LOCATION PLACERITOS              NV

Established Series
Rev. ELS-RLB-JVC-JBF
05/2016

PLACERITOS SERIES

The Placeritos series consist of very deep, moderately well drained soils that formed in alluvium derived from mixed rocks. Placeritos soils are on stream terraces. Slopes are 0 to 2 percent. The mean annual precipitation is about 150 mm and the mean annual temperature is about 11 degrees C.

TAXONOMIC CLASS: Fine-silty, mixed, superactive, calcareous, mesic Oxyaquic Torrifluvents

TYPICAL PEDON: Placeritos loam--cultivated. (Colors are for dry soil unless otherwise noted).

Ap--0 to 18 cm; light brownish gray (10YR 6/2) loam, dark brown (10YR 3/3) moist; weak medium and coarse subangular blocky structure parting to weak fine granular; slightly hard, friable, slightly sticky and slightly plastic; few fine and medium roots; strongly effervescent; strongly alkaline (pH 8.7); clear smooth boundary. (10 to 23 cm thick)

C1--18 to 56 cm; light gray (2.5Y 7/2) silt loam, grayish brown (2.5Y 5/2) moist; moderate medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; many fine, and few medium roots; few fine and medium tubular pores; few fine faint brown (10YR 4/3) masses of iron accumulation along root channels; strongly effervescent; moderately alkaline (pH 8.4); clear smooth boundary. (23 to 50 cm thick)

C2--56 to 79 cm; light gray (5Y 7/2) very fine sandy loam, light brownish gray (2.5Y 6/2) moist; massive; slightly hard, very friable, slightly sticky and slightly plastic; few fine roots; common medium, fine and very fine tubular pores; few fine distinct light yellowish brown (10YR 6/4) and brown (10YR 4/3) masses of iron accumulation along root channels; common mica sand grains; strongly effervescent; moderately alkaline (pH 8.4); abrupt smooth boundary. (0 to 30 cm thick)

C3--79 to 109 cm; light gray (2.5Y 7/2) very fine sandy loam, grayish brown (2.5Y 5/2) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few fine roots; common medium, fine, and very fine tubular pores; common fine faint brown (10YR 4/3) masses of iron accumulation along root channels; common mica sand grains; strongly effervescent; strongly alkaline (pH 8.6); clear smooth boundary. (0 to 36 cm thick)

C4--109 to 147 cm; light brownish gray (2.5Y 6/2) silt loam, dark grayish brown (2.5Y 4/2) moist; massive; hard, friable, slightly sticky and slightly plastic; few fine roots; few medium and fine tubular pores; many medium distinct light brownish gray (2.5Y 6/2) lenses and spots and few lenses of black (N 2/0) organic matter; strongly effervescent; strongly alkaline (pH 9.0); clear wavy boundary. (0 to 46 cm thick)

C5--147 to 191 cm; light gray (2.5Y 7/2) silt loam, grayish brown (2.5Y 5/2) moist; massive; hard, friable, slightly sticky and slightly plastic; very few fine roots; few fine tubular pores; few tongues of very dark grayish brown (2.5Y 3/2) and very dark gray (N 3/0) material; common coarse light brownish gray (2.5Y 6/2) carbonate veins in root channels; few faint brown (10YR 4/3) masses of iron accumulation along root channels; strongly effervescent; strongly alkaline (pH 9.0).

TYPE LOCATION: Pershing County Nevada; about 1 mile east of Lovelock on a stream terrace above the Humboldt River; approximately 530 feet east and 100 feet north of the southwest corner of section 25, T. 27 N., R. 31 E.; USGS Lovelock 7.5 minute topographic quadrangle; latitude 40 degrees 10 minutes 23 seconds N and longitude 118 degrees 27 minutes 20 seconds W; WGS84 Decimal Degrees 40.1730556 latitude, -118.455556 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually moist in the moisture control section during late winter through early spring, dry during the late spring through early winter unless irrigated; typic aridic (torric) soil moisture regime.
Mean annual soil temperature: 11 to 12 degrees C.
Mean summer soil temperature: 21 to 22 degrees C.
Reaction: Moderately alkaline through very strongly alkaline.
Other features: Buried A horizons are in some pedons; an irregular decrease in organic carbon with depth is typical.

Particle-size control section - Clay content: Averages 18 to 27 percent.

Ap or A horizons
Hue: 10YR or 2.5Y.
Value: 5 through 7 dry, 3 through 5 moist; value of 5 dry and 3 moist are less than 10 cm thick or occur below 50 cm.
Chroma: 1 through 3, dry or moist; Chroma of 1 occur only in buried A horizons.

C horizons
Hue: 10YR through 5Y.
Value: 6 or 7 dry, 4 or 5 moist.
Chroma: 2 or 3, dry or moist.
Texture: Stratified very fine sandy loam to silty clay loam; thin strata of loam, fine sandy loam, or silty clay can occur in upper C horizons and texture of clay to sand can occur in lower C horizons.
Structure: Massive but can have weak or moderate, coarse to fine subangular blocky, or weak thick platy structure.
Calcium carbonate equivalent: 5 to 10 percent and is mainly disseminated. Few to common fine segregated seams and filaments of carbonates can occur in the C horizons of some pedons, and a few small carbonate concretions can occur in the lower horizons.
Sodicity (SAR): 13 to 30.

COMPETING SERIES: There are currently no other series in this family.

GEOGRAPHIC SETTING: Placeritos soils are on stream terraces. These soils formed in alluvium derived from mixed rocks that are dominantly basalt, tuff, limestone, and rhyolite. Slopes are 0 to 2 percent. Elevations range from 1,190 to 1,220 meters. The climate is arid with cool, moist winters and warm, dry summers. The mean annual precipitation is 125 to 180 mm, the mean annual temperature is 10 to 11 degrees C, and the frost-free period is 120 to 140 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Isolde and Sonoma soils. Isolde soils are sandy. Sonoma soils have an aquic moisture regime.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Moderately well drained; negligible surface runoff; moderately high saturated hydraulic conductivity. Endosaturation is present with an apparent seasonal high water table between 120 and 150 cm (deep free water occurrence class) between July and August. Cumulative annual duration class is Transitory. A drained phase is recognized.

USE AND VEGETATION: Placeritos soils are cultivated to small grains, alfalfa, and corn silage. Uncultivated areas are used for rangeland and dominantly have inland saltgrass, black greasewood, and fourwing saltbush.

DISTRIBUTION AND EXTENT: Western Nevada. These soils are not extensive with about 3,700 acres of the series mapped to date. MLRA 27.

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

SERIES ESTABLISHED: Pershing County (Lovelock Area), Nevada, 1963.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 18 cm (Ap horizon).
Endosaturation feature - The condition of ground water with an upper boundary between 120 and 150 cm
Particle-size control section - The zone from 25 to 100 cm (C2 horizon and parts of the C1 and C3 horizons).

The revision of April 2006 updated the taxonomic class from Fine-silty, mixed, superactive, calcareous, mesic Oxyaquic Xerofluvents based on the moisture regime being torric instead of xeric. Placeritos components in Box Elder County Utah are now correlated to the Beariver series. A Placeritos component in Elko County, Nevada needs correlation to another series.

ADDITIONAL DATA: There are several pedons of Placeritos 56NV027011 (pedon # 40A3205) and 56NV027012 (pedon # 40A3206) which now plot within polygons of Swingler map units. They are published in Soil Survey Investigations Report No. 23 on pages 122-125.

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National Cooperative Soil Survey
U.S.A.