LOCATION OEST NV+CAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Aridic Argixerolls
TYPICAL PEDON: Oest gravelly sandy loam--rangeland. (Colors are for dry soil unless otherwise noted).
A--0 to 14 inches; grayish brown (10YR 5/2) gravelly sandy loam, very dark grayish brown (10YR 3/2) moist; moderate fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; 15 percent gravel, 5 percent cobbles, and .01 to .1 percent boulders and stones; slightly acid (pH 6.3); clear smooth boundary. (10 to 18 inches thick)
Bt1--14 to 28 inches; light brown (7.5YR 6/4) very gravelly sandy loam, brown (7.5YR 4/4) moist; weak coarse prismatic structure; slightly hard, friable, slightly sticky and slightly plastic; common distinct clay films on faces of peds and rock fragments; 30 percent gravel, 10 percent cobbles, and 5 percent stones; slightly acid (pH 6.5); gradual wavy boundary. (10 to 20 inches thick)
Bt2--28 to 40 inches; light brown (7.5YR 6/4) very gravelly sandy loam, brown (7.5YR 4/4) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few distinct clay films on rock fragments; 40 percent gravel, 10 percent cobbles, and 5 percent stones; slightly acid (pH 6.5); gradual wavy boundary. (10 to 20 inches thick)
C--40 to 50 inches; pale brown (10YR 6/3) very gravelly loamy sand, brown (7.5YR 4/4) moist; single grain; loose; 50 percent gravel, 10 percent cobbles, and 1 to 5 percent stones; slightly acid (pH 6.5).
TYPE LOCATION: Washoe County, Nevada; on the Toiyabe National Forest about 2 miles southwest of Verdi between Interstate 80 and the Nevada-California state line; approximately 600 feet south and 1,800 feet west of the east quarter corner of section 19, T. 19 N., R. 18 E.; USGS Mount Rose NW 7.5 minute topographic quadrangle; 39 degrees 29 minutes 48 seconds north latitude and 119 degrees 59 minutes 54 seconds west longitude, NAD27.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually moist in winter and spring, dry in summer and fall; Aridic moisture regime that borders on xeric.
Mean annual soil temperature - 50 to 52 degrees F.
Mollic epipedon thickness - 10 to 18 inches.
Depth to base of argillic horizon - 30 to 54 inches.
Particle-size control section - Clay content: 18 to 25 percent; Rock fragments: 40 to 60 percent, mainly gravel. Lithology of fragments are mixed igneous rocks such as andesite, tuff, and granodiorite.
A horizon - Hue: 10YR or 7.5YR.
Value: 4 or 5 dry.
Chroma: 2 or 3, dry or moist.
Structure: Granular or subangular blocky structure.
Other features: 0 to 15 percent stones and boulders on the soil surface.
Bt horizons - Hue: 10YR through 5YR.
Value: 4 through 6 moist.
Chroma: 3 or 4, dry or moist.
Texture: Very gravelly sandy loam, very gravelly sandy clay loam, or very bouldery sandy clay loam.
Clay content: 18 to 25 percent.
Rock fragments: 40 to 60 percent.
Structure: Weak or coarse prismatic or angular blocky.
Reaction: Slightly acid or neutral.
Other features: Some pedons have hue of 5YR in these horizons.
C horizon (when present) - Hue: 10YR or 7.5YR.
Value: 5 through 7 dry, 4 or 5 moist.
Chroma: 2 through 4, dry or moist.
Texture: Very gravelly loamy sand, extremely gravelly sand, or very bouldery sand.
Rock fragments: 50 to 80 percent.
Reaction: Slightly acid or neutral.
Other features: Thin strata of gravelly sandy loam are in some pedons.
COMPETING SERIES: These are the Ashue, Badena, Badenaugh, Eaglerock, Gitabyte (T), Grinrod, Ister, Lemm, Leviathan, Nosrac, Searles, Searvar, Shawmount, Shree, Shroe, Trid, and Tristan series.
Ashue soils have depth to base of the argillic horizon that is less than 30 inches. Badena soils are dominated by cobbles and have 60 to 85 percent rock fragments in the particle-size control section. Badenaugh, Leviathan, Nosrac, Shree, and Shroe soils have more than 25 percent clay in the argillic horizon. Eaglerock, Searvar, and Trid soils are moderately deep to paralithic contacts. Gitabyte, Grinrod, Ister, and Searles soils are moderately deep to lithic contacts. Lemm soils average 10 to 18 percent clay in the particle-size control section. Shawmount soils have a horizon with lamellae below the argillic horizon. Tristan soils are deep to lithic contacts.
GEOGRAPHIC SETTING: Oest soils are on stream terraces. They formed in alluvium derived from mixed igneous rocks that are mainly andesite, tuff, and granodiorite. Slopes are 0 to 50 percent. Elevations range from 4,500 to 5,500 feet. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 8 to 14 inches. The mean annual temperature is 47 to 51 degrees F., the mean January temperature is 30 to 32 degrees F., and the mean July temperature is 68 to 70 degrees F. The frost-free period is 100 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Orr and Springmeyer soils. Orr and Springmeyer soils have less than 35 percent rock fragments in the particle-size control section.
DRAINAGE AND PERMEABILITY: Well drained; low, medium, or high surface runoff; moderate permeability (moderately high or high saturated hydraulic conductivity).
USE AND VEGETATION: Oest soils are used principally for rangeland, recreation, and urban development. The vegetation is principally Wyoming big sagebrush, antelope bitterbrush, bottlebrush squirreltail, and cheatgrass.
DISTRIBUTION AND EXTENT: Western Nevada and eastern California. These soils are not extensive with about 8,700 acres of the series mapped to date. MLRA 26.
MLRA OFFICE RESPONSIBLE: Reno, Nevada.
SERIES ESTABLISHED: Washoe County (South Part), Nevada, 1980.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 14 inches (A horizon).
Argillic horizon - The zone from 14 to 40 inches (Bt1 and Bt2 horizons).
Particle-size control section - The zone from 14 to 34 inches (Bt1 horizon and part of the Bt2 horizon).