LOCATION AQUINAS                 NV

Established Series
Rev. ELS/WED/JVC/JBF
02/2017

AQUINAS SERIES

The Aquinas series consists of moderately deep, well drained soils that formed in alluvium derived from granodiorite. Aquinas soils are on fan remnants. Slopes are 4 to 15 percent. The mean annual precipitation is about 230 mm and the mean annual temperature is about 9 degrees C.

TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Haploxeralfic Argidurids

TYPICAL PEDON: Aquinas loamy coarse sand--rangeland. (Colors are for dry soil unless otherwise noted.)

A1--0 to 3 cm; pale brown (10YR 6/3) loamy coarse sand, brown (10YR 4/3) moist; single grain; loose, nonsticky and nonplastic; many fine interstitial pores; moderately acid (pH 6.0); abrupt smooth boundary. (0 to 5 cm thick)

A2--3 to 18 cm; brown (10YR 5/3) sandy loam, dark brown (10YR 3/3) moist; massive; slightly hard, very friable, nonsticky and nonplastic; many very fine and common fine roots; many very fine interstitial pores; slightly acid (pH 6.5); abrupt wavy boundary. (3 to 25 cm thick)

Bt1--18 to 43 cm; light yellowish brown (10YR 6/4) sandy clay loam, dark yellowish brown (10YR 4/4) moist; moderate fine and medium subangular blocky structure; very hard, firm, moderately sticky and moderately plastic; few very fine and fine roots; common fine tubular pores; common faint and few distinct clay films on faces of peds; slightly acid (pH 6.5); clear wavy boundary. (20 to 30 cm thick)

Bt2--43 to 74 cm; light brown (7.5YR 6/4) sandy clay loam, brown (7.5YR 4/4) moist; massive; hard, friable, moderately sticky and moderately plastic; few very fine and fine roots; common fine tubular pores; many faint clay films coating and bridging mineral grains; slightly acid (pH 6.5); clear wavy boundary. (25 to 38 cm thick)

Bt3--74 to 86 cm; light brown (7.5YR 6/4) loamy coarse sand, brown (7.5YR 5/4) moist; massive; hard, friable, nonsticky and nonplastic; few very fine roots; many very fine interstitial pores; common faint clay films coating and bridging mineral grains; slightly acid (pH 6.5); abrupt wavy boundary. (8 to 20 cm thick)

2Bt--86 to 94 cm; light brown (7.5YR 6/4) clay, brown (7.5YR 4/4) moist; strong very fine and fine subangular blocky structure; very hard, friable, very sticky and very plastic; few very fine roots; few very fine tubular pores; many faint and few distinct clay films on faces of peds; slightly alkaline (pH 7.5); abrupt wavy boundary. (0 to 13 cm thick)

2Bkqm1--94 to 102 cm; pinkish gray (7.5YR 6/2) cemented material, brown (7.5YR 4/4) moist; extremely hard, extremely firm; strongly cemented by opaline silica; reddish yellow (7.5YR 6/6) coats lining fractures; few very fine roots in fractures; strongly effervescent; moderately alkaline (pH 8.0); abrupt wavy boundary. (0 to 20 cm thick)

2Bkqm2--102 to 117 cm; light brownish gray (10YR 6/2) cemented material; extremely hard, extremely firm; strongly cemented by opaline silica; strongly effervescent; moderately alkaline (pH 8.0); clear wavy boundary. (10 to 25 cm thick)

3BCk--117 to 157 cm; pale brown (10YR 6/3) stratified silt loam, brown (10YR 5/3) moist; strong thin platy structure; very hard, firm, nonsticky and nonplastic; secondary carbonates segregated as very pale brown (10YR 8/3) lenses and masses; strongly effervescent; moderately alkaline (pH 8.0)

TYPE LOCATION: Washoe County, Nevada; about 12 miles northwest of Reno in Lemmon Valley; approximately 500 feet south and 200 feet east of the northwest corner of section 24, T. 21 N., R. 18 E.; USGS Reno NW 7.5 minute topographic quadrangle; latitude 39 degrees 40 minutes 41 seconds N and longitude 119 degrees 55 minutes 18 seconds W; WGS84 Decimal Degrees 39.6780556 latitude, -119.9216667 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: These soils are usually dry in all parts of the moisture control section but are moist in the winter and spring; aridic moisture regime that borders on xeric.
Mean annual soil temperature: 9 to 11 degrees C.
Depth to base of argillic horizon: 76 to 100 cm.
Depth to duripan: 76 to 100 cm.

Particle-size control section - Clay content: 20 to 35 percent.
Rock fragments: 0 to 15 percent.

A horizons
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 2 or 3 dry or moist.
Reaction: Moderately acid or slightly acid.

Bt horizons
Hue: 10YR or 7.5YR.
Value: 5 or 6 dry, 4 or 5 moist.
Chroma: 2 through 4, dry or moist.
Texture: Sandy clay loam or clay loam.
Reaction: Moderately acid or slightly acid, but is slightly alkaline in the lower part of some pedons.

2Bqm and 2Bkqm horizons
Hue: 10YR or 7.5YR.
Value: 6 or 7 dry, 4 or 5 moist.
Chroma: 3 or 4, dry or moist.
Reaction: Slightly alkaline or moderately alkaline.
Other features: 1.6 mm thick discontinuous indurated laminar cap on the surface of the duripan is present in some pedons; Some pedons have carbonate coats lining fractures.

3BCk horizon
Reaction: Slightly alkaline or moderately alkaline.
Other features: It is compact and semi-consolidated in some pedons.

COMPETING SERIES: These are the Boulflat, Cherry Spring, Eastval, Spasprey, Yody and Zaidy series.

Boulflat soils have bedrock at 56 to 100 cm. Cherry Spring soils have dominantly silt loam argillic with a large component of loess high in ash and glass. Eastval soils have a subhorizon with 35 to 50 percent clay in the particle-size control section. Spasprey soils have a Bk horizon above a duripan at a depth of 50 to 75 cm. Yody soils are moderately alkaline and have a calcic horizon above the duripan. Zaidy soils are less than 76 cm to the duripan.

GEOGRAPHIC SETTING: Aquinas soils are on fan remnants. They have formed in a mantle of alluvium derived from granodiorite superimposed over valley-fill materials containing tuff and volcanic ash. Slopes are 4 to 15 percent. Elevations range from 1,375 to 1,680 meters. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 200 to 250 mm, the mean annual temperature is 9 to 10 degrees C., and the frost-free period is 100 to 120 days.

GEOGRAPHICALLY ASSOCIATED SOILS: This is the Greenbrae soil. Greenbrae soils lack a duripan.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; slow permeability; moderately low saturated hydraulic conductivity.

USE AND VEGETATION: Aquinas soils are used for rangeland, recreation, and urban development. The vegetation is principally Wyoming big sagebrush, green ephedra, Anderson's peachbrush, bottlebrush squirreltail, and cheatgrass.

DISTRIBUTION AND EXTENT: Western Nevada. These soils are not extensive with about 7,000 acres of the series mapped to date. MLRA 26.

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

SERIES ESTABLISHED: Washoe County, Nevada, South Part, 1980.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: The zone from the soil surface to 18 cm (A1 and A2 horizons).
Argillic horizon - The zone from 18 to 94 cm (Bt1, Bt2, Bt3 and 2Bt horizons).
Duripan - The zone from 94 to 117 cm (2Bqm and 2Bkqm horizons).
Identifiable secondary carbonates - The zone from 100 to 157 cm (2Bkqm and 3BCk horizons)
Particle-size control section - The zone from 18 to 68 cm (Bt1 horizon and part of the Bt2 horizon).

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National Cooperative Soil Survey
U.S.A.