LOCATION ATRYPA                  NV

Established Series
Rev. WMA/RAF/GJS
11/2016

ATRYPA SERIES

The Atrypa series consists of shallow, well drained soils that formed in residuum derived from shale, with a minor component of colluvial materials from limestone, dolomite, and conglomerate rocks. Atrypa soils are on foothills and mountain sideslopes. Slopes are 5 to 75 percent. The mean annual precipitation is about 330 mm and the mean annual temperature is about 7 degrees C.

TAXONOMIC CLASS: Loamy, mixed, superactive, frigid, shallow Calcidic Haploxerolls

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

A1--0 to 5 cm; grayish brown (10YR 5/2) loam, dark brown (10YR 3/3) moist; moderate fine granular structure; soft, very friable, slightly sticky and slightly plastic; common fine and very fine roots; few fine, and common very fine tubular pores; neutral (pH 6.6); clear smooth boundary. (0 to 15 cm thick)

A2--5 to 18 cm; grayish brown (10YR 5/2) loam, dark brown (10YR 3/3) moist; moderate fine granular structure; soft, very friable, moderately sticky and slightly plastic; many fine and very fine roots; few fine, and common very fine tubular pores; neutral (pH 7.0); gradual smooth boundary. (13 to 23 cm thick)

Bk1--18 to 25 cm; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; massive; slightly hard, very friable, slightly sticky and slightly plastic; many fine and very fine roots; few fine, and common very fine tubular pores; slightly effervescent; moderately alkaline (pH 8.0); clear wavy boundary. (0 to 41 cm thick)

Bk2--25 to 33 cm; light brownish gray (10YR 6/2) loam, dark grayish brown (10YR 4/2) moist; massive; slightly hard, very friable, slightly sticky and slightly plastic; few fine, and common very fine roots; common very fine tubular pores; strongly effervescent; strongly alkaline (pH 8.6); abrupt wavy boundary. (5 to 20 cm thick)

Cr--33 to 76 cm; shale bedrock carbonate-coated seams and fractures. This shale has a hardness of less than 3 and is highly fractured.

TYPE LOCATION: Eureka County, Nevada; approximately 25 miles north of Eureka on Garden Pass Summit; about 2,350 feet north and 2,400 feet west of the southeast corner of section 31, T. 23 N., R. 52 E.; USGS Garden Pass 7.5 minute topographic quadrangle; latitude 39 degrees 49 minutes 45 seconds N and longitude 116 degrees 9 minutes 21 seconds W; WGS84 Decimal Degrees 39.8291667 latitude, -116.1558333 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually dry; moist in winter and spring, dry July through October; aridic moisture regime bordering on xeric.
Mean annual soil temperature: 6 to 8 degrees C.
Mollic epipedon thickness: 18 to 30 cm.
Depth to paralithic contact: 25 to 50 cm.

Particle-size control section - Clay: 18 to 27 percent.
Rock fragments: 5 to 35 percent mainly gravel.

A horizon
Value: 5 or 6 dry; (averages less than 5.5 when the upper 18 cm is mixed). 3 or 4 moist; (averages less than 3.5 when the upper 18 cm is mixed).
Chroma: 2 or 3.
Structure: Weak to strong, fine and medium granular or subangular blocky; weak medium or thick platy.
Reaction: Neutral through moderately alkaline.
Effervescence: Noneffervescent or slightly effervescent.

Bk horizon
Value: 5 to 7 dry, 3 to 6 moist.
Chroma: 1 to 3.
Texture: Loam or gravelly loam.
Structure: Weak subangular blocky or it is massive.
Reaction: Slightly alkaline through strongly alkaline
Effervescence: Slightly effervescent or strongly effervescent, usually increasing with depth.
Carbonates: Less than 15 percent calcium carbonate equivalent.

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

GEOGRAPHIC SETTING: Atrypa soils are on foothill and mountain side slopes. These soils formed in residuum and colluvium derived from shale, with a minor component of colluvial materials from limestone, dolomite, and conglomerate rock. Slopes are 5 to 75 percent. Elevations are 1,950 to 2,380 meters. The climate is cool, semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 300 to 360 mm, mean annual temperature is 6 to 7 degrees C, and the frost-free season is 50 to 90 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bartine, Fusulina, Labshaft, Locane, Mau, and Sheege. Bartine soils are cryic and have carbonatic minerology. Fusulina and Labshaft soils are cryic, and in addition Labshaft soils are shallow over a lithic contact. Locane soils are shallow over a lithic contact and have an argillic horizon. Mau soils have a clayey-skeletal argillic horizon. Sheege soils are cryic and have carbonatic mineralogy.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; medium or rapid runoff; moderately high saturated hydraulic conductivity.

USE AND VEGETATION: Woodland, livestock grazing, and wildlife habitat. The present vegetation is mainly singleleaf pinyon and Utah juniper with an understory of mountain big sagebrush, bottlebrush squirreltail and Sandberg's bluegrass.

DISTRIBUTION AND EXTENT: North-central and northeastern Nevada. These soils are not extensive. MLRA 28B

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

SERIES ESTABLISHED: Eureka County (Diamond Valley Area), Nevada, l971.

REMARKS: Diagnostic horizons and features recognized in this pedon:
Mollic epipedon - The zone from the soil surface to 25 cm (A1, A2, and Bk1 horizons).
Paralithic contact - The boundary at 33 cm (Cr layer).
Particle-size control section - The zone from the soil surface to 33 cm ( A1, A2, Bk1, and Bk2 horizons).

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National Cooperative Soil Survey
U.S.A.