LOCATION WEEZWEED                NV+CA

Established Series
Rev. JBF/EWB/TM/JVC
01/2020

WEEZWEED SERIES

The Weezweed series consists of very deep, moderately well drained soils that formed in alluvium derived from pyroclastic volcanic rocks. Weezweed soils are on stream terraces. Slopes are 0 to 2 percent. The mean annual precipitation is about 300 mm and the mean annual temperature is about 8 degrees C.

TAXONOMIC CLASS: Ashy, glassy, mesic Vitritorrandic Haploxerolls

TYPICAL PEDON: Weezweed ashy loam--rangeland. (Colors are for dry soil unless otherwise noted).

A1--0 to 13 cm; grayish brown (10YR 5/2) ashy loam, very dark grayish brown (10YR 3/2) moist; moderate thick platy structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and fine roots; common very fine tubular and interstitial pores; neutral (pH 6.8); clear wavy boundary. (5 to 15 cm thick)

A2--13 to 30 cm; grayish brown (10YR 5/2) ashy loam, very dark grayish brown (10YR 3/2) moist; weak coarse prismatic structure parting to moderate coarse subangular blocky; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and fine roots; common very fine tubular pores; neutral (pH 6.8); clear wavy boundary. (15 to 30 cm thick)

A3--30 to 41 cm; grayish brown (10YR 5/2) ashy loam, very dark grayish brown (10YR 3/2) moist; weak coarse prismatic structure parting to strong fine and medium subangular blocky; slightly hard, very friable, slightly sticky and slightly plastic; common very fine, fine and medium roots; common very fine tubular pores; common thin dark gray (10YR 4/1) strata, black (10YR 2/1) moist; neutral (pH 6.8); clear wavy boundary. (10 to 30 cm thick)

C1--41 to 66 cm; light brownish gray (10YR 6/2) finely stratified ashy sandy loam, dark grayish brown (10YR 4/2) moist; moderate coarse prismatic structure parting to strong thick platy; very hard, friable, slightly sticky and slightly plastic; few very fine through medium roots; few very fine tubular pores; common medium distinct dark yellowish brown (10YR 3/4) relict masses of iron accumulation, black (10YR 2/1) moist; neutral (pH 6.7); clear wavy boundary. (20 to 38 cm thick)

C2--66 to 107 cm; light brownish gray (10YR 6/2) stratified ashy loam and ashy sandy clay loam, dark grayish brown (10YR 4/2) moist; moderate coarse prismatic structure parting to strong thick platy; very hard, firm, moderately sticky and slightly plastic; few very fine through medium roots; few very fine tubular pores; few fine distinct dark yellowish brown (10YR 3/4) moist relict masses of iron accumulation and few fine faint black (10YR 2/1) moist relict masses of manganese accumulation; slightly acid (pH 6.4); clear wavy boundary. (5 to 46 cm thick)

C3--107 to 152 cm; light yellowish brown (2.5Y 6/3) stratified ashy loam and ashy sandy clay loam, olive brown (2.5Y 4/3) moist; massive; very hard, firm, moderately sticky and slightly plastic; few very fine roots; common very fine tubular pores; common fine distinct black (10YR 2/1) moist relict masses of manganese accumulation and common fine faint light olive brown (2.5Y 5/3) moist relict masses of iron accumulation; neutral (pH 6.6).

TYPE LOCATION: Washoe County, Nevada; about 0.5 miles south-southwest of the Wall Canyon Ranch and just south of the Sheldon National Wildlife Refuge boundary; approximately 100 feet south and 1,300 feet west of the northeast corner of section 4, T. 42 N., R. 23 E.; USGS Nut Mountain 7.5 minute topographic quadrangle; latitude 41 degrees 35 minutes 31.7 seconds N and longitude 119 degrees 23 minutes 12.3 seconds W; WGS84 Decimal Degrees 41.5921389 latitude, -119.3867500 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually moist in winter and spring, dry from mid-June through October; aridic soil moisture regime that borders on xeric.
Mean annual soil temperature: 8 to 10 degrees C.
Mollic epipedon thickness: 25 to 50 cm.
Volcanic glass content: 60 to 90 percent total in the very fine sand and fine sand fractions throughout; 25 to 50 percent is glass shards with the remainder as glass-coated grains and glass aggregates.
Other features: Organic matter decreases irregularly with depth. Some pedons have C horizons below depths of 36 inches with stratified textures of sandy loam to silty clay loam. Thin discontinuous strata having up to 35 percent volcanic gravel are present in some pedons.

Particle-size control section - Clay content: Averages 18 to 27 percent.
Rock fragments: Less than 10 percent, mainly gravel. Lithology of fragments are volcanic rocks such as rhyolitic tuff.

A horizons
Hue: 10YR or 2.5Y.
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 1 or 2, dry or moist.
Reaction: Neutral or slightly alkaline.
Organic matter content: 2 to 4 percent.

C horizons
Hue: 10YR through 5Y.
Value: 6 through 8 dry, 4 or 5 moist.
Chroma: 1 through 3, dry or moist.
Structure: Weak or moderate fine to coarse prismatic parting to platy or blocky or is massive.
Texture: Usually stratified gravelly ashy loamy sand to ashy silty clay loam; Averages ashy loam or ashy sandy clay loam when mixed.
Reaction: Neutral through moderately alkaline.
Redoximorphic features: Relic redox concentrations are present in most pedons.

COMPETING SERIES: These are the Bitner, Brays, Chelan, Deskamp, Dryhollow, Emagert, Kester, Surprise, Winblow, Yellowhills, Yotes, and Zark series.

Bitner and Zark soils are moderately deep to paralithic contacts. Brays, Deskamp, Kester, and Winblow soils are moderately deep to lithic contacts. Chelan soils are deep to duripans. Dryhollow, Surprise, and Yellowhills soils have less than 18 percent clay in the particle-size control section, have cambic horizons, do not have endosaturation within 180 cm of the soil surface, and have a regular decrease in organic matter content. Emagert soils have mollic epipedons greater than 60 cm thick. Yotes soils have 5 to 18 percent clay, 15 to 35 percent rock fragments, and horizons with up to 50 percent durinodes in the particle-size control section.

GEOGRAPHIC SETTING: Weezweed soils are on stream terraces. They formed in alluvium derived from pyroclastic volcanic rocks. Slopes are 0 to 2 percent. Elevations range from 1,460 to 1,890 meters. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 250 to 360 mm, the mean annual temperature is 7 to 8 degrees C., and the frost-free period is 80 to 100 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Emagert soil and the Wetvit soil. Wetvit soils have saturation within 46 cm of the soil surface.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Moderately well drained; low surface runoff; moderately high saturated hydraulic conductivity. Endosaturation is present with an apparent seasonal high water table between 150 and 180 cm (very deep free water occurrence class) between January and May. Cumulative annual duration class is Common. These soils are subject to rare flooding for very brief periods year-round.

USE AND VEGETATION: Weezweed soils are used for rangeland and wildlife habitat. The present vegetation is dominantly basin big sagebrush, rabbitbrush, and basin wildrye.

DISTRIBUTION AND EXTENT: Northwestern Nevada and northeastern California. These soils are not extensive with about 5,800 acres of the series mapped to date. MLRA 23.

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

SERIES ESTABLISHED: Washoe County, Nevada (North Part), 1995.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 44 cm (A1, A2, and A3 horizons).
Vitrandic intergrade feature - The zone from the soil surface to 76 cm (A1, A2, A3, C1 horizons and part of the C2 horizons).
Endosaturation feature - The condition of ground water with an upper boundary between 150 and 180 cm at certain times during normal years (part of the C3 horizon).
Particle-size control section and ashy substitute class with glassy mineralogy - The zone from 25 to 100 cm (A3, C1 and parts of the A2 and C2 horizons).

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National Cooperative Soil Survey
U.S.A.