LOCATION TUFFO                   NV+CA

Established Series
Rev. JBF/TM/JVC
12/2019

TUFFO SERIES

The Tuffo series consists of very shallow and shallow, somewhat excessively drained soils that formed in residuum derived from tuff and tuffaceous sandstone. Tuffo soils are on rock pediments, ash flows, and hills. Slopes are 4 to 50 percent. The mean annual precipitation is about 250 mm and the mean annual temperature is about 8 degrees C.

TAXONOMIC CLASS: Ashy, glassy, nonacid, mesic, shallow Vitrandic Torriorthents

TYPICAL PEDON: Tuffo ashy fine sandy loam--rangeland. (Colors are for dry soil unless otherwise noted.) The soil surface is partially covered with 10 percent gravel.

A--0 to 8 cm; pale brown (10YR 6/3) ashy fine sandy loam, dark brown (10YR 3/3) moist; moderate medium and thick platy structure; soft, very friable, nonsticky and nonplastic; common very fine, few fine and medium roots; many very fine and common fine vesicular pores; 5 percent gravel; slightly alkaline (pH 7.4); abrupt smooth boundary. (3 to 15 cm thick)

C--8 to 28 cm; light yellowish brown (10YR 6/4) ashy very fine sandy loam, brown (10YR 4/3) moist; massive; slightly hard, very friable, nonsticky and nonplastic; many very fine, common fine and few medium roots; common very fine tubular pores; 5 percent gravel; slightly alkaline (pH 7.4); clear smooth boundary. (8 to 23 cm thick)

Cr1--28 to 58 cm; highly weathered and fractured tuffaceous sandstone; few fine roots in fractures; gradual wavy boundary.

Cr2--58 to 107 cm; weathered and fractured tuffaceous sandstone; common pendants of secondary carbonates on bedding planes.

TYPE LOCATION: Elko County, Nevada; about 1.5 miles north of the Reed Station turnoff along State Highway 226; approximately 2,335 feet south and 2,540 feet east of the northwest corner of section 8, T. 38 N., R.54 E.; USGS Reed Station 7.5 minute topographic quadrangle; latitude 41 degrees 12 minutes 00 seconds N and longitude 115 degrees 55 minutes 15 seconds W; WGS84 Decimal Degrees 41.2000000 latitude, -115.9208333 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually moist in winter and spring, dry from late June through October; aridic moisture regime that borders on xeric.
Mean annual soil temperature: 8 to 11 degrees C.
Depth to bedrock: 10 to 38 cm to a paralithic contact. The paralithic materials below the contact are tuff or tuffaceous sedimentary rocks.
Volcanic glass content: 60 to 75 percent in coarse silt through sand fractions and 30 to 60 percent of the fine-earth fraction.
Reaction: Neutral or slightly alkaline.

Particle-size control section - Clay content: 5 to 15 percent.
Rock fragments: 5 to 25 percent, mainly gravel.

A horizon
Value: 5 through 7 dry, 3 or 4 moist.
Chroma: 2 through 4, dry or moist.

C horizon - Hue: 2.5Y or 10YR.
Value: 6 or 7 dry, 4 or 5 moist.
Chroma: 2 through 4, dry or moist.
Texture: Dominantly ashy very fine sandy loam or ashy fine sandy loam with gravelly ashy sandy loam in some pedons.

Cr layer
Identifiable secondary carbonates: Few to common seams along fracture planes.
Weathering: Highly weathered material in the upper part, to soft weathered material in the lower part.

COMPETING SERIES: This is the Porterfield series.

Porterfield soils have a C horizon with 35 to 60 percent rock fragments.

GEOGRAPHIC SETTING: Tuffo soils are on rock pediments, ash flows, and hills. The soils formed in residuum derived from tuff and tuffaceous sandstone. Slopes are 4 to 50 percent. Elevations range from 1,440 to 2,135 meters. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 200 to 300 mm, the mean annual temperature is 7 to 10 degrees C, and the frost-free period is 100 to 120 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Gochea, Wieland, and Yuko soils. Gochea soils have Mollic epipedons and argillic horizons. Wieland soils have clay textured argillic horizons. Yuko soils have argillic horizons that average 27 to 35 percent clay.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat excessively drained; high or very high surface runoff; high saturated hydraulic conductivity.

USE AND VEGETATION: Tuffo soils are used for rangeland and wildlife habitat. The vegetation is mainly Wyoming big sagebrush, antelope bitterbrush, Douglas rabbitbrush, Thurber's needlegrass, and bluebunch wheatgrass.

DISTRIBUTION AND EXTENT: Northern Nevada and northeastern California. These soils are moderately extensive. The series concept and about half the mapped acreage is in MLRA 25, while half the acreage occurs in MLRA 23.

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

SERIES ESTABLISHED: Elko County, Nevada (Central Part), 1986.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 18 cm (A and part of the C horizon).
Paralithic contact - The boundary at 28 cm to underlying soft, weathered bedrock (Cr1 layer).
Particle-size control section and ashy substitute class with glassy mineralogy - The zone from the soil surface to 28 cm (A and C horizons).

ADDITIONAL DATA: A reference pedon of Tuffo has partial characterization data by the Soil Survey Laboratory (SSL), Lincoln, NE, as soil survey sample number S83NV-007-000 (pedon # 84P0486). Selected data such as particle-size distribution and sand mineralogy are available.

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National Cooperative Soil Survey
U.S.A.