LOCATION SEVENMILE NVEstablished Series
TAXONOMIC CLASS: Coarse-loamy, isotic, mesic Vitritorrandic Haploxerolls
TYPICAL PEDON: Sevenmile ashy fine sandy loam--rangeland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 3 inches; brown (10YR 5/3) ashy fine sandy loam, dark brown (10YR 3/3) moist; weak moderately thick platy structure; soft, very friable, slightly sticky and slightly plastic; few very fine roots; few fine vesicular pores; 5 percent pebbles; slightly alkaline (pH 7.8); clear smooth boundary. (2 to 6 inches thick)
A2--3 to 9 inches; brown (10YR 5/3) ashy fine sandy loam, dark brown (10YR 3/3) moist; moderate fine and medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common fine and medium roots; common very fine and fine tubular pores; 5 percent pebbles; slightly alkaline (pH 7.7); clear smooth boundary. (3 to 10 inches thick)
Bw1--9 to 17 inches; brown (10YR 5/3) ashy fine sandy loam, dark brown (10YR 3/3) moist; moderate fine and medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common fine and medium roots; common very fine and fine tubular pores; 5 percent pebbles; moderately alkaline (pH 7.9); clear smooth boundary. (5 to 14 inches thick)
Bw2--17 to 34 inches; pale brown (10YR 6/3) sandy loam, brown (10YR 4/3) moist; weak fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common fine and medium roots; common very fine and fine tubular pores; 10 percent pebbles; moderately alkaline (pH 8.1); clear smooth boundary. (6 to 25 inches thick)
C1--34 to 47 inches; pale brown (10YR 6/3) stratified sandy loam to very gravelly sandy loam, brown (10YR 4/3) moist; massive; soft, very friable, slightly sticky and slightly plastic; few fine roots; common fine interstitial pores; about 35 percent pebbles; slightly alkaline (pH 7.8); slightly effervescent; clear smooth boundary. (10 to 20 inches thick)
C2--47 to 60 inches; pale brown (10YR 6/3) stratified gravelly sandy loam to extremely gravelly loamy sand, brown (10YR 4/3) moist; massive; soft, very friable, slightly sticky and nonsticky and slightly plastic and nonplastic; few fine roots; many fine and medium interstitial pores; about 50 percent pebbles; slightly alkaline (pH 7.6).
TYPE LOCATION: Nye County, Nevada; in Ralston Valley east of the Toquima Range; about 150 feet south and 1,500 feet west of the northeast corner of section 29, T. 8 N., R. 45 E.; USGS Belmont West 7.5 minute topographic quadrangle; 38 degrees 31 minutes 16 seconds north latitude and 116 degrees 56 minutes 01 seconds west longitude, NAD 27.
RANGE IN CHARACTERISTICS:
Soil moisture - Moist in winter and spring, dry in summer and fall except for 10 to 20 days cumulative between July to October due to convection storms. Aridic soil moisture regime that borders on xeric.
Mean annual soil temperature - 52 to 57 degrees F.
Mollic epipedon thickness - 10 to 16 inches.
Depth to base of cambic horizon - 24 to 35 inches.
Sodium fluoride pH - 8.5 to 10.0.
Control section - Clay content: Averages 8 to 18 percent.
Rock fragments: Averages 10 to 35 percent, mainly pebbles. Lithology of fragments are mixed rocks.
A horizons - Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Reaction: Neutral to moderately alkaline.
Organic matter content: 1 to 3 percent.
Vitrandic intergrade properties: Volcanic glass content: 15 to 25 percent in coarse silt through fine sand fractions; Acid oxalate extractable aluminum plus one-half the acid oxalate extractable iron: 0.1 to 0.3 percent.
Bw1 horizon - Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 3 or 4, dry or moist.
Texture: Ashy fine sandy loam, ashy very fine sandy loam, or ashy loam.
Rock fragments: 5 to 15 percent.
Organic matter content: 1 or 2 percent.
Consistence: Soft or slightly hard, dry; very friable or friable, moist, slightly sticky or moderately sticky and slightly plastic or moderately plastic, wet.
Reaction: Neutral to moderately alkaline.
Vitrandic intergrade properties: Volcanic glass content: 15 to 25 percent in coarse silt through fine sand fractions; Acid oxalate extractable aluminum plus one-half the acid oxalate extractable iron: 0.1 to 0.3 percent.
Bw2 horizon - Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 3 or 4, dry or moist.
Texture: Sandy loam, very fine sandy loam, or gravelly loam.
Rock fragments: 5 to 35 percent
Consistence: Soft to moderately hard, dry; very friable or friable, moist.
Reaction: Neutral to moderately alkaline.
C horizons - Value: 6 or 7 dry, 3 through 5 moist.
Chroma: 3 or 4, dry or moist.
Texture: Stratified and dominated by fine sandy loam, sandy loam, or very fine sandy loam but includes strata of loamy coarse sand to silt loam in some pedons.
Rock fragments: Averages 10 to 35 percent, mainly pebbles; individual strata range from 0 to 65 percent.
Structure: Subangular blocky or massive.
Consistence: Soft to moderately hard, dry, nonsticky or slightly sticky and nonplastic or slightly plastic, wet.
Reaction: Slightly alkaline or moderately alkaline.
Effervescence: Noneffervescent to violently effervescent.
Calcium carbonate equivalent: 0 to 3 percent in the material less than 2 mm.
COMPETING SERIES: At present, there are no other series in this family.
GEOGRAPHIC SETTING: Sevenmile soils are on stream terraces, drainageways and inset fans. These soils formed in alluvium derived from welded tuff with minor components of limestone and quartzite. Slopes are 0 to 8 percent. Elevations range from 4,850 to 7,450 feet. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 8 to 14 inches, mean annual temperature is 47 to 55 degrees F., and the frost-free period is 100 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Mosida, Penoyer, and Rebel soils. Mosida soils are coarse-loamy, have ochric epipedons, and an irregular decrease in organic carbon. Penoyer soils are coarse-silty and have ochric epipedons. Rebel soils are coarse-loamy and have ochric epipedons.
DRAINAGE AND PERMEABILITY: Well drained; very low or low surface runoff; moderately rapid permeability. These soils are susceptible to rare flooding for very brief periods year-round.
USE AND VEGETATION: Sevenmile soils are used for livestock grazing and wildlife habitat. The vegetation is mainly Wyoming big sagebrush, rabbitbrush, Indian ricegrass, thickspike wheatgrass, and basin wildrye.
DISTRIBUTION AND EXTENT: Central Nevada. These soils are not extensive. MLRAs 28B, 28A and 29.
MLRA OFFICE RESPONSIBLE: Reno, Nevada.
SERIES ESTABLISHED: Nye County (Northwest Part), Nevada, 1994.
REMARKS: This revision updates the taxonomic classification from Coarse-loamy, mixed, superactive, mesic Aridic Haploxerolls.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 17 inches (A1, A2, and Bw1 horizons).
Vitrandic intergrade feature - The zone from the soil surface to 17 inches (A1, A2, and Bw1 horizons).
Cambic horizon - The zone from 17 to 34 inches (Bw2 horizon).
Particle-size control section - The zone from 10 to 40 inches (Bw2 horizon and parts of the Bw1 and C1 horizons).
ADDITIONAL DATA: The typical pedon at the series type location was sampled for full characterization by the Soil Survey Laboratory (SSL), Lincoln, NE, as soil survey sample number S92nv-023-006 (pedon # 92P0575).