LOCATION TOCAN                   NV

Established Series
Rev. WMA/RPZ/JVC/JBF
05/2016

TOCAN SERIES

The Tocan series consists of very deep, well drained soils that formed in alluvium derived from mixed rocks. Tocan soils are on fan remnants and beach terraces. Slopes are 0 to 8 percent. The mean annual precipitation is about 150 mm and the mean annual temperature is about 10 degrees C.

TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Durinodic Haplargids

TYPICAL PEDON: Tocan gravelly sandy loam--rangeland. (When described, the soil was dry throughout. Colors are for dry soil unless otherwise noted.)

A--0 to 15 cm; pale brown (10YR 6/3) gravelly sandy loam, brown (10YR 4/3) moist; weak fine granular structure; soft, very friable, slightly sticky and nonplastic; many fine and very fine roots; many very fine interstitial pores; 15 percent gravel; slightly alkaline (pH 7.4); abrupt smooth boundary. (8 to 18 cm thick)

Bt1--15 to 25 cm; very pale brown (10YR 7/3) loam, brown (10YR 5/3) moist; weak coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common coarse and medium and many fine and very fine roots; few fine and many very fine tubular pores; few faint clay films on faces of peds and lining pores; 10 percent gravel; slightly alkaline (pH 7.8); abrupt wavy boundary. (8 to 15 cm thick)

Bt2--25 to 38 cm; yellowish brown (10YR 5/4) gravelly sandy clay loam, dark yellowish brown (10YR 4/4) moist; moderate medium and fine subangular blocky structure; hard, firm, moderately sticky and moderately plastic; common coarse and medium and many fine and very fine roots; many fine and very fine tubular pores; common faint clay films on faces of peds, lining pores, and bridging sand grains; 20 percent gravel; moderately alkaline; (pH 8.4); clear wavy boundary. (10 to 25 cm thick)

Bq--38 to 81 cm; pale brown (10YR 6/3) gravelly sandy loam, brown (10YR 4/3) moist; weak coarse subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; few coarse and medium and common fine and many very fine roots; many fine and very fine tubular pores; 30 percent durinodes, firm moist and very hard dry; 30 percent gravel; strongly alkaline (pH 8.6); clear wavy boundary. (25 to 60 cm thick)

C--81 to 112 cm; light brownish gray (10YR 6/2) extremely gravelly loamy coarse sand, very dark grayish brown (10YR 3/2) moist; single grain; loose, nonsticky and nonplastic; few medium and common fine and very fine roots; many fine and very fine interstitial pores; 60 percent gravel; strongly effervescent under sides of gravel; moderately alkaline (pH 8.4); abrupt broken boundary. (0 to 30 cm thick)

Bqkb--112 to 130 cm; pale brown (10YR 6/3) sandy loam, brown (10YR 4/3) moist; massive; hard, firm, nonsticky and nonplastic; few fine and very fine roots; common very fine tubular pores; weakly silica-cemented continuous brittle matrix; 10 percent gravel; violently effervescent; strongly alkaline; (pH 8.8); abrupt wavy boundary. (0 to 30 cm thick)

C--130 to 152 cm; light brownish gray (10YR 6/2) very gravelly sand, very dark grayish brown (10YR 3/2) moist; single grain; loose, nonsticky and nonplastic; few fine and very fine roots; many fine and very fine interstitial pores; 40 percent gravel; moderately alkaline (pH 8.4).

TYPE LOCATION: Lyon County, Nevada; 8 miles south of Yerington; 600 feet south and 750 feet west of the northeast corner of section 33, T. 12 N., R. 25 E.; USGS Wilson Canyon 7.5 minute topographic quadrangle; latitude 38 degrees 51 minutes 56 seconds N and longitude 119 degrees 11 minutes 04 seconds W; WGS84 Decimal Degrees 38.8655361 latitude, -119.1844444 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Moist in winter and early spring, dry from late spring through fall; typic aridic moisture regime.
Mean annual soil temperature: 12 to 13 degrees C.
Depth to base of argillic horizon and upper zone of silica accumulation: 30 to 46 cm.

Particle-size control section - Clay content: 20 to 28 percent.
Rock fragments: 0 to 20 percent gravel. Lithology of fragments is mixed.

A horizon
Value: 6 or 7 dry, 3 or 4 moist.
Chroma: 2 or 3.
Reaction: Neutral to moderately alkaline.

Bt horizons
Hue: 10YR or 7.5YR.
Value: 5 through 7 dry, 4 or 5 moist.
Chroma: 3 or 4.
Texture: Gravelly loam, gravelly sandy clay loam, or sandy clay loam.
Reaction: Neutral to moderately alkaline.


Bq, Bqk, and C horizons
Texture: Stratified loam to very gravelly sand.
Reaction: Moderately alkaline or strongly alkaline.
Effervescence: Noneffervescent to strongly effervescent.
Calcium carbonate equivalent: 0 to 5 percent.
Other features: 20 to 80 percent durinodes in Bq or Bqk horizons, mostly small and medium, slightly hard to very hard.

COMPETING SERIES: These are the Caudle, Nyala, Unsel, and Vigus series.

Caudle, Nyala, and Unsel soils have identifiable secondary carbonates in parts of the argillic horizon. In addition, Nyala and Unsel soils have 27 to 35 percent clay in the particle-size control section. Vigus soils are intermittently moist in the upper part of the moisture control section for 10 to 20 days cumulative between July and October and have mean annual soil temperature of 12 to 15 degrees C.

GEOGRAPHIC SETTING: Tocan soils are on fan remnants and beach terraces. They formed in alluvium derived from mixed rocks. Slopes are 0 to 8 percent. Elevations range from 1,340 to 1,524 meters. The climate is cool-arid with cool, moist winters and hot, dry summers. The mean annual precipitation is 100 to 150 mm, the mean annual temperature is 10 to 11 degrees C., and the frost-free period is 100 to 130 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Perazzo, Pizene, and Yerington soils. Perazzo soils are loamy-skeletal and have argillic horizons. Pizene soils are fine-loamy and have natric horizons. Yerington soils are sandy and do not have diagnostic subsurface horizons.

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

USE AND VEGETATION: Tocan soils are used for rangeland and wildlife habitat. Some areas are used for cultivated crops and urban development. The vegetation is mainly Indian ricegrass, Bailey greasewood, and shadscale.

DISTRIBUTION AND EXTENT: Western Nevada. These soils are moderately extensive. MLRA 27.

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

SERIES ESTABLISHED: Lyon County Area, Nevada, 1981.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 15 cm (A horizon).
Argillic horizon - The zone from 15 to 38 cm (Bt1 and Bt2 horizons).
Duric feature - The zone from 38 to 81 cm (Bq horizon).
Particle-size control section - The zone from 15 to 38 cm (Bt1 and Bt2 horizons).

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National Cooperative Soil Survey
U.S.A.