LOCATION DELVADA                 NV

Established Series
Rev. MTS-TM-JVC-JBF
02/2016

DELVADA SERIES

The Delvada series consists of very deep, very poorly drained soils that formed in alluvium derived from mixed rocks. Delvada soils are on flood plains and stream terraces. Slopes are 0 to 2 percent. The mean annual precipitation is about 230 mm and the mean annual temperature is about 9 degrees C.

TAXONOMIC CLASS: Fine, smectitic, calcareous, mesic Cumulic Vertic Endoaquolls

TYPICAL PEDON: Delvada silty clay--irrigated pasture. (Colors are for moist soil unless otherwise noted.)

Ap--0 to 15 cm; black (10YR 2/1) silty clay, variegated dark grayish brown (10YR 4/2) and very dark gray (10YR 3/1) dry; moderate medium platy structure; very hard, firm, moderately sticky and very plastic; many very fine and fine and few medium roots; many very fine and fine tubular pores; many worm channels and casts; strongly alkaline (pH 8.6); clear smooth boundary. (0 to 20 cm thick)

Ag1--15 to 33 cm; black (10YR 2/1) silty clay, variegated grayish brown (10YR 5/2) and very dark gray (10YR 3/1) dry; moderate medium prismatic structure parting to moderate medium subangular blocky; hard, friable, very sticky and very plastic; many very fine and fine and few medium roots; many very fine and fine tubular pores; many worm channels and casts; slightly effervescent; strongly alkaline (pH 8.6); clear wavy boundary. (14 to 25 cm thick)

Ag2--33 to 43 cm; black (10YR 2/1) silty clay, gray (10YR 5/1) dry; few fine prominent yellowish brown (10YR 5/6) redox concentrations; moderate medium prismatic structure parting to moderate medium subangular blocky; hard, friable, very sticky and very plastic; common very fine, fine and medium roots; many very fine and fine tubular pores; many worm channels and casts; slightly effervescent; strongly alkaline (pH 8.6); clear wavy boundary. (8 to 25 cm thick)

Ag3--43 to 74 cm; black (10YR 2/1) silty clay, gray (10YR 5/1) dry; strong coarse prismatic structure parting to moderate medium subangular blocky; hard, firm, very sticky and very plastic; common very fine and fine roots; many very fine and fine tubular pores; few fine prominent dark reddish brown (5YR 3/4) masses of manganese accumulation and common fine and medium brown (7.5YR 4/4) masses of iron accumulation; many worm channels and casts; few fine violently effervescent carbonate filaments; slightly effervescent matrix; moderately alkaline (pH 8.4); clear wavy boundary. (8 to 38 cm thick)

Bkg--74 to 140 cm; variegated dark grayish brown (2.5Y 4/2) and very dark grayish brown (2.5Y 3/2) silty clay, gray (10YR 6/1) dry; weak coarse prismatic structure parting to moderate medium subangular blocky; hard, firm, very sticky and very plastic; few very fine and fine roots; many very fine and fine tubular pores; common thin silt coats lining pores; many worm channels and casts; many fine through coarse black (10YR 2/1) manganese stains in irregular pattern; few fine black (10YR 2/1) manganese concretions; common fine soft violently effervescent carbonate filaments; slightly effervescent matrix; moderately alkaline (pH 8.2); gradual wavy boundary. (25 to 90 cm thick)

Cg--140 to 152 cm; dark grayish brown (2.5Y 4/2) silty clay loam, gray (10YR 6/1) dry; massive; hard, friable, moderately sticky and moderately plastic; many very fine and fine and common medium tubular pores; slightly effervescent; moderately alkaline (pH 8.4).

TYPE LOCATION: Humboldt County, Nevada; approximately 1 mile west and 12 miles south of Paradise Valley; about 2,490 feet south and 2,490 feet east of the northwest corner of section 26, T. 40 N., R. 39 E.; USGS Willow Point 7.5 minute topographic quadrangle; latitude 41 degrees 19 minutes 01 seconds N and longitude 117 degrees 33 minutes 12 seconds W; WGS84 Decimal Degrees 41.3169444 latitude, -117.5533333 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Saturated within 30 cm of the soil surface for 1 to 3 months; continuously saturated within 150 cm of the surface.
Mean annual soil temperature: 8 to 11 degrees C.
Mollic epipedon thickness: 60 to 100 cm.
Depth to effervescence: 0 to 20 cm.
Salininity (EC): Greater 2 mmhos/cm in some horizon within 100 cm.

Particle-size control section - Clay content: 40 to 50 percent.
Sand content: Less than 15 percent.

A horizons
Hue: 10YR or 2.5Y.
Value: 3 through 5 dry, 2 or 3 moist.
Chroma: 1 or 2, moist or dry.
Reaction: Moderately alkaline through very strongly alkaline (up to pH 9.6).
Redoximorphic features: Distinct or prominent redox concentrations are common in the lower subhorizons of most pedons.
Other features: Worm casts are common in upper profile.
Organic matter content: 1 to 5 percent.

Bkg horizons
Hue: 10YR or 2.5Y.
Value: 6 or 7 dry, 3 through 5 moist.
Chroma: 1 or 2, moist or dry.
Structure: Prismatic or subangular blocky.
Consistence: Friable or firm, moist.
Reaction: Moderately alkaline through very strongly alkaline (up to pH 9.6).
Redoximorphic features: Few to many, faint redox concentrations are common in some pedons; Manganese concretions are common in most pedons.
Calcium carbonate equivalent: 1 to 10 percent.

Cg horizon
Hue: 2.5Y or 10YR.
Value: 6 or 7 dry, 3 through 5 moist.
Chroma: 1 or 2, moist or dry.
Texture: Silty clay or silty clay loam.
Clay content: 30 to 50 percent.
Consistence: Firm or friable moist.
Redoximorphic features: Few, fine, distinct redox concentrations are common in some pedons.

COMPETING SERIES: These are the Baltic, Holly Springs, James, Knoke and Nishna series.

Baltic soils have accumulations of gypsum in the lower part of the particle-size control section. Holly srings have a Cg with more than 50 percent clay. James soils have visible accumulations of salt in upper horizons and accumulations of secondary gypsum in lower subhorizons. Knoke soils average less than 40 percent clay in the particle-size control section.

GEOGRAPHIC SETTING: Delvada soils are on flood plains and stream terraces. These soils formed in alluvium derived from mixed rocks. Slopes are 0 to 2 percent. Elevations range from 1,250 to 1,525 meters. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 200 to 250 mm, mean annual temperature is 7 to 11 degrees C, and the frost-free period is 100 to 130 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Humboldt and Paranat series. Both soils have a mollic epipedon that is less than 60 cm thick. In addition, Paranat soils are fine-silty.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Very poorly drained; very high surface runoff; low saturated hydraulic conductivity. Endosaturation is present with an apparent seasonal high water table between 15 and 60 cm (very shallow to moderately deep free water occurrence classes) between February and July. Cumulative annual duration class is Common. A drained phase has an apparent seasonal high water table between 122 and 150 cm (deep free water occurrence class) between February and July. These soils are susceptible to occasional flooding for very long periods between February and July. The drained phase is susceptible to rare flooding for very brief periods between year-round.

USE AND VEGETATION: Irrigated pasture and hayland, rangeland, and wildlife habitat. The present vegetation is mainly creeping wildrye, basin wildrye, and rushes.

DISTRIBUTION AND EXTENT: Northern Nevada. These soils are moderately extensive. MLRA 24, 25.

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

SERIES ESTABLISHED: Humboldt County (East Part), Nevada, 1993.

REMARKS: This revision of September 2001 updates the taxonomic class from Fine, smectitic, calcareous, mesic Cumulic Endoaquolls.

Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 74 cm (Ap, Ag1, Ag2, and Ag3 horizons).
Aquic conditions - The conditions of endosaturation, reduction, and redoximorphic features between 15 and 150 cm at certain times during normal years (parts of the Ag1, Ag2, Ag3, Bkg, and Cg horizons).
Particle-size control section - The zone from 25 to 100 cm (Ag2 and Ag3 horizons and parts of the Ag1 and Bkg horizons).

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National Cooperative Soil Survey
U.S.A.