LOCATION BULLUMP NV+CA OR UTEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Pachic Argixerolls
TYPICAL PEDON: Bullump gravelly loam--rangeland. (Colors are for dry soil unless otherwise noted.) The surface is partially covered by 20 percent pebbles and 5 percent cobbles.
A1--0 to 3 inches; brown (10YR 4/3) gravelly loam, very dark grayish brown (10YR 3/2) moist; weak fine subangular blocky structure; soft, very friable, slightly sticky and nonplastic; many very fine and fine roots; many very fine and common fine tubular pores; 20 percent pebbles; neutral (pH 7.2); clear wavy boundary. (2 to 8 inches thick)
A2--3 to 9 inches; brown (10YR 4/3) gravelly loam, very dark grayish brown (10YR 3/2) moist; moderate medium subangular blocky structure; soft, very friable, slightly sticky and nonplastic; many very fine and common fine roots; many very fine and common fine tubular pores; 20 percent pebbles; neutral (pH 7.3); clear wavy boundary. (3 to 12 inches thick)
BA--9 to 23 inches; brown (10YR 5/3) very gravelly loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and fine roots; many very fine and common fine tubular pores; 35 percent pebbles; neutral (pH 7.3); gradual wavy boundary. (0 to 20 inches thick)
Bt1--23 to 32 inches; pale brown (10YR 6/3) very gravelly loam, brown (10YR 4/3) moist; moderate medium subangular blocky structure; slightly hard, very friable, moderately sticky and moderately plastic; common very fine and common fine roots; common very fine and common fine tubular pores; common faint clay films on faces of peds; 35 percent pebbles and 5 percent cobbles; neutral (pH 7.3); clear wavy boundary. (7 to 17 inches thick)
Bt2--32 to 54 inches; light yellowish brown (10YR 6/4) very gravelly clay loam, brown (10YR 4/3) moist; moderate fine subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; common fine and few very fine roots; common very fine and fine tubular pores; many distinct clay films on faces of peds and lining pores; 40 percent pebbles and 15 percent cobbles; neutral (pH 7.2); abrupt wavy boundary. (8 to 30 inches thick)
R--54 inches; hard fractured quartzite; few fine, few coarse, and common medium roots lining fractures in the bedrock.
TYPE LOCATION: Elko County, Nevada; in the Elko Hills about 2 miles southwest of Ryndon; approximately 220 feet south and 500 feet west of the northeast corner of section 24, T. 35 N., R. 56 E.; USGS Ryndon 7.5 minute topographic quadrangle; 40 degrees 54 minutes 43 seconds north latitude and 115 degrees 36 minutes 21 seconds west longitude, NAD27.
RANGE IN CHARACTERISTICS:
Soil moisture - Moist in winter and early summer, dry late July to early October. Additional soil moisture may be supplied by lateral water movement in the lower part of the profile; Xeric moisture regime that borders on aridic.
Mean annual soil temperature - 43 to 47 degrees F.
Mollic epipedon thickness - 20 to 40 inches; includes the transitional BA horizon when present and may include the Bt1 horizon in some pedons.
Depth to base of argillic horizon - 40 to 60 inches.
Depth to bedrock - 40 to 80 inches to a lithic contact.
Particle-size control section - Clay content: 25 to 35 percent;
Rock fragments: 35 to 55 percent, mainly pebbles. Lithology of fragments are mixed rocks.
Reaction - Slightly acid through slightly alkaline.
Other features - Some very deep pedons have C horizons below 40 inches.
A horizons
Value: 3 through 5 dry, 2 or 3 moist.
Chroma: 1 through 3, dry or moist.
Organic matter content: 2 to 7 percent.
Bt horizons
Hue: 7.5YR or 10YR.
Value: 4 through 6 dry, 2 through 4 moist.
Chroma: 2 through 6, dry or moist.
Texture: Very gravelly loam, very gravelly clay loam, or very gravelly sandy clay loam.
Clay content: 25 to 35 percent.
Rock fragments: 35 to 55 percent.
Organic matter content: 0.5 to 3 percent.
Structure: Fine through coarse subangular blocky or angular blocky.
Consistence: Slightly sticky or moderately sticky and slightly plastic or moderately plastic.
Other features: Uncoated sand grains and few silt coats lining pores occur in some pedons. Some pedons have few distinct relict redox concentrations of iron or manganese stains on pebbles.
COMPETING SERIES: These are the Bullvaro, Burchflat, Camelback, Chrisflat, Demner (T), Dogbed, Dooh (T), Erig, Krenka, Leroman, Lockgate, Murain, Nutval (T), Snyderville, Softback, Softscrabble, Staberg, Vetagrande, and Vipont series.
Bullvaro and Nutval soils have an aridic moisture regime and 18 to 25 percent clay in the particle-size control section. Burchflat and Vipont soils are moderately deep to lithic contacts. Camelback and Softback soils have 60 to 80 percent rock fragments in the particle-size control section and are dominated by cobbles. Chrisflat and Murain soils do not have lithic contacts between 40 and 80 inches from the soil surface. Demner and Snyderville soils have depth to base of the argillic horizon of less than 40 inches and have sandy C horizons. Dooh soils have an aridic moisture regime. Dogbed soils have mollic epipedons that include most subhorizons of the argillic horizon and have rock fragments which are volcanic rocks such as tuff, tuff-breccia, and andesite. Erig soils are dominated by cobbles in the particle-size control section. Krenka soils have 20 to 25 percent clay in the particle-size control section. Leroman and Staberg soils are moderately deep to paralithic contacts. Lockgate soils are deep to paralithic contacts. Softscrabble soils are dominated by cobbles in the particle-size control section and have depth to base of the argillic horizon of more than 60 inches. Vetagrande soils have an aridic moisture regime and average 18 to 27 percent clay in the particle-size control section.
GEOGRAPHIC SETTING: Bullump soils are on mountains. They typically occur on backslope positions. These soils formed in colluvium derived from quartzite, argillite, chert, conglomerate, shale, and rhyolite with a component of loess. Slopes are 5 to 75 percent. Elevations range from 4,800 to 8,600 feet. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is typically 14 to 18 inches, but ranges to 22 inches at the highest elevations. The mean annual temperature is 41 to 46 degrees F. and the frost-free period is 50 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cleavage, Hapgood, Inpendence, and Tusel soils. Cleavage soils are shallow to bedrock. Hapgood, Inpendence, and Tusel soils have a cryic temperature regime.
DRAINAGE AND PERMEABILITY: Well drained; high or very high surface runoff; moderately slow permeability (moderately low or moderately high saturated hydraulic conductivity).
USE AND VEGETATION: Bullump soils are used for livestock grazing and wildlife habitat. The present vegetation is mainly mountain big sagebrush, antelope bitterbrush, snowberry, mountain brome, Idaho fescue, and bluebunch wheatgrass.
DISTRIBUTION AND EXTENT: Northern Nevada, northeastern California, southern Oregon, and western Utah. These soils are extensive with about 102,000 acres of the series mapped to date. MLRAs 21, 23, 25, and 28A.
MLRA OFFICE RESPONSIBLE: Reno, Nevada.
SERIES ESTABLISHED: Elko County (Central Part), Nevada, 1986.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 23 inches (A1, A2, and BA horizons).
Argillic horizon - The zone from 23 to 54 inches (Bt1 and Bt2 horizons).
Lithic contact - The boundary at 54 inches to underlying hard bedrock (R layer).
Particle-size control section - The zone from 23 to 43 inches (Bt1 horizon and part of the Bt2 horizon).