LOCATION ALYAN                   NV+OR

Established Series
Rev. TSB-RLB-JVC-JBF
02/2016

ALYAN SERIES

The Alyan series consists of moderately deep, well drained soils that formed in residuum and colluvium derived from volcanic rocks. Alyan soils are on hills, mountains, and plateaus. Slopes are 2 to 50 percent. The mean annual precipitation is about 250 mm and the mean annual temperature is about 7 degrees C.

TAXONOMIC CLASS: Fine, smectitic, frigid Aridic Argixerolls

TYPICAL PEDON: Alyan gravelly clay loam--rangeland. (Colors are for dry soil unless otherwise noted.)

A1--0 to 5 cm; grayish brown (10YR 5/2) gravelly clay loam, very dark grayish brown (10YR 3/2) moist; weak fine through coarse subangular blocky structure; soft, very friable, moderately sticky and moderately plastic; many very fine and fine, few medium roots; many very fine tubular and irregular pores; 25 percent gravel; neutral (pH 7.0); abrupt smooth boundary. (2 to 13 cm thick)

A2--5 to 23 cm; dark grayish brown (10YR 4/2) gravelly clay loam, very dark brown (10YR 2/2) moist; weak medium subangular blocky structure; soft, very friable, moderately sticky and moderately plastic; few very fine and fine roots; many very fine, few fine and medium tubular pores; 25 percent gravel; neutral (pH 7.2); clear wavy boundary. (8 to 30 cm thick)

Bt1--23 to 41 cm; brown (10YR 5/3) clay, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; hard, firm, very sticky and very plastic; few very fine and fine roots; many very fine through medium tubular pores; common distinct clay films bridging sand grains and coating fragments; 10 percent gravel; neutral (pH 7.2); clear wavy boundary. (8 to 20 cm thick)

Bt2--41 to 71 cm; yellowish brown (10YR 5/4) gravelly clay, dark yellowish brown (10YR 4/4) moist; moderate medium and coarse subangular blocky structure; very hard, firm, very sticky and very plastic; few very fine and fine roots; common very fine through medium tubular pores; common distinct clay films on faces of peds, lining pores, bridging sand grains, and coating fragments; 30 percent gravel; neutral (pH 7.2); clear wavy boundary. (10 to 46 cm thick)

Bt3--71 to 81 cm; light yellowish brown (10YR 6/4) very gravelly clay, yellowish brown (10YR 5/4) moist; massive; very hard, firm, very sticky and very plastic; few very fine roots; common very fine and fine tubular pores; common prominent clay films bridging sand grains and coating fragments; 40 percent gravel; neutral (pH 7.2); abrupt wavy boundary. (0 to 13 cm thick)

R--81 cm; siliceous tuff.

TYPE LOCATION: Elko County, Nevada; about 1 mile east-southeast of Midas; 10 feet upslope of a mining road approximately 600 feet west and 1,200 feet north of the southeast corner of section 21, T. 39 N., R. 46 E.; USGS Midas 7.5 minute topographic quadrangle; latitude 41 degrees 14 minutes 18 seconds N and longitude 116 degrees 46 minutes 47 seconds W; WGS84 Decimal Degrees 41.2383333 latitude, -116.7797222 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually moist in winter and spring, dry from mid-June to mid-October; aridic soil moisture regime that borders on xeric.
Mean annual soil temperature: 7 to 8 degrees C.
Mollic epipedon thickness: 20 to 48 cm; includes the Bt1 horizon in some pedons.
Depth to base of argillic horizon: 50 to 100 cm.
Depth to bedrock: 50 to 100 cm to a lithic contact.

Particle-size control section - Clay content: Averages 35 to 55 percent.
Rock fragments: Averages 15 to 35 percent, mainly gravel. Lithology of fragments are volcanic rocks such as tuff.

A horizons
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Organic matter content: 1 to 3 percent.
Reaction: Neutral or slightly alkaline.

Bt1 horizon
Hue: 10YR or 7.5YR.
Value: 5 or 6 dry, 3 through 5 moist.
Chroma: 2 through 4, dry or moist.
Texture: Clay or gravelly clay, cobbly clay, clay loam, or cobbly clay loam.
Clay content: 27 to 55 percent.
Organic matter content: 0.5 to 2 percent.

Bt2 and Bt3 horizons
Hue: 10YR or 7.5YR.
Value: 5 through 7 dry, 4 or 5 moist.
Chroma: 3 or 4, dry or moist.
Texture: Clay, clay loam, gravelly clay, gravelly clay loam, cobbly clay loam, or cobbly clay; thin subhorizons of very gravelly clay overlying the bedrock are common in some pedons.
Clay content: 35 to 55 percent.
Structure: Subangular blocky, subangular blocky parting to angular blocky, or is massive.
Consistence: Friable or firm, moist; moderately sticky or very sticky and moderately plastic or very plastic, wet.
Reaction: Neutral or slightly alkaline.

COMPETING SERIES: These are the Prunie, and Walti series.

Prunie soils are deep to paralithic contacts. Walti soils have an abrupt boundary between the Bt1 and Bt2 horizons and have prismatic or angular blocky structure in at least one subhorizon of the argillic horizon.

GEOGRAPHIC SETTING: Alyan soils are on hills, mountains, and plateaus. They occur on all slope positions. These soils formed in residuum and colluvium derived from volcanic rocks. Slopes are 2 to 50 percent. Elevations range from 1,525 to 2,290 meters in Nevada to as low as 1,280 meters in Oregon. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 250 to 360 mm, mean annual temperature is 6 to 7 degrees C, and the frost-free period is typically 70 to 100 days, but may range down to 50 days in Oregon.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bregar, Cotant, Graley, Millerlux, and Ninemile soils.

Bregar soils are loamy-skeletal, shallow to lithic contacts, and have ochric epipedons. Cotant soils are shallow to paralithic contacts. Graley soils are clayey-skeletal and shallow to lithic contacts. Millerlux soils are shallow to lithic contacts and have ochric epipedons. Ninemile soils are shallow to lithic contacts.

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

USE AND VEGETATION: Alyan soils are used for rangeland and wildlife habitat. The vegetation is mainly mountain big sagebrush, bluebunch wheatgrass, Thurber's needlegrass, and Sandberg's bluegrass.

DISTRIBUTION AND EXTENT: Northern Nevada and south-central Oregon. These soils are moderately extensive. The series concept and main acreage is in MLRA 25, while other acreage occurs in MLRA 24 in Nevada and MLRA 23 in Oregon.

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

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

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 41 cm (A1, A2, and Bt1 horizons).
Argillic horizon - The zone from 23 to 81 cm (Bt1, Bt2, and Bt3 horizons).
Lithic contact - The boundary at 81 cm to underlying hard, unweathered bedrock (R layer).
Particle-size control section - The zone from 23 to 73 cm (Bt1 and Bt2 horizons and part of the Bt3 horizon).

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National Cooperative Soil Survey
U.S.A.