LOCATION WRENZA                  NV

Established Series
Rev. BKP/JBF
12/2019

WRENZA SERIES

Wrenza series consist of moderately deep, well drained soils that formed in colluvium or glacial moraine deposits derived from metamorphic rock over metamorphic bedrock. Wrenza soils are on upper mountain sideslopes. Slopes are 30 to 75 percent. The mean annual precipitation is about 660 mm and the mean annual temperature is about 4 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, mixed, subactive Xeric Humicryepts

TYPICAL PEDON: Wrenza extremely gravelly sandy loam--rangeland. The surface is covered with about 15 percent metamorphic rock. (Colors are for dry soil unless otherwise noted.)

A1--0 to 10 cm; brown (10YR 4/3) extremely gravelly sandy loam, very dark brown (10YR 2/2) moist; weak coarse subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; 65 percent gravel; slightly acid (pH 6.4); clear smooth boundary. (5 to 10 cm thick)

A2--10 to 30 cm; brown (10YR 5/3) very gravelly fine sandy loam, very dark brown (10YR 2/2) moist; weak coarse subangular blocky structure; soft, very friable, nonsticky and nonplastic; 35 percent gravel; moderately acid (pH 5.6); clear smooth boundary. (20 to 65 cm thick)

AB--30 to 85 cm; brown (10YR 5/3) very gravelly very fine sandy loam, very dark brown (10YR 2/2) moist; moderate medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; 33 percent gravel and 5 percent cobbles; moderately acid (pH 6.0); abrupt irregular boundary. (50 to 75 cm thick)

R--85 cm; indurated slightly fractured metamorphic rock.

TYPE LOCATION: Elko County, Nevada; on the Humboldt National Forest east of Elko below Secret Peak; about 2,000 feet north and feet west of the southeast corner of section 6, T. 33 N., R. 60 E.; USGS Secret Valley 7.5 minute topographic quadrangle; latitude 40 degrees 46 minutes 5.29 seconds N and longitude 115 degrees 14 minutes 23.46 seconds W; WGS84 Decimal Degrees 40.7681361 latitude, -115.23985 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually moist in winter and spring, dry September and October; additional moisture is supplied by run on from steep upper slopes and lateral water movement in lower control section or substratum; typic xeric soil moisture regime.
Mean annual soil temperature: 4 to 7 degrees C.
Mean summer soil temperature: 6 to 8 degrees C.
Base saturation: 10 to 50 percent; lowest base saturation readings are generally in the middle of the profile.
Umbric epipedon thickness: 40 to 100 cm.
Reaction: Moderately acid to slightly acid.
Depth to a lithic contact: averages 50 to 100 cm.

Particle-size control section - Clay content: 10 to 18 percent.
Rock fragments: Averages 35 to 60 percent, mainly gravel with 0 to 10 percent cobbles or stones usually occurring below 50 cm.

A1 horizon
Chroma: 2 or 3 dry and 1 or 2 moist.
Organic matter content: 2 to 3 percent.

A2 horizon
Value: 4 or 5 dry.
Chroma: 2 or 3 dry and 1 or 2 moist.
Organic matter content: 1 to 2 percent.

AB horizon (Bw when present)
Value: 4 or 5 dry.
Chroma: 3 or 2 dry, 4 dry in Bw horizons.
Structure: Weak or moderate, subangular blocky or granular.
Organic matter content: 1 to 2 percent.
Texture: Very gravelly fine sandy loam or very gravelly sandy loam, with some thin sub horizons ranging up to extremely gravelly.
Reaction: Slightly acid to moderately acid.

COMPETING SERIES: Inpendence soils are very deep, average greater than 3 percent organic matter throughout A horizons, and have reactions that average very strongly acid through moderately acid in the umbric epipedon.

GEOGRAPHIC SETTING: Wrenza soils are on upper mountains flanks. They typically occur on upper backslope positions. These soils formed in colluvium derived from metamorphic parent material. Slopes are 30 to 75 percent. Elevations range from 2,400 to 3,000 meters. The climate is subhumid with cold, moist winters and cool, dry summers. The mean annual precipitation is 610 to 710 mm derived mostly from snow with additional moisture as run-on from steep upper slopes. The mean annual temperature is 4 to 6 degrees C and the frost-free period is 50 to 80 days. Frost may occur in any month at the higher elevations.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Inpendence, Hackwood, and Hapgood soils. Inpendence soils are very deep, average greater than 3 percent organic matter throughout A horizons, and have reactions that average very strongly acid through moderately acid in the umbric epipedon. Hackwood soils are very deep, have clay content averaging greater than 18 percent and rock fragments averaging less than 35 percent in the particle size control section. Hapgood soils are deep and average greater than 18 percent clay in the particle size control section. Hackwood and Hapgood soils have a base saturation that averages greater than 50 percent in some or all parts.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; high surface runoff; high saturated hydraulic conductivity.

USE AND VEGETATION: Wrenza soils are used for rangeland and wildlife habitat. The vegetation is principally service berry, snowberry, and chokecherry with an under story of mountain brome and forbs.

DISTRIBUTION AND EXTENT: Northeastern Nevada. MLRA 25.

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

SERIES ESTABLISHED: Elko County, Nevada, Humboldt National Forest, Nevada, North Part, 2016.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Umbric epipedon - The zone from the soil surface to 85 cm (A1, A2, and AB horizons).
Lithic contact - The boundary at 85 cm (R layer).
Particle-size control section - The zone from 25 to 85 cm (lower part of A2 horizon and AB horizon).

---

National Cooperative Soil Survey
U.S.A.