LOCATION FORTANK                 NV

Established Series
Rev. RGB/RAF/GJS/JBF
01/2023

FORTANK SERIES

The Fortank series consists of moderately deep, well drained soils that formed in residuum derived from andesite, rhyolite and quartzite. These soils are on low hill and mountain side slopes. Slopes are 4 to 50 percent. Mean annual precipitation is about 230 mm and the mean annual temperature is about 7 degrees C.

TAXONOMIC CLASS: Fine, smectitic, frigid Xeric Haplargids

TYPICAL PEDON: Fortank gravelly loam--rangeland. (Colors are for dry soil unless otherwise noted.) The surface is covered by 5 percent cobbles and 40 percent gravel.

A1--0 to 13 cm; pale brown (10YR 6/3) gravelly loam, dark brown (10YR 3/3) moist; moderate medium and thick platy structure; soft, very friable, slightly sticky and slightly plastic; many very fine roots; many very fine vesicular and tubular, few fine tubular pores; 30 percent gravel; moderately alkaline (pH 8.0); abrupt smooth boundary. (8 to 15 cm thick)

A2--13 to 25 cm; pale brown (10YR 6/3) gravelly loam, brown (10YR 4/3) moist; weak very thin platy structure; soft, very friable, moderately sticky and moderately plastic; many very fine and few fine roots; many very fine vesicular pores; l5 percent gravel; moderately alkaline (pH 8.4); clear smooth boundary. (8 to 15 cm thick)

Bt1--25 to 36 cm; pale brown (10YR 6/3) gravelly clay loam, brown (10YR 4/3) moist; weak medium and coarse angular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; common very fine and fine, few medium roots; many very fine and few fine tubular pores; many faint clay films lining pores; 30 percent gravel; moderately alkaline (pH 8.4); clear wavy boundary. (8 to 13 cm thick)

Bt2--36 to 61 cm; brown (10YR 5/3) gravelly clay, brown (7.5YR 5/4) moist; moderate medium prismatic structure parting to moderate medium angular blocky; hard, friable, very sticky and very plastic; few very fine, fine and medium roots; many very fine tubular pores; continuous faint clay films on ped faces and lining pores; 25 percent gravel; moderately alkaline (pH 8.4); clear wavy boundary. (20 to 28 cm thick)

Btk--61 to 89 cm; brown (7.5YR 5/4) gravelly clay, brown (7.5YR 4/4) moist; weak medium prismatic structure parting to moderate medium angular blocky; hard, friable, very sticky and very plastic; few very fine roots; many very fine tubular and interstitial pores; continuous distinct clay films lining pores and on ped faces; many fine carbonate filaments; 25 percent gravel; strongly effervescent; moderately alkaline (pH 8.4); abrupt smooth boundary. (20 to 30 cm thick)

Cr--89 cm; soft, weathered andesitic tuff.

TYPE LOCATION: Eureka County, Nevada; approximately 7 miles east of Crescent Valley; about 2,100 feet south and 500 feet west of the approximate northeast corner of section 33, T. 30 N., R. 49 E.; USGS Tumbleweed Flat 7.5 minute topographic quadrangle; latitude 40 degrees 25 minutes 57 seconds N and longitude 116 degrees 27 minutes 14 seconds W; WGS84 Decimal Degrees 40.4325000latitude, -116.4372222 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually dry, moist in winter and spring, dry mid June through October; aridic soil moisture regime bordering on xeric.
Mean annual soil temperature: 7 to 8 degrees C.
Depth to bedrock: 76 to 100 cm.

Particle-size control section - Clay content: 35 to 45 percent.
Rock fragments: l5 to 35 percent, dominantly gravel.

A horizon
Value: 3 or 4 moist.
Structure: Weak or moderate, very thin through thick platy or subangular blocky.
Reaction: Slightly alkaline or moderately alkaline.

Bt horizon
Hue: 7.5YR or l0YR.
Value: 5 or 6 dry, 4 or 5 moist.
Chroma: 3 or 4.
Texture: Clay loam or clay.
Structure: Weak or moderate, angular blocky or prismatic.

COMPETING SERIES: These are the Bucan and Deseed series.

Bucan soils have a lithic contact at a depth of 100 to 150 cm. Deseed soils are neutral and have a lithic contact at a depth of 50 to 76 cm.

GEOGRAPHIC SETTING: Fortank soils are on hill and mountain side slopes. These soils formed in residuum derived from andesite, rhyolite and quartzite. Slopes are 4 to 50 percent. Elevations are 1,525 to 2,290 meters. The climate is semiarid with cool, moist winters and warm, dry summers. Mean annual precipitation is 200 to 250 mm; mean annual temperature is 6 to 7 degrees C., and the frost-free season is 80 to l00 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bregar, Softscrabble and Soughe soils. Bregar, Softscrabble and Soughe soils are loamy-skeletal. Also, Bregar and Soughe soils are shallow to bedrock and Softscrabble soils are very deep.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; moderate or rapid runoff; moderately low saturated hydraulic conductivity.

USE AND VEGETATION: Livestock grazing and wildlife habitat. The vegetation is principally Wyoming big sagebrush, spiny hopsage, Douglas rabbitbrush, bottlebrush squirreltail, Sandberg bluegrass, Thurber needlegrass and buckwheat.

DISTRIBUTION AND EXTENT: Northeastern Nevada. These soils are not extensive. MLRA 28B.

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

SERIES ESTABLISHED: Eureka County Area, Nevada, 1983.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the surface to 25 cm (A1 and A2 horizons).
Argillic horizon - The zone from about 25 to 89 cm (the Bt1, Bt2, and Btk horizons).
Paralithic contact - The boundary at about 89 cm (the Cr horizon).
Particle-size control section - The zone from about 25 to 75 cm (the Bt1 and Bt2 horizons and part of the Btk horizon).

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National Cooperative Soil Survey
U.S.A.