LOCATION IZO NVEstablished Series
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; 37 degrees 59 minutes 19.3 seconds north latitude and 117 degrees 18 minutes 29.8 seconds west longitude, NAD83; UTM zone 11N 472929E, 4204605N, NAD83.
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 torric moisture regime.
Mean annual soil temperature - 12 to 15 degrees C.
Particle-size control section - Rock fragments: Averages 50 to 75 percent, mainly pebbles larger than 13 millimeters in diameter. Lithology of fragments are mixed.
Reaction - Moderately alkaline or strongly alkaline, commonly increasing with depth.
Effervescence- Slightly effervescent or strongly effervescent. Individual thin strata are noneffervescent in some pedons.
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 (less than 2 mm fraction): Stratified coarse sand, sand, loamy sand, and loamy coarse sand.
Rock fragments: 50 to 75 percent, predominantly pebbles. 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 (T), 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 pebbles (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 1,980 meters. The mean annual precipitation is 100 to 200 mm, the mean annual temperature is 51 to 57 degrees F., 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 PERMEABILITY: Excessively drained; very low or low surface runoff; rapid permeability (high or very high saturated hydraulic conductivity). Flooding frequency ranges from nonflooded to occasionally flooded for very brief periods.
USE AND VEGETATION: Izo soils are used for rangeland 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 OFFICE RESPONSIBLE: Reno, Nevada.
SERIES ESTABLISHED: Esmeralda County, Nevada, 1984.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Particle-size control section - The zone from 25 to 100 cm (C3 horizon and part of the C2 and C4 horizons).