LOCATION WALTI NVEstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Aridic Argixerolls
TYPICAL PEDON: Walti gravelly loam--rangeland. (Colors are for dry soil unless otherwise noted.) The soil surface is partially covered with approximately 25 percent stones.
A--0 to 5 inches; brown (10YR 4/3) gravelly loam, very dark grayish brown (10YR 3/2) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common fine and very fine roots; common fine and very fine interstitial pores; 25 percent gravel and 5 percent cobbles; slightly alkaline (pH 7.4); clear smooth boundary. (4 to 10 inches thick)
2Bt1--5 to 9 inches; dark brown (10YR 3/3) clay loam, very dark grayish brown (10YR 3/2) moist; moderate fine and very fine angular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; common medium, fine, and very fine roots; common fine tubular and few fine interstitial pores; common distinct pressure cutans on faces of peds; 5 percent gravel; slightly alkaline (pH 7.6); abrupt smooth boundary. (4 to 7 inches thick)
3Bt2--9 to 17 inches; brown (10YR 5/3) clay, dark brown (10YR 3/3) moist; strong medium angular blocky structure; hard, firm, moderately sticky and moderately plastic; few fine and very fine roots along faces of peds; common fine and very fine tubular pores; common prominent pressure cutans on faces of peds and few faint clay films lining pores; 5 percent gravel; slightly alkaline (pH 7.8); clear smooth boundary. (6 to 14 inches thick)
3Bt3--17 to 22 inches; yellowish brown (10YR 5/4) gravelly clay, dark yellowish brown (10YR 3/4) moist; strong medium and fine angular blocky structure; hard, firm, moderately sticky and moderately plastic; few fine roots along faces of peds; few fine tubular pores; many prominent pressure faces on peds and few faint clay films lining pores; 15 percent gravel and 5 percent cobbles; slightly alkaline (pH 7.8); abrupt wavy boundary. (4 to 8 inches thick)
3R--22 inches; hard rhyolite.
TYPE LOCATION: Eureka County, Nevada; about 35 miles south of Crescent Valley in the Tonkin summit area west of Roberts Mountain; approximately 1,500 feet east and 2,000 feet south of the northwest corner of section 4, T. 23 1/2 N., R. 49 E.; USGS Tonkin Summit 7.5 minute topographic quadrangle; 39 degrees 54 minutes 20 seconds north latitude and 116 degrees 28 minutes 18 seconds west longitude, NAD27.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually moist in winter and spring, dry from late June to mid-October; Aridic moisture regime that borders on xeric.
Mean annual soil temperature - 44 to 46 degrees F.
Mollic epipedon thickness - 7 to 17 inches; commonly includes the upper part of the argillic horizon.
Depth to bedrock - 20 to 30 inches to a lithic contact.
Particle-size control section - Clay content: 40 to 50 percent;
Rock fragments: 5 to 25 percent, mainly gravel. Lithology of fragments are volcanic rocks such as rhyolite, andesite, dacite, and tuff.
Reaction - Neutral or slightly alkaline.
A horizon
Hue: 7.5YR or 10YR.
Value: 4 or 5 dry.
Chroma: 2 or 3, dry or moist.
Bt horizons
Hue: 7.5YR or 10YR.
Value: 4 or 5 dry, 3 or 4 moist. Some pedons are 6 dry in the lower subhorizon above the bedrock.
Chroma: 2 through 4, dry or moist.
Texture: Clay loam or gravelly clay loam with 27 to 35 percent clay and an abrupt lower boundary in the upper subhorizon. Clay or gravelly clay with 50 to 60 percent clay in the lower subhorizons.
Rock fragments: 5 to 25 percent, mostly gravel and cobbles.
Structure: Prismatic or angular blocky; upper subhorizons are subangular blocky in some pedons.
Consistence: Very friable to firm; moderately sticky or very sticky, moderately plastic or very plastic.
COMPETING SERIES: These are the Alyan, Lerrow, and Prunie series.
Alyan soils do not have clay loam texture in the upper part of the argillic horizon with abrupt boundaries between the Bt1 and Bt2 horizons. Lerrow soils are moderately deep to paralithic contacts. Prunie soils are deep to paralithic contacts.
GEOGRAPHIC SETTING: Walti soils are on hills, mountains, and plateaus. They formed in residuum and colluvium derived dominantly from volcanic rocks. Slopes are 4 to 50 percent. Elevations range from 5,800 to 8,500 feet. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 12 to 16 inches, the mean annual temperature is 43 to 45 degrees F., and the frost-free period is 50 to 80 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cleavage, Robson, and Softscrabble soils. Cleavage soils are loamy-skeletal, shallow to lithic contacts, and have mollic epipedons and argillic horizons. Robson soils are clayey-skeletal, shallow to lithic contacts, and have argillic horizons. Softscrabble soils are loamy-skeletal, very deep, and have argillic horizons and thick mollic epipedons.
DRAINAGE AND PERMEABILITY: Well drained; very high surface runoff; very slow permeability (low or moderately low saturated hydraulic conductivity).
USE AND VEGETATION: Walti soils are used for rangeland and wildlife habitat. The present vegetation is mainly low sagebrush, low rabbitbrush, Idaho fescue, Sandberg's bluegrass, and bluebunch wheatgrass.
DISTRIBUTION AND EXTENT: Central and western Nevada. These soils are moderately extensive. MLRAs 24, 28B, and 27.
MLRA OFFICE RESPONSIBLE: Reno, Nevada.
SERIES ESTABLISHED: Eureka County, Nevada, 1983.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 17 inches (A, 2Bt1, and 3Bt2 horizons).
Argillic horizon - The zone from 5 to 22 inches (2Bt1, 3Bt2, and 3Bt3 horizons).
Lithic contact - The boundary at 22 inches to underlying hard bedrock (R layer).
Particle-size control section - The zone from 5 to 22 inches (2Bt1, 3Bt2, and 3Bt3 horizons).