LOCATION MALMESA                 NV

Established Series
Rev: TM/JBF/WED
06/2016

MALMESA SERIES

The Malmesa series consists of shallow to a duripan, well drained soils that formed in residuum derived from volcanic rocks mainly basalt. Malmesa soils are on mountain slopes, hills, mesas, and plateaus. Slopes are 2 to 30 percent. Mean annual precipitation is about 250 mm and mean annual temperature is about 12 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic, shallow Xeric Argidurids

TYPICAL PEDON: Malmesa very cobbly fine sandy loam--rangeland. (Colors are for dry soil unless otherwise noted.)

A--0 to 8 cm; pale brown (10YR 6/3) very cobbly fine sandy loam, dark brown (10YR 3/3) moist; moderate thin platy structure; soft, very friable, nonsticky and nonplastic; few very fine roots; many very fine and coarse vesicular pores; 30 percent gravel and 20 percent cobbles; slightly effervescent; moderately alkaline (pH 8.0); abrupt smooth boundary. (3 to 10 cm thick)

Bt--8 to 18 cm; light yellowish brown (10YR 6/4) very cobbly loam, brown (10YR 4/3) moist; moderate medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and medium roots; many very fine tubular and interstitial pores; 20 percent gravel, 15 percent cobbles; few faint clay films on faces of peds, common faint clay films bridging sand grains; slightly alkaline (pH 7.8); abrupt smooth boundary. (5 to 13 cm thick)

Btk--18 to 28 cm; light yellowish brown (10YR 6/4) very cobbly clay loam, dark yellowish brown (10YR 4/4) moist; moderate fine subangular blocky structure; slightly hard, very friable, moderately sticky and moderately plastic; common very fine and medium roots; many very fine tubular pores; 25 percent gravel and 25 percent cobbles; few faint clay films lining pores, many distinct clay films on faces of peds; few (1 percent) carbonate and silica pendants on bottom of rock fragments; violently effervescent; moderately alkaline (pH 8.4); clear wavy boundary. (8 to 30 cm thick)

Bqk--28 to 38 cm; light yellowish brown (10YR 6/4) extremely cobbly loam, dark yellowish brown (10YR 4/4) moist; massive; soft, very friable, nonsticky and slightly plastic; common very fine and medium roots; common very fine tubular pores; 35 percent gravel and 25 percent cobbles; 10 percent weathered pan fragments and carbonate and silica pendants on bottom of rock fragments; violently effervescent; strongly alkaline (pH 8.6); abrupt broken boundary. (5 to 13 cm thick)

Bqkm--38 to 41 cm; cemented duripan; thin (1 mm to 5 cm) indurated laminar cap plugs all fractures.

R--41 cm; fractured basalt.

TYPE LOCATION: Esmeralda County, Nevada, Malpais Mesa south of Pozo Canyon; about 2,000 feet north and 100 feet west of the southeast corner of section 15, T. 3 S., R. 42 E; USGS Goldfield 7.5 minute topographic quadrangle; latitude 37 degrees 40 minutes 34.8 seconds N and longitude 117 degrees 14 minutes 37.3 seconds W; WGS84 Decimal Degrees 37.6765000 latitude, -117.2438889 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Moist in winter and spring months, dry in summer and fall except for 10 to 20 days cumulative between July and September due to convection storms; aridic soil moisture regime that borders on xeric.
Mean annual soil temperature: 12 to 15 degrees C.
Depth to indurated pan: 36 to 50 cm.
Depth to bedrock: 36 to 50 cm.
Calcium carbonate equivalent: 0 to 20 percent in the material less than 2 mm.

Particle-size control section - Clay content: 27 to 35 percent.
Rock fragments: 35 to 50 percent, dominantly cobbles and gravel.

A horizon
Value: 6 or 7 dry, 3 through 5 moist.
Chroma: 2 or 3, dry or moist.
Carbonates: Noneffervescent to slightly effervescent.
Reaction: Slightly alkaline or moderately alkaline.

Bt horizon
Value: 5 or 6 dry, 4 or 5 moist.
Chroma: 3 or 4, dry or moist.
Texture: Loam or clay loam, subhorizons of clay or sandy clay loam are in some pedons.
Structure: Fine or medium subangular blocky.
Consistence: Soft or slightly hard dry.
Effervescence: Noneffervescent to slightly effervescent.
Reaction: Slightly alkaline or moderately alkaline.

Btk horizon
Value: 5 or 6 dry, 4 or 5 moist.
Chroma: 3 or 4, dry or moist.
Texture: Clay loam, subhorizons of loam, sandy clay loam or clay are in some pedons.
Consistence: Soft or slightly hard dry, slightly sticky or moderately sticky and slightly plastic or moderately plastic wet.
Effervescences: Strongly effervescent to violently effervescent.
Reaction: Slightly alkaline or moderately alkaline.

Bqk horizon
Value: 6 or 7 dry, 4 or 5 moist.
Chroma: 4 through 6, dry or moist.
Texture: Loam or sandy loam.
Clay content: 10 to 18 percent.
Rock fragments: 45 to 65 percent, mainly cobbles and gravel.
Structure: Massive or subangular blocky.
Consistence: Nonsticky or slightly sticky wet.
Effervescence: Strongly effervescent or violently effervescent.
Other features: This horizon commonly has many pan fragments and thick coatings on rock fragments.
Reaction: Moderately alkaline or strongly alkaline.

Bqkm horizon
Usually a thin 1 mm to 5 cm thick laminar cap coating bedrock.

COMPETING SERIES: These are the Brock, Cleet, Deepeek, Hotcreek, Lapon, Oleman, Shinnpeak, Troughs, Vinini and Wanapum series.

Brock and Deepeek soils lack bedrock within 100 cm. Cleet soils have 18 to 25 percent clay in the particles-size control section. Hotcreek and Lapon soils have a duripan at a depth of less than 36 cm. Oleman soils were formed in alluvium dominantly from ignimbrite, rhyolite and limestone. Shinnpeak soils lack summer precipitation. Troughs soils lack bedrock within 50 cm and have a duripan more than 13 cm thick. Vinini and Wanapum soils have bedrock at greater than 50 cm.

GEOGRAPHIC SETTING: Malmesa soils are on hills, mountain slopes, mesas and plateaus. These soils formed in residuum from volcanic rocks; mainly basalt. Slopes are 2 to 30 percent. Elevations are 1,375 to 2,290 meters. The mean annual temperature is 11 to 14 degrees C, mean annual precipitation is 200 to 250 mm, and the frost-free season is 120 to 150 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Stewval, and Tokoper series. Stewval soils lack an indurated duripan. Tokoper soils are typic aridic and have a duripan at less than 36 cm.

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

USE AND VEGETATION: Malmesa soils are used for livestock grazing and wildlife habitat. The present vegetation is mainly Wyoming big sagebrush, bottlebrush squirreltail, galleta, Indian ricegrass, Nevada ephedra and scattered Joshua trees.

DISTRIBUTION AND EXTENT: Southern Nevada. These soils are not extensive. MLRA 29.

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

SERIES ESTABLISHED: Esmeralda County, Nevada, 1984.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the surface to 8 cm (A horizon).
Argillic horizon - The zone from about 8 to 28 cm (Bt and Btk horizons).
Duripan - The zone from 38 to 41 cm (Bqkm horizon).
Lithic contact - The boundary at 41 cm (R horizon).
Particle-size control section - The zone from 8 to 28 cm (Bt, and Btk horizons).

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National Cooperative Soil Survey
U.S.A.