LOCATION FORTANK NVEstablished Series
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 pebbles.
Al--0 to 5 inches; pale brown (l0YR 6/3) gravelly loam, dark brown (l0YR 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 pebbles; moderately alkaline (pH 8.0); abrupt smooth boundary. (3 to 6 inches thick)
A2--5 to l0 inches; pale brown (l0YR 6/3) gravelly loam, brown (l0YR 4/3) moist; weak very thin platy structure; soft, very friable, sticky and plastic; many very fine and few fine roots; many very fine vesicular pores; l5 percent pebbles; moderately alkaline (pH 8.4); clear smooth boundary. (3 to 6 inches thick)
Btl--l0 to l4 inches; pale brown (l0YR 6/3) gravelly clay loam, brown (l0YR 4/3) moist; weak medium and coarse angular blocky structure; slightly hard, friable, sticky and plastic; common very fine and fine, few medium roots; many very fine and few fine tubular pores; many thin clay films lining pores; 30 percent pebbles; moderately alkaline (pH 8.4); clear wavy boundary. (3 to 5 inches thick)
Bt2--l4 to 24 inches; brown (l0YR 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 and fine, few medium roots; many very fine tubular pores; continuous thin clay films on ped faces and lining pores; 25 percent pebbles; moderately alkaline (pH 8.4); clear wavy boundary. (8 to 11 inches thick)
Btk--24 to 35 inches; brown (7.5YR 5/4) gravelly clay, dark 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 moderately thick clay films lining pores and on ped faces; many fine lime filaments; 25 percent pebbles; strongly effervescent; moderately alkaline (pH 8.4); abrupt smooth boundary. (8 to l2 inches thick)
Cr--35 inches; soft, weathered andesitic tuff.
TYPE LOCATION: Eureka County, Nevada; approximately 7 miles east of Crescent Valley; about 2,l00 feet south and 500 feet west of the approximate northeast corner of section 33, T. 30 N., R. 49 E.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually dry, moist in winter and spring, dry mid June through October.
Soil temperature - 45 to 47 degrees F.
Solum thickness and depth to bedrock - 30 to 40 inches.
Control section - Texture of fine earth: Clay loam or clay. Rock fragments: l5 to 35 percent, dominantly pebbles. Clay content: 35 to 45 percent.
A horizon - Value: 3 or 4 moist. Structure: Weak or moderate, very thin through thick platy or subangular blocky. Reaction: Mildly alkaline or moderately alkaline.
Bt horizon - Hue: 7.5YR or l0YR. Value: 5 or 6 dry, 4 or 5 moist. Chroma: 3 or 4. Structure: Weak or moderate, angular blocky or prismatic.
COMPETING SERIES: These are the Bucan, Deseed and Handy series. Bucan soils have a lithic contact at a depth of 40 to 60 inches. Deseed soils are neutral and have a lithic contact at a depth of 20 to 30 inches. Handy soils have a Bk horizon with texture of loam through loamy sand and are more than 60 inches deep.
GEOGRAPHIC SETTING: Fortank soils are on low hill and mountain side slopes. These soils formed in residuum weathered from andesite, rhyolite and quartzite. Slopes are 4 to 50 percent. Elevations are 5,000 to 7,500 feet. The climate is semiarid with cool, moist winters and warm, dry summers. Mean annual precipitation is 8 to l0 inches; mean annual temperature is 43 to 45 degrees F., 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 PERMEABILITY: Well drained; moderate or rapid runoff; slow permeability.
USE AND VEGETATION: Rangeland 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 OFFICE RESPONSIBLE: Reno, Nevada
SERIES ESTABLISHED: Eureka County Area, Nevada, l983.
DIAGNOSTIC HORIZONS AND FEATURES RECOGNIZED IN THIS PEDON ARE:
Argillic horizon - The zone from about 10 to 35 inches (the Bt1, Bt2, and Btk horizons).
Paralithic contact - The boundary at about 35 inches (the Cr horizon).
Particle-size control section - The zone from about 10 to 30 inches (the Bt1 and Bt2 horizons and part of the Btk horizon).