LOCATION IZO                     NV

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

IZO SERIES

The Izo series consists of very deep, excessively drained soils that formed in alluvium derived from mixed rocks. Izo soils are on drainageways, inset fans, and fan skirts. Slopes are 0 to 15 percent. The mean annual precipitation is about 150 mm and the mean annual temperature is about 12 degrees C.

TAXONOMIC CLASS: Sandy-skeletal, mixed, mesic Typic Torriorthents

TYPICAL PEDON: Izo very gravelly sand--rangeland. (Colors are for dry soil unless otherwise noted.)

A--0 to 3 cm; pale brown (10YR 6/3) very gravelly sand, brown (10YR 4/3) moist; single grain; loose, nonsticky and nonplastic; common very fine roots; many very fine interstitial pores; 35 percent gravel; slightly effervescent; moderately alkaline (pH 8.2); abrupt smooth boundary. (3 to 13 cm thick)

C1--3 to 20 cm; pale brown (10YR 6/3) very gravelly sand, brown (10YR 4/3) moist; single grain; loose, nonsticky and nonplastic; common very fine and fine roots; many very fine interstitial pores; 35 percent gravel and 2 percent cobbles; strongly effervescent; moderately alkaline (pH 8.4); abrupt wavy boundary.

C2--20 to 56 cm; pale brown (10YR 6/3) stratified very gravelly loamy coarse sand and very gravelly coarse sand, brown (10YR 4/3) moist; massive; soft, very friable, nonsticky and nonplastic; common very fine, fine and few medium roots; many very fine, fine and medium interstitial pores; 45 percent gravel and 5 percent cobbles; strongly effervescent; strongly alkaline (pH 8.6); abrupt wavy boundary.

C3--56 to 89 cm; pale brown (10YR 6/3) stratified very gravelly loamy coarse sand and extremely gravelly coarse sand, brown (10YR 4/3) moist; massive; soft, very friable, nonsticky and nonplastic; few very fine and fine roots; many very fine, fine and medium interstitial pores; 50 percent gravel and 5 percent cobbles; strongly effervescent; strongly alkaline (pH 8.8); abrupt wavy boundary.

C4--89 to 152 cm; pale brown (10YR 6/3) very gravelly coarse sand, brown (10YR 4/3) moist; massive; soft, very friable, nonsticky and nonplastic; few very fine and fine roots; many very fine, fine and medium interstitial pores; 45 percent gravel; strongly effervescent; strongly alkaline (pH 8.8). (Combined thickness of the C horizons is more than 152 cm)

TYPE LOCATION: Esmeralda County, Nevada; approximately 1,200 feet south and 1,750 feet east of the northwest corner of section 31, T. 2 N., R. 42 E.; USGS Klondike 7.5 minute topographic quadrangle; latitude 37 degrees 59 minutes 19.3 seconds N and longitude 117 degrees 18 minutes 29.8 seconds W; UTM zone 11N 472929E, 4204605N, WGS84 Decimal Degrees 37.9888889 latitude, -117.308472 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually dry, moist in some part for short periods in 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 15 degrees C.
Reaction: Moderately alkaline or strongly alkaline, commonly increasing with depth.
Effervescence: Slightly effervescent through strongly effervescent. Individual thin strata are noneffervescent in some pedons.

Particle-size control section - Clay content: 0 to 5 percent.
Rock fragments: Averages 50 to 75 percent, mainly gravel larger than 13 mm in diameter. Lithology of fragments is mixed.

A horizon
Value: 6 or 7 dry, 4 or 5 moist.
Chroma: 3 or 4, dry or moist.
Other features: This horizon commonly is structureless or has finely stratified rock structure and does not qualify as an ochric epipedon.

C horizons
Hue: 10YR or 2.5Y.
Value: 6 or 7 dry, 4 or 5 moist.
Chroma: 2 through 4, dry or moist.
Structure: Massive or single grain.
Consistence: Loose or soft, loose or very friable.
Texture: Stratified coarse sand, sand, loamy sand, and loamy coarse sand.
Rock fragments: 50 to 75 percent, predominantly gravel. Individual strata range from 15 to 85 percent rock fragments.
Identifiable secondary carbonates: Some pedons have up to 50 percent of the undersides of rock fragments in any subhorizon covered with thin lime coats.

COMPETING SERIES: These are the Bluewing, Gynelle, Inmo, Ioka, Itme, Izamatch, Leo, Nepalto, Wardenot, and Willwood series.

Bluewing soils have a weak Bk horizon and are not moist for 10 to 20 days during the summer. Gynelle soils have strata of sandy loam within the particle-size control section. Inmo and Itme soils are dominated by fine gravel (less than 10 mm in diameter). Ioka soils have mean annual soil temperature of 8 to 9 degrees C. Gynelle, Leo, and Wardenot soils have sandy loam horizons. Izamatch soils do not have thin stratification, have lime accumulation at 38 to 50 cm, and contain 30 to 40 percent calcium carbonate equivalent in the lower part of the profile. Nepalto soils are not stratified, have texture of very fine sandy loam in the upper 20 to 36 cm of the soil and have hue of 2.5YR or 5YR. Willwood soils have mean annual soil temperature of 9 to 10 degrees C, have less than 50 percent coarse and very coarse sands, and are not moist for 10 to 20 days cumulative between July and October.

GEOGRAPHIC SETTING: Izo soils are on drainageways, inset fans, and fan skirts. They formed in recent alluvium derived from mixed rocks. Slopes are 0 to 15 percent. Elevations range from 1,200 to 2,220 meters. The mean annual precipitation is 100 to 200 mm, the mean annual temperature is 11 to 14 degrees C, and the frost-free period is 100 to 150 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Stumble, Terlco, and Unsel soils and the competing Wardenot soil. Stumble soils are sandy and nongravelly. Terlco soils are fine-loamy, have natric horizons, and occur on fan remnants. Unsel soils are fine-loamy, have argillic horizons and weakly silica-cemented layers, and occur on fan remnants.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Excessively drained; very low or low surface runoff; high saturated hydraulic conductivity. Flooding frequency ranges from nonflooded to occasionally flooded for very brief periods.

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

DISTRIBUTION AND EXTENT: Western and central Nevada. These soils are extensive with about 158,000 acres of the series mapped to date. MLRAs 27, 29, and 28B.

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

SERIES ESTABLISHED: Esmeralda County, Nevada, 1984.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the surface to 18 cm (A and part of C1 horizons).
Particle-size control section - The zone from 25 to 100 cm (C3 horizon and part of the C2 and C4 horizons).

---

National Cooperative Soil Survey
U.S.A.