LOCATION DEVADA NV+CA OREstablished Series
TAXONOMIC CLASS: Clayey, smectitic, mesic Lithic Argixerolls
TYPICAL PEDON: Devada very cobbly loam--rangeland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 1 inch; grayish brown (10YR 5/2) very cobbly loam, very dark grayish brown (10YR 3/2) moist; massive; soft, very friable, nonsticky and nonplastic; few very fine roots; many very fine interstitial pores; 25 percent gravel and 20 percent cobbles, slightly acid (pH 6.2); abrupt smooth boundary. (1 to 4 inches thick)
A2--1 to 4 inches; grayish brown (10YR 5/2) very cobbly loam, very dark grayish brown (10YR 3/2) moist; moderate coarse subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and common fine roots; many very fine interstitial pores; 25 percent gravel and 20 percent cobbles; slightly acid (pH 6.4); abrupt smooth boundary. (2 to 6 inches thick)
Bt1--4 to 5 inches; brown (10YR 5/3) clay loam, very dark grayish brown (10YR 3/2) moist; moderate fine subangular blocky structure; slightly hard, very friable, very sticky and moderately plastic; few fine roots; very few fine tubular pores; common distinct clay films on faces of peds; neutral (pH 6.8); abrupt smooth boundary. (0 to 12 inches thick)
Bt2--5 to 13 inches; brown (10YR 4/3) gravelly clay, dark brown (10YR 3/3) moist; strong medium and coarse angular blocky structure; hard, firm, very sticky and very plastic; few fine roots; few fine tubular pores; many prominent clay films on faces of peds and lining pores; 15 percent gravel; neutral (pH 6.8); very abrupt irregular boundary. (2 to 10 inches thick)
R--13 inches; rhyolite.
TYPE LOCATION: Douglas County, Nevada; about 2 miles south-southeast of Holbrook Junction on Wild Oat Mountain; approximately 2,000 feet east and 1,000 feet north of the southwest corner of section 20, T. 10 N., R. 22 E; USGS Topaz Lake 7.5 minute topographic quadrangle; 38 degrees 42 minutes 44 seconds north latitude and 119 degrees 32 minutes 30 seconds west longitude, NAD27.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually moist in winter and spring, dry in summer through late fall; Aridic moisture regime that borders on xeric.
Mean annual soil temperature - 47 to 53 degrees F.
Mollic epipedon thickness - 7 to 20 inches; includes all or part of the argillic horizon.
Depth to base of argillic horizon - 12 to 20 inches.
Depth to bedrock - 12 to 20 inches to a lithic contact.
Particle-size control section - Clay content: 40 to 60 percent; Rock fragments: 0 to 30 percent, mainly gravel. Lithology of fragments are volcanic rocks such as rhyolite, andesite, or basalt.
Other features - Some pedons have thin E or E/B horizons.
A horizons - Value: 4 or 5 dry, 2 or 3 moist. Some pedons have a thin surface layer with value of 6 dry, but when the upper 7 inches are mixed, value is less than 5.5 dry.
Chroma: 2 or 3, dry or moist.
Reaction: Slightly acid through slightly alkaline.
Organic matter content: 1 to 3 percent.
Bt horizons - Hue: 5YR through 10YR.
Value: 4 through 6 dry, 3 or 4 moist.
Chroma: 2 through 4, dry or moist.
Texture: Clay or gravelly clay, commonly with thin subhorizons of clay loam.
Structure: Prismatic, angular blocky, subangular blocky.
Consistence: Slightly hard to very hard, dry; moderately sticky to very sticky, wet.
Reaction: Neutral or slightly alkaline.
Organic matter content: 0.5 to 2 percent.
Other features: Some pedons have thin silica coats on peds and rock fragments in the lower part of the Bt horizon.
COMPETING SERIES: These are the Bidrim, Brezniak, Cullius, Deven, Devnot, Dunnlake, and Wylo series.
Bidrim soils have A horizons with 3 to 8 percent organic matter. Brezniak soils are 7 to 12 inches deep to bedrock. Cullius soils have 10 to 30 percent volcanic glass in the A horizon and do not have abrupt boundaries between the A and Bt horizons. Deven and Devnot soils have a xeric moisture regime and do not have abrupt boundaries between the A and Bt horizons. Dunnlake soils do not have abrupt boundaries between the A and Bt horizons. Wylo soils have mean annual soil temperature of 54 to 59 degrees F. and do not have abrupt boundaries between the A and Bt horizons.
GEOGRAPHIC SETTING: Devada soils are on plateaus, mountains, and hills. They typically occur on summit, shoulder, and footslope positions. These soils formed in residuum weathered from volcanic rock with additions of loess and volcanic ash. Slopes are 0 to 50 percent. Elevations range from 4,400 to 7,500 feet. The mean annual precipitation is 10 to 14 inches, the mean annual temperature is 45 to 49 degrees F., and the frost-free period is 60 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cagle, Drit, Duco, Koontz, Nosrac, and Roloc soils. Cagle and Nosrac soils are deep. Drit soils are deep and lack an argillic horizon. Duco, Koontz, and Roloc soils are loamy-skeletal.
DRAINAGE AND PERMEABILITY: Well drained; very high surface runoff; slow permeability (moderately low or moderately high saturated hydraulic conductivity).
USE AND VEGETATION: Devada soils are used for rangeland and wildlife habitat. The vegetation is mainly low sagebrush, bottlebrush squirreltail, Sandberg's bluegrass, and Thurber's needlegrass. Scattered Utah juniper or western juniper occur in some areas in rangeland plant communities.
DISTRIBUTION AND EXTENT: Northwestern Nevada, northeastern California, and southcentral Oregon. These soils are extensive with about 432,000 acres of the series mapped to date. The original series concept is in MLRA 26, the main acreage is in MLRA 23, and other acreage occurs in MLRAs 21, 24, and 25.
MLRA OFFICE RESPONSIBLE: Reno, Nevada.
SERIES ESTABLISHED: Douglas County Area, Nevada, 1981.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 13 inches (A1, A2, Bt1, and Bt2 horizons).
Argillic horizon - The zone from 4 to 13 inches (Bt1 and Bt2 horizons).
Lithic contact - The boundary at 13 inches to underlying hard, unweathered bedrock (R layer).
Particle-size control section - The zone from the soil surface to 13 inches (A1, A2, Bt1, and Bt2 horizons).
ADDITIONAL DATA: Several pedons of Devada have full characterization data by the Soil Survey Laboratory (SSL), Lincoln, NE, as soil survey sample numbers S86NV-013-301 (pedon # 86P0764), S86NV-031-006 (pedon # 86P0908), and S01NV-031-007 (pedon # 02N0109).