay films on faces of peds and lining pores; 15 percent gravel; common (5 percent) distinct secondary calcium carbonate concretions around rock fragments; neutral (pH 7.2); clear smooth boundary.

Btk3--51 to 76 cm; yellowish brown (10YR 5/4) gravelly ashy sandy loam, dark yellowish brown (10YR 3/4) moist; strong coarse subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; few very fine, common fine and few medium roots; common very fine and fine irregular and tubular pores; common faint clay films on faces of peds; 20 percent gravel; common (5 percent) distinct secondary calcium carbonate concretions around rock fragments; slightly alkaline (pH 7.5); clear smooth boundary. (Combined thickness of the Btk2 and Btk3 horizons is 40 to 60 cm)

Btqk1--76 to 117 cm; yellowish brown (10YR 5/4) ashy clay loam, dark yellowish brown (10YR 4/4) moist; strong coarse subangular blocky structure parting to moderate medium subangular blocky; hard, firm, moderately sticky and moderately plastic; few very fine and fine roots; few very fine irregular pores; common distinct clay films on faces of peds and coating sand grains; 10 percent gravel and 1 percent cobbles; common (10 percent) distinct secondary calcium carbonate and secondary silica concretions around rock fragments and common (10 percent) secondary calcium carbonate masses and fine threads; slightly effervescent; slightly alkaline (pH 7.5); clear smooth boundary. (25 to 50 cm thick)

Btqk2--117 to 152 cm; light yellowish brown (10YR 6/4) gravelly ashy coarse sandy loam, dark yellowish brown (10YR 4/4) moist; massive; hard, firm, moderately sticky and moderately plastic; few very fine roots; few very fine irregular pores; common distinct clay films on faces of peds and bridging sand grains; 15 percent gravel and 2 percent cobbles; common (10 percent) distinct secondary calcium carbonate and secondary silica concretions around rock fragments and secondary calcium carbonate disseminated throughout; strongly effervescent; moderately alkaline (pH 8.1).

TYPE LOCATION: Lincoln County, Nevada; approximately 3 miles south of Pony Springs, 0.5 miles west of State Highway 93; about 1,200 feet north and 800 feet east of the southwest corner section 20, T. 5 N., R. 66 E.; USGS Pony Springs 7.5 minute topographic quadrangle; latitude 38 degrees 16 minutes 29 seconds N and longitude 114 degrees 36 minutes 8 seconds W; NAD 83.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually dry, moist for short periods in winter and early spring and intermittently moist for 10 to 20 days cumulative from July through September due to convection storms; aridic soil moisture regime bordering on xeric.
Soil temperature: 8 to 11 degrees C.
Thickness of the mollic epipedon: 25 to 36 cm and may include the upper part of the argillic horizon.
Depth to argillic horizon: 8 to 18 cm.
Depth to identifiable secondary calcium carbonate: 15 to 36 cm.
Mineralogy: 40 to 60 percent volcanic glass in the 0.2 to 2.0 mm fraction.

Particle-size control section - Clay content: 18 to 27 percent.
Rock fragments: 15 to 35 percent, mainly gravel.

A horizons
Value: 4 or 5 dry.
Chroma: 2 or 3, dry or moist.
Structure: Weak or moderate granular or subangular blocky.

Btk horizons
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 through 4, dry or moist.
Texture: Gravelly ashy sandy loam, gravelly ashy clay loam, gravelly ashy sandy clay loam, or cobbly ashy sandy clay loam.
Clay content: 18 to 27 percent.
Rock fragments: 15 to 35 percent.
Structure: Moderate to strong, medium to coarse subangular blocky.
Secondary calcium carbonate: Faint to distinct concretions on bottom or around rock fragments.
Reaction: Neutral or slightly alkaline.

Btqk horizons
Hue: 10YR or 7.5YR.
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 3 or 4, dry or moist.
Texture: Gravelly ashy coarse sandy loam, ashy sandy clay loam, and ashy clay loam.
Clay content: 18 to 35 percent.
Rock fragments: 10 to 35 percent.
Structure: Massive or medium to coarse subangular blocky.
Reaction: Neutral to moderately alkaline.
Effervescence: Slightly effervescent or strongly effervescent.
Calcium carbonate equivalent: 1 to 5 percent in the material less than 2 mm.

COMPETING SERIES: These are the Ashone, Bidwell, Coppersmith and Simpson series.

The Ashone soils are moderately deep to paralithic material, do not have secondary calcium carbonate in the profile and are not intermittently moist for 10 to 20 days cumulative from July to September due to convection storms. Bidwell soils have 0 to 10 percent rock fragments in the particle-size control section and are not intermittently moist for 10 to 20 days cumulative from July to September due to convection storms. Coppersmith soils contain 20 to 70 percent durinodes and are not intermittently moist for 10 to 20 days cumulative from July to September due to convection storms. Simpson soils have a mollic epipedon that is 50 to 69 cm thick and have 35 to 50 percent clay in the particle-size control section.

GEOGRAPHIC SETTING: Ponyspring soils are on fan remnants. These soils formed in alluvium derived from welded tuff. Slopes range from 0 to 15 percent. Elevations range from 1,650 to 2,290 meters. The mean annual temperature is 7 to 10 degrees C, mean annual precipitation is 300 to 360 mm and the frost-free period is 90 to 110 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cath, Nevu, Okayview and Zoda series. Cath soils have a mean annual soil temperature of 12 to 14 degrees and contain a horizon with a firm and brittle matrix. Nevu soils are moderately deep to a duripan. Okayview soils are shallow to a paralithic contact. Zoda soils are moderately deep to a duripan.

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

USE AND VEGETATION: Livestock grazing and wildlife habitat. The potential native vegetation includes bluebunch wheatgrass, Thurbers needlegrass, muttongrass, basin wildrye, mountain big sagebrush and antelope bitterbrush. This pedon is correlated to Ecological Site R028AY092NV, Loamy 12-14 P.Z.

DISTRIBUTION AND EXTENT: South central Nevada. Ponyspring soils are not extensive. MLRA 28A and 29.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona.

SERIES ESTABLISHED: Lincoln County, Nevada, North Part; 2004. The name is from a spring in the area.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 30 cm (A1, A2 and Btk1 horizons).
Argillic horizon - The zone from 15 to 152 cm (Btk1, Btk2, Btk3, Btqk1 and Btqk2 horizons).
Particle-size control section - The zone from 15 to 65 cm (Btk1, Btk2 and the upper part of the Btk3 horizons).

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National Cooperative Soil Survey
U.S.A.