LOCATION WILPAR NVInactive Series
TAXONOMIC CLASS: Clayey-skeletal, smectitic, frigid Typic Argixerolls
TYPICAL PEDON: Wilpar very stony sandy loam--forestland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 2 inches; grayish brown (10YR 5/2) very stony sandy loam, very dark grayish brown (10YR 3/2) moist; weak medium subangular blocky structure; soft, very friable, slightly sticky and nonplastic; few very fine roots; many very fine and fine interstitial pores; neutral (pH 6.8); abrupt smooth boundary. (1 to 3 inches thick)
2A2--2 to 5 inches; dark grayish brown (10YR 4/2) gravelly sandy loam, very dark brown (10YR 2/2) moist; moderate very fine granular structure; soft, very friable, slightly sticky and slightly plastic; common very fine and fine roots; common very fine and fine interstitial pores; neutral (pH 6.8); clear wavy boundary. (2 to 8 inches thick)
2Bt1--5 to 10 inches; brown (7.5YR 4/3) very gravelly sandy clay, dark brown (10YR 3/3) moist; moderate medium and fine subangular blocky structure; slightly hard, very friable, very sticky and very plastic; many very fine, common fine, and few medium roots; common very fine interstitial and few very fine tubular pores; common distinct clay bridges on sand grains; 40 percent pebbles; neutral (pH 6.8); clear wavy boundary. (3 to 8 inches thick)
2Bt2--10 to 16 inches; brown (7.5YR 5/4) very gravelly clay, brown (7.5YR 4/4) moist; weak medium and coarse subangular blocky structure; hard, friable, very sticky, very plastic; many very fine, and few fine and medium roots; many very fine and fine interstitial, and few very fine tubular pores; common prominent clay films lining pores; 40 percent pebbles and some cobbles; neutral (pH 6.8); clear wavy boundary. (5 to 10 inches thick)
2Bt3--16 to 26 inches; light brown (7.5YR 6/4) extremely gravelly clay, brown (7.5YR 5/4) moist; massive; very hard, friable, very sticky and very plastic; many very fine, few fine, and few medium roots; many very fine interstitial and few very fine and fine tubular pores; many prominent brown (7.5YR 5/4) clay films lining pores; 70 percent pebbles and some cobbles; neutral (pH 6.8); abrupt wavy boundary. (8 to 12 inches thick)
2Bt4--26 to 43 inches; pale brown (10YR 6/3) extremely gravelly sandy clay, brown (7.5YR 5/4) moist; massive; very hard, friable, very sticky and very plastic; many very fine, few fine, and few medium roots; many very fine interstitial and few very fine and fine tubular pores; common distinct strong brown (7.5YR 5/6) clay bridges on sand grains; 75 percent pebbles and some paragravel; neutral (pH 7.2); abrupt wavy boundary. (10 to 20 inches thick)
2Bt5--43 to 58 inches; light yellowish brown (10YR 6/4) extremely gravelly sandy clay loam, brown (7.5YR 5/4) moist; massive; hard, friable, moderately sticky and moderately plastic; few very fine and few fine roots; many very fine and fine tubular pores; common distinct and few prominent clay bridges on sand grains; 75 percent pebbles and some paragravel; neutral (pH 7.3); gradual wavy boundary. (10 to 20 inches thick)
2Crt--58 to 60 inches; white (10YR 8/1) and light gray (10YR 7/2) highly weathered tuff (ignimbrite), light gray (10YR 7/1) and very pale brown (10YR 7/3) moist; rock structure; few medium roots in fractures; bedrock crushes to very gravelly sandy clay loam with common faint yellowish brown (10YR 5/6) clay films coating pebbles.
TYPE LOCATION: Lincoln County, Nevada; 1,300 feet north and 1,700 feet east of the south quarter corner of section 8, T. 5 N., R. 68 E.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually moist in the moisture control section during winter and spring, dry during summer and fall and dry in all parts for 45 consecutive days following the summer solstice; intermittently moist in horizons above the moisture control section for 10 to 20 cumulative between July and September following summer convection storms; Xeric moisture regime that borders on aridic.
Mean annual soil temperature - 44 to 47 degrees F.
Mean summer soil temperature - 59 to 61 degrees F.
Mollic epipedon thickness - 10 to 15 inches, includes the Bt1 horizon.
Depth to base of argillic horizon - 52 to 60 inches.
Depth to bedrock - 52 to 60 inches to a paralithic contact. The paralithic materials below the contact are weathered volcanic rocks such as rhyodacitic tuff.
Particle-size control section - Clay content: 35 to 50 percent; Rock fragments: Averages 50 to 60 percent, mainly pebbles. Lithology of fragments are volcanic rocks such as rhyodacitic tuff.
Reaction - Slightly acid to slightly alkaline (pH 6.4 to 7.6) becoming more alkaline with depth.
A horizons - Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Structure: Weak or moderate, very fine to medium subangular blocky or granular structure.
Organic matter content: 1 to 3 percent.
2Bt1 and 2Bt2 horizons - Hue: 7.5YR or 10YR.
Value: 4 through 6 dry, 4 or 5 moist.
Chroma: 3 through 6, dry or moist.
Texture: Very gravelly clay and very gravelly sandy clay.
Clay content: 35 to 50 percent.
Rock fragments: 40 to 50 percent, mainly pebbles.
Consistence: Hard or very hard dry, friable or firm moist.
2Bt3 and 2Bt4 horizons - Hue: 7.5YR or 10YR.
Value: 4 through 6 dry, 4 or 5 moist.
Chroma: 3 through 6, dry or moist.
Texture: Very gravelly clay, extremely gravelly sandy clay, or extremely gravelly clay.
Clay content: 35 to 50 percent.
Rock fragments: 50 to 75 percent, mainly pebbles.
Structure: Weak or moderate, fine to coarse subangular blocky structure, or massive.
Consistence: Hard or very hard dry, friable or firm moist.
2Bt5 horizon - Clay content: 20 to 35 percent.
Rock fragments: 60 to 75 percent.
Pararock fragments: Some pedons have minor amounts of highly weathered tuff paragravel.
COMPETING SERIES: These are the Birchcreek, Derringer, Droem (T), Erakatak, Leevan, McIvey, Ravenswood, Roostercomb, Sharesnout, Swanpeak (T), Threek, Tickville (T), Urwil, Yago, and Yeates Hollow series.
Birchcreek, Droem, Leevan, Ravenswood, Roostercomb, Sharesnout, and Tickville soils are moderately deep to lithic contacts. Derringer and Erakatak soils are moderately deep to paralithic contacts. McIvey, Swanpeak, Threek, Urwil, and Yago soils are very deep. Yeates Hollow soils are deep to lithic contacts.
GEOGRAPHIC SETTING: Wilpar soils are on mountains. They typically occur on backslope positions. These soils formed mainly in residuum, with minor amounts of colluvium, weathered from rhyodacitic tuff. Rock outcrops occur in complex with these soils. Slopes are 30 to 50 percent. Elevations range from 6,800 to 7,800 feet. The climate is semiarid with cold, moist winters and cool, dry summers. The mean annual precipitation is 14 to 16 inches with most of it coming as snow. The mean annual temperature is 42 to 43 degrees F. and the frost-free period is about 80 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Hamtah, Homestake, Tica, Udel, Winu, and Winz soils. Hamtah soils have thick mollic epipedons. Homestake soils are very deep, have weakly silica and carbonate cemented horizons, and have frigid temperature regime. Tica soils are shallow to lithic contacts. Udel soils are very shallow to lithic contacts and do not have argillic horizons. Winu soils are fine-loamy, moderately deep to lithic contacts, and have thick mollic epipedons. Winz soils are very deep and have ochric epipedons and albic horizons above argillic horizons.
DRAINAGE AND PERMEABILITY: Well drained; very high surface runoff; slow permeability.
USE AND VEGETATION: Wilpar soils are used mainly for wildlife habitat, but provide some livestock grazing. The vegetation is a forest canopy of singleleaf pinyon with a sparse understory of mountain big sagebrush and associated grasses and forbs. Some Utah juniper, curlleaf mountainmahogany, and serviceberry are also present.
DISTRIBUTION AND EXTENT: East-central Nevada. These soils are not extensive with about 5,300 acres of the series mapped to date. MLRA 29.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.
SERIES ESTABLISHED: Lincoln County (Meadow Valley Area), Nevada, 1971.
REMARKS: This revision of March 2001 updates the taxonomic class from Clayey-skeletal, smectitic Argic Cryoborolls.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 10 inches (A1, 2A2, and 2Bt1 horizons).
Argillic horizon - The zone from 5 to 58 inches (2Bt1, 2Bt2, 2Bt3, 2Bt4, and 2Bt5 horizons).
Paralithic contact - The boundary at 58 inches to underlying soft, weathered bedrock (2Crt layer).
Particle-size control section - The zone from 5 to 25 inches (2Bt1 and 2Bt2 horizons and part of the 2Bt3 horizon).