LOCATION VALCREST NVEstablished Series
TAXONOMIC CLASS: Clayey over loamy, smectitic over mixed, superactive, mesic Xeric Natrargids
TYPICAL PEDON: Valcrest loam--rangeland. (Colors are for dry soil unless otherwise noted.)
Al--0 to 3 inches; light brownish gray (10YR 6/2) loam, dark brown (10YR 3/3) moist; strong very thin platy structure; soft, very friable, slightly sticky and slightly plastic; common fine and very fine roots; common very fine vesicular pores; slightly effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (2 to 4 inches thick)
A2--3 to 7 inches; pale brown (10YR 6/3) loam, brown (10YR 4/3) moist; moderate very thin platy structure; slightly hard, very friable, moderately sticky and slightly plastic; many fine and very fine roots; common very fine tubular pores; 5 percent pebbles; slightly effervescent; moderately alkaline (pH 8.4); abrupt wavy boundary. (3 to 5 inches thick)
A3--7 to 10 inches; pale brown (10YR 6/3) clay loam, brown (10YR 4/3) moist; weak thin and medium platy structure; slightly hard, very friable, moderately sticky and moderately plastic; few medium, many very fine and fine roots; few fine and many very fine tubular pores; 5 percent pebbles; slightly effervescent; moderately alkaline (pH 8.4); abrupt wavy boundary. (2 to 4 inches thick)
Btnk1--10 to 18 inches; light yellowish brown (10YR 6/4) clay, brown (7.5YR 4/4) moist; strong medium prismatic structure parting to strong medium angular blocky; hard, friable, very sticky and very plastic; common fine and very fine roots; many very fine tubular pores; common faint and distinct clay films on faces of peds and lining pores; strongly effervescent; secondary carbonates segregated in common fine filaments; strongly alkaline (pH 8.8); clear wavy boundary. (7 to 9 inches thick)
Btnk2--18 to 22 inches; light yellowish brown (10YR 6/4) clay, brown (7.5YR 4/4) moist; moderate medium prismatic structure parting to moderate fine angular blocky; hard, friable, very sticky and very plastic; few fine and very fine roots; common very fine tubular pores; many distinct clay films on faces of peds and lining pores; violently effervescent; secondary carbonates segregated in many fine filaments; 5 percent pebbles; strongly alkaline (pH 9.0); clear wavy boundary. (4 to 6 inches thick)
Btnk3--22 to 29 inches; very pale brown (10YR 7/3) clay loam, yellowish brown (10YR 5/4) moist; weak coarse and medium prismatic structure; hard, very friable, moderately sticky and moderately plastic; few fine and very fine roots; common very fine tubular pores; common faint clay films on faces of peds and lining pores; 10 percent pebbles; violently effervescent; secondary carbonates segregated in many fine filaments; very strongly alkaline (pH 9.2); abrupt wavy boundary. (6 to 8 inches thick)
2Bk--29 to 60 inches; light gray (10YR 7/2) sandy loam, yellowish brown (10YR 5/4) moist; massive; soft, very friable, slightly sticky and slightly plastic; few medium, common fine and very fine roots; common very fine tubular pores; 10 percent pebbles; violently effervescent; secondary carbonates segregated in few fine filaments; very strongly alkaline (pH 9.2).
TYPE LOCATION: Eureka County, Nevada; in Pine Valley about 14 miles south and 14 miles east of the community of Crescent Valley; approximately 1,600 feet north and 530 feet east of the southwest corner of section l5, T. 27 N., R. 50 E.; USGS Curlow Flat 7.5 minute topographic quadrangle; 40 degrees 13 minutes 09 seconds north latitude and 116 degrees 19 minutes 40 seconds west longitude, NAD27.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually moist in winter and spring, dry mid-June through October; Aridic moisture regime that borders on xeric.
Mean annual soil temperature - 47 to 52 degrees F.
Depth to base of natric horizon - 24 to 35 inches.
Depth to strongly contrasting materials - 24 to 35 inches.
Particle-size control section - Clay content: 35 to 50 percent in the upper part and 12 to 20 percent in the contrasting lower part; Rock fragments: 0 to 15 percent in the upper part and 5 to 15 percent in the contrasting lower part. Lithology of fragments are mixed igneous rocks such as andesite, rhyolite, and granite.
A horizons - Value: 3 or 4 moist.
Chroma: 2 or 3, dry or moist.
Btnk horizons - Value: 6 or 7 dry, 4 or 5 moist.
Chroma: 3 or 4, dry or moist.
Texture: Clay loam or clay.
Clay content: 35 to 50 percent.
Rock fragments: 0 to 15 percent pebbles.
Salinity (EC): 2 to 4 mmhos/cm.
Sodicity (SAR): 13 to 45.
Reaction: Strongly alkaline or very strongly alkaline (up to pH 9.6).
Calcium carbonate equivalent: 3 to 5 percent.
2Bk horizon - Texture: Sandy loam or gravelly sandy loam.
Clay content: 12 to 20 percent.
Rock fragments: 5 to 15 percent pebbles; some pedons may have subhorizons with up to 30 percent pebbles.
Salinity (EC): 2 to 16 mmhos/cm.
Sodicity (SAR): 13 to 45.
Reaction: Very strongly alkaline (up to pH 11.0).
Calcium carbonate equivalent: 3 to 5 percent.
COMPETING SERIES: There are currently no other series in this family.
GEOGRAPHIC SETTING: Valcrest soils are on fan remnants. They typically occur on summit positions. These soils formed in alluvium derived from mixed igneous rocks with a component of loess. Slopes are 2 to 8 percent. Elevations range from 5,200 to 6,000 feet. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 8 to 10 inches, the mean annual temperature is 46 to 49 degrees F., and the frost-free period is 100 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Fortank, Pineval, Tomera, and Tulase soils. Fortank soils are fine, moderately deep to paralithic contacts, and have argillic horizons. Pineval soils are loamy-skeletal, have argillic horizons, and have horizons with firm consistence and a brittle manner of failure. Tomera soils are fine and have horizons in the substratum with more than 35 percent rock fragments. Tulase soils are coarse-silty and have horizons with durinodes.
DRAINAGE AND PERMEABILITY: Well drained; very high surface runoff; slow permeability.
USE AND VEGETATION: Valcrest soils are used for rangeland and wildlife habitat. The vegetation is mainly Wyoming big sagebrush, bottlebrush squirreltail, Sandberg's bluegrass, and rabbitbrush.
DISTRIBUTION AND EXTENT: Central Nevada. These soils are not extensive with about 7,400 acres of the series mapped to date. MLRA 24.
MLRA OFFICE RESPONSIBLE: Reno, Nevada.
SERIES ESTABLISHED: Eureka County Area, Nevada, 1983.
REMARKS: This revision of February 2004 updates the taxonomic class from Fine, smectitic, mesic Xeric Natrargids.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 10 inches (A1, A2, and A3 horizons).
Natric horizon - The zone from 10 to 29 inches (Btnk1, Btnk2, Btnk3 horizons).
Major lithologic discontinuity - The abrupt change to loamy material at 29 inches (2Bk horizon).
Identifiable secondary carbonates - The zone from 10 to 60 inches (Btnk1, Btnk2, Btnk3, and 2Bk horizons).
Particle-size control section - The zone from 10 to 29 inches (Btnk1, Btnk2, and Btnk3 horizons).