LOCATION COLVAL                  NV

Established Series
Rev. JWM/TM/JBF
11/2016

COLVAL SERIES

The Colval series consists of very deep, well drained soils that formed in alluvium derived mainly from welded tuff and limestone over lacustrine deposits derived mainly from welded tuff and limestone. Colval soils are on basin floors. Slopes range from 0 to 2 percent. The mean annual precipitation is about 175 mm and the mean annual temperature is about 13 degrees C.

TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Durinodic Calciargids

TYPICAL PEDON: Colval silt loam--rangeland. (Colors are for dry soil unless otherwise noted.) The surface is covered with approximately 20 percent cyanobacteria and 10 percent lichens.

A--0 to 13 cm; very pale brown (10YR 8/3) silt loam, yellowish brown (10YR 5/4) moist; strong coarse subangular blocky structure parting to moderate thick platy; slightly hard, friable, very sticky and moderately plastic; few very fine, fine and medium roots; common fine and medium vesicular pores; 18 percent calcium carbonate equivalent; violently effervescent; moderately alkaline (pH 8.2); clear smooth boundary. (5 to 13 cm thick)

Btk--13 to 28 cm; very pale brown (10YR 7/4) silty clay loam, yellowish brown (10YR 5/4) moist; strong medium subangular blocky structure parting to moderate thin platy; hard, firm, very sticky and moderately plastic; common very fine and few fine and medium roots; common fine interstitial and tubular pores; common faint clay films on faces of peds; secondary calcium carbonate is finely disseminated; 23 percent calcium carbonate equivalent; violently effervescent; very strongly alkaline (pH 9.1); clear smooth boundary. (12 to 50 cm thick)

Btkq--28 to 58 cm; very pale brown (10YR 7/4) silty clay loam, yellowish brown (10YR 5/4) moist; strong medium subangular blocky structure parting to moderate thick platy; hard, firm, moderately sticky and slightly plastic; few very fine, fine and medium roots; few fine tubular pores; 30 percent durinodes 2 to 8 millimeters in diameter; secondary calcium carbonate is finely disseminated; 25 percent calcium carbonate equivalent; violently effervescent; strongly alkaline (pH 8.6); clear smooth boundary. (15 to 38 cm thick)

2Bk1--58 to 91 cm; very pale brown (10YR 8/2) silt loam, light brownish gray (10YR 6/2) moist; moderate fine and medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; few very fine and fine roots; common fine tubular pores; secondary calcium carbonate is finely disseminated; 27 percent calcium carbonate equivalent; strongly effervescent; strongly alkaline (pH 8.7); gradual diffuse boundary. (25 to 64 cm thick)

2Bk2--91 to 152 cm; very pale brown (10YR 8/2) sandy clay loam, light brownish gray (10YR 6/2) moist; moderate fine and medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; few very fine and fine roots; few fine tubular pores; secondary calcium carbonate is finely disseminated; 32 percent calcium carbonate equivalen; violently effervescent; strongly alkaline (pH 8.7).

TYPE LOCATION:: Lincoln County, Nevada; approximately 1.5 miles east of Murphy Gap Reservoir and 50 feet south of dirt road; about 1,860 feet south and 810 feet east of the northwest corner of section 17, T. 1 S., R. 60 E.; USGS Murphy Gap SE 7.5 minute topographic quadrangle; latitude 37 degrees 51 minutes 45 seconds N and longitude 115 degrees 16 minutes 45 seconds W; WGS84 Decimal Degrees 37.8625000 latitude, -115.2791667 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually dry; moist in winter and spring and for 10 to 20 days cumulative from July through September due to summer convection storms; typic aridic soil moisture regime.
Mean annual soil temperature: 14 to 15 degrees C.
Depth to argillic horizon: 5 to 13 cm.
Thickness of the argillic horizon: 25 to 65 cm.
Depth to calcic horizon: 5 to 13 cm.

Particle-size control section: Clay content: 27 to 35 percent.

A horizon
Hue: 10YR or 2.5Y
Value: 6 through 8 dry, 4 through 7 moist.
Chroma: 1 through 4, dry or moist.

Btk horizon
Hue: 10YR or 2.5Y
Value: 6 or 7 dry, 4 through 6 moist.
Chroma: 2 through 4, dry or moist.
Textures: Silty clay loam, silt loam, or clay loam.
Clay content: 20 to 35 percent.
Calcium carbonate equivalent: 20 to 30 percent in the material less than 2 mm.
Effervescence: Slightly effervescent to violently effervescent.
Reaction: Moderately alkaline to very strongly alkaline.

Btkq horizon
Hue: 10YR or 2.5Y
Value: 6 or 7 dry, 5 or 6 moist.
Chroma: 2 through 4, dry or moist.
Clay content: 27 to 35 percent.
Calcium carbonate equivalent: 25 to 40 percent in the material less than 2 mm.
Durinodes: 15 to 60 percent.
Effervescence: Strongly effervescent to violently effervescent.
Reaction: Moderately alkaline to very strongly alkaline.

2Bk and 2Bkq (when present) horizons
Hue: 10YR or 2.5Y
Value: 6 through 8 dry, 4 through 6 moist.
Chroma: 1 through 3, dry or moist.
Textures: Silty clay loam, sandy clay loam or silt loam.
Clay content: 25 to 35 percent.
Calcium carbonate equivalent: 20 to 35 percent in the material less than 2 mm.
Durinodes (when present): 30 to 80 percent.
Effervescence: Strongly effervescent to violently effervescent.
Reaction: Strongly alkaline or very strongly alkaline.

COMPETING SERIES: At present, there are no competing series.

GEOGRAPHIC SETTING: Colval soils are on basin floors. These soils formed in alluvium derived mainly from welded tuff and limestone over lacustrine deposits derived mainly from welded tuff and limestone. Slopes range from 0 to 2 percent. Elevation ranges from 1,375 to 1,740 meters. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation ranges from 125 to 200 mm, the mean annual temperature ranges from 13 to 14 degrees C, and the frost free period ranges from 120 to 160 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Slaw and Penoyer series. Slaw and Penoyer soils do not have calcic horizons, argillic horizons, or durinodes.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; negligible or low runoff; moderately low saturated hydraulic conductivity.

USE AND VEGETATION: Colval soils are used for livestock grazing and wildlife habitat. The potential native vegetation includes Bonneville saltbush, shadscale, green-molly kochia, and winterfat. This pedon is correlated to Ecological Site R029XY159NV, Deep Silty 5-8 P.Z.

DISTRIBUTION AND EXTENT: Eastern Nevada. These soils are not extensive. MLRA 29.

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

SERIES ESTABLISHED: Lincoln County, Nevada, North Part, 2005. The name is coined from Coal Valley, where it originated.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: The zone from the soil surface to 13 cm (A horizon).
Argillic horizon: The zone from 13 to 58 cm (Btk and Btkq horizons).
Calcic horizon: The zone from 13 to 152 cm (Btk, Btkq, 2Bk1 and 2Bk2 horizons).
Durinodes: The zone from 28 to 58 cm (Btkq horizon).
Particle-size control section: The zone from 13 to 58 cm (Btk and Btkq horizons).

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National Cooperative Soil Survey
U.S.A.