LOCATION JUMBO NV+CA

Established Series
Rev. OWB/WED/JBF
03/2017

JUMBO SERIES

The Jumbo series consists of deep, well drained soils that formed in colluvium and residuum from volcanic rock. Jumbo soils are on hills and mountains. Slopes are 30 to 70 percent. The mean annual precipitation is about 500 mm and the mean annual temperature is about 7 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Pachic Ultic Argixerolls

TYPICAL PEDON: Jumbo very stony loam--rangeland. (Colors are for dry soil unless otherwise noted.)

A1--0 to 13 cm; dark grayish brown (10YR 4/2) very stony loam, very dark grayish brown (10YR 3/2) moist; strong very fine granular structure; soft, very friable, nonsticky and nonplastic; common fine and very fine roots; many fine and very fine interstitial, and common fine tubular pores; 15 percent gravel, 10 percent cobbles, and 10 percent stones; slightly acid (pH 6.4); clear smooth boundary. (10 to 15 cm thick)

A2--13 to 28 cm; dark grayish brown (10YR 4/2) gravelly loam, very dark grayish brown (10YR 3/2) moist; strong fine granular structure; soft, very friable, nonsticky and slightly plastic; many fine and very fine, common coarse and medium roots; many very fine and fine interstitial and tubular pores; 20 percent gravel and 5 percent cobbles; slightly acid (pH 6.4); clear wavy boundary. (13 to 20 cm thick)

A3--28 to 53 cm; grayish brown (10YR 5/2) cobbly loam, dark brown (7.5YR 3/2) moist; moderate medium angular blocky structure; soft, very friable, slightly sticky and slightly plastic; many fine and very fine, common medium and coarse roots; many fine and very fine interstitial and tubular pores; 5 percent gravel, l5 percent cobbles, and 5 percent stones; slightly acid (pH 6.4); clear smooth boundary. (25 to 30 cm thick)

Bt1--53 to 86 cm; brown (10YR 4/3) very cobbly loam, brown (7.5YR 4/2) moist; massive; soft, very friable, slightly sticky and slightly plastic; common fine through coarse roots; common fine and medium tubular pores; few faint clay bridges between sand grains; 5 percent gravel, 40 percent cobbles, and l percent stones; slightly acid (pH 6.4); gradual wavy boundary. (25 to 38 cm thick)

Bt2--86 to 137 cm; brown (10YR 4/3) very cobbly clay loam, brown (10YR 4/3) moist; massive; soft, very friable, slightly sticky and slightly plastic; common fine through coarse roots; common fine and medium tubular pores; common faint clay films bridging sand grains and in pores; 5 percent gravel, 40 percent cobbles, 1 percent stones; slightly acid (pH 6.4); gradual irregular boundary. (20 to 56 cm thick)

Cr--137 cm; highly weathered volcanic bedrock.

TYPE LOCATION: Washoe County, Nevada; about 8 miles south-southwest of Reno; about 1,000 feet south and 50 feet east of the northwest corner of sec. 27, T. 18 N., R. 19 E.; USGS Mount Rose NE 7.5 minute topographic quadrangle; latitude 39 degrees 0 minutes 31 seconds N and longitude 114 degrees 17 minutes 55 seconds W; WGS84 Decimal Degrees 39.3994444 latitude, -119.8450000 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually moist but are dry for 90 to 110 consecutive days during the summer and fall.
Xeric moisture regime.
Mean annual soil temperature: 7 to 8 degrees C.
Mollic epipedon: 50 to 76 cm thick.
Depth to the base of the argillic horizon: 50 to 100 cm.
Depth to a paralithic: 100 to 150 cm.

Particle-size control section - Clay content: 20 to 30 percent.
Rock fragments: 40 to 65 percent, mostly cobbles and gravel but usually includes a few stones.

A horizons
Hue: 10YR or 7.5YR.
Value: 4 or 5 dry, 2 or 3 moist.
Structure: Usually granular or subangular blocky but angular blocky structure in the lower part in some pedons.
Reaction: Medium acid to neutral.

Bt horizons
Hue: l0YR or 7.5YR.
Value of 4 through 6 dry, 4 or 5 moist.
Chroma: 2 or 3.
Texture: Loam or clay loam.
Modifiers: Very gravelly or very cobbly.
Structure: Usually massive, but angular blocky or prismatic in some pedons.

COMPETING SERIES: These are the Smarts and Toncana series.

Toncana soils have hue of 5YR or 2.5YR in the B2t horizon. Smarts soils are dry for 60 to 90 days.

GEOGRAPHIC SETTING: Jumbo soils are on mountains. Slopes of 30 to 70 percent. These soils formed in colluvium and residuum derived from tuff. Elevations are 1,830 to 2,290 meters. The climate is cool, continental with cold moist winters and hot dry summer. The mean annual precipitation is 400 to 640 mm. Mean annual temperature is 6 to 7 degrees C. Frost-free season is about 80 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Duckhill and Fraval soils. Duckhill soils lack a mollic epipedon and have a lithic contact within 50 cm. Fraval soils have a mollic epipedon 18 to 30 cm thick and a paralithic contact within 100 cm.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; rapid runoff; moderately rapid permeability; high saturated hydraulic conductivity.

USE AND VEGETATION: Jumbo soils are used primarily for wildlife habitat, watershed, and limited timber harvesting. The vegetation is principally Ponderosa pine or mountain mahogany. Big sagebrush, bitterbrush, gooseberry, squirreltail, cheatgrass, and bluegrasses are in burned or harvested areas.

DISTRIBUTION AND EXTENT: Western Nevada along the eastern front of the Sierra Nevada Mountains, and northeastern part of the Carson Range. These soils are of small extent. MLRA 22.

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

SERIES ESTABLISHED: Washoe County (South Part), Nevada, l980.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 53 cm (A1, A2 and A3 horizons).
Argillic horizon - The zone from 53 to 137 cm (Bt1 and Bt2 horizons).
Paralithic contact - The boundary at 137 cm to underlying bedrock (Cr layer).
Particle-size control section - The zone from 53 to 103 cm (Bt1 and part of the Bt2 horizons).

ADDITIONAL DATA: Characterization samples S75 NV-31-9.

National Cooperative Soil Survey
U.S.A.