LOCATION POLUM                   NV

Established Series
Rev. TEB/GJS/JBF
02/2023

POLUM SERIES

The Polum series consists of very deep, well drained soils that formed in residuum and colluvium derived from limestone, dolomite, and calcareous shale. Polum soils are on side slopes of mountains. Slopes are 30 to 75 percent. The mean annual precipitation is about 360 and the mean annual temperature is about 6 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Pachic Calcicryolls

TYPICAL PEDON: Polum gravelly silt loam--rangeland. (Colors are for dry soil unless otherwise noted.) The soil surface is partially covered with approximately 20 percent gravel.

A1--0 to 3 cm; dark grayish brown (10YR 4/2) gravelly silt loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine roots; common very fine tubular pores; 25 percent gravel; slightly effervescent; moderately alkaline (pH 8.0); clear smooth boundary. (3 to 18 cm thick)

A2--3 to 18 cm; dark grayish brown (10YR 4/2) gravelly silt loam, very dark grayish brown (10YR 3/2) moist; weak thin platy structure; soft, very friable, slightly sticky and slightly plastic; many very fine and few fine and medium roots; few very fine tubular pores; 25 percent gravel; slightly effervescent; moderately alkaline (pH 8.0); clear smooth boundary. (10 to 25 cm thick)

A3--18 to 43 cm; dark grayish brown (10YR 4/2) very gravelly loam, very dark grayish brown (10YR 3/2) moist; massive; soft, very friable, slightly sticky and slightly plastic; many very fine and few fine roots; common very fine tubular pores; 40 percent gravel; slightly effervescent; moderately alkaline (pH 8.0); clear smooth boundary. (0 to 25 cm thick)

Bk1--43 to 61 cm; light brownish gray (10YR 6/2) very gravelly loam, dark grayish brown (10YR 4/2) moist; massive; slightly hard, very friable; slightly sticky and slightly plastic; common very fine and few fine and medium roots; common very fine tubular pores; 40 percent gravel; violently effervescent, common fine and medium carbonate filaments; thin carbonate coats on gravel, moderately alkaline (pH 8.4); clear smooth boundary. (18 to 46 thick)

Bk2--61 to 152; light brownish gray (10YR 6/2) very gravelly loam, dark grayish brown (10YR 4/2) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; common very fine and few fine tubular pores; 55 percent gravel; strongly effervescent, common fine carbonate filaments, thin carbonate coats on gravel; moderately alkaline (pH 8.2).

TYPE LOCATION: Pershing County, Nevada; near Star Peak, approximately 10 miles south of Imlay, about 100 feet north and 1,700 feet west of the southeast corner of section 29, T. 31 N., R. 34 E.; USGS Star Peak 7.5 minute topographic quadrangle; latitude 40 degrees 31 minutes 22 seconds N and longitude 118 degrees 09 minutes 49 seconds W; WGS84 Decimal Degrees 40.5230556 latitude, -118.1805556 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Moist late fall through early summer, dry late July through September. Typic xeric moisture regime.
Mean annual soil temperature: 5 to 7 degrees C.
Average summer soil temperature: 12 to 15 degrees C.
Mollic epipedon thickness: 40 to 76 cm, may include the upper part of the Bk horizons in some pedons.
Depth to bedrock: Greater than 150 cm.
Calcium carbonate equivalent: 15 to 35 percent.

Particle-size control section - Clay content: 12 to 18 percent.
Rock fragments: 40 to 60 percent, mainly gravel.

A horizon
Value: 4 or 5 dry.
Chroma: 2 or 3.

Bk horizon
Value: 5 or 6 dry, 3 or 4 moist. Darker value is in the upper subhorizon.
Chroma: 2 through 4.
Texture: Very gravelly loam or very gravelly silt loam.

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

GEOGRAPHIC SETTING: Polum soils are on side slopes of mountains. These soils formed in residuum and colluvium derived from limestone, dolomite, sandstone, chert and calcareous shale. Slopes are 30 to 75 percent. Elevations are 2,290 to 2,750 meters. The climate is cool, semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 360to 410 mm mean annual temperature is 4 to 7 degrees C, and the frost-free season is 50 to 80 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the tentative DeSoot and Hummer series. DeSoot and Hummer soils have mollic epipedons less than 16 inches thick. DeSoot soils also have a carbonate equivalent of 40 to 60 percent and Hummer soils are moderately deep to bedrock.

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

USE AND VEGETATION: Rangeland and wildlife habitat. The present vegetation is mainly mountain big sagebrush, mountain brome, slender wheatgrass, and snowberry.

DISTRIBUTION AND EXTENT: North-central Nevada. The soil is not extensive.

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

SERIES ESTABLISHED: Pershing County, Nevada, East Part. 1986.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface is 43 cm (A1, A2, A3 horizons).
Calcic horizon - The zone from 43 to 61 cm (Bk1 horizon).
Particle-size control section - The zone from 25 to 100 cm (Bk1 and part of the A3 and Bk2 horizons).

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National Cooperative Soil Survey
U.S.A.