LOCATION HUMDUN                  NV+ID

Established Series
Rev. CEJ/RLB/JBF
03/2016

HUMDUN SERIES

The Humdun series consist of very deep, well drained soils formed in loess with a moderate component of volcanic ash over alluvium derived from mostly extrusive volcanic rocks. The Humdun soils are on fan piedmont remnants, fan terraces, foothill and mountain side slopes. Slopes are 1 to 50 percent. The mean annual precipitation is about 275 mm and the mean annual temperature is about 7 degrees C.

TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, frigid Durinodic Xeric Haplocambids

TYPICAL PEDON: Humdun silt loam--rangeland (Colors for dry conditions unless otherwise noted).

A--0 to 20 cm; grayish brown (10YR 5/2) silt loam, dark brown (10YR 3/3) moist; moderate fine granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine, common fine, and few coarse roots; common very fine tubular, and common very fine and fine interstitial pores; several fine and medium old root channels; neutral (pH 6.8); clear smooth boundary. (5 to 20 cm thick)

Bw1--20 to 38 cm; light brownish gray (10YR 6/2) silt loam, brown (10YR 4/3) moist; weak fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common very fine, and few fine and medium roots; many very fine tubular and interstitial pores; several fine and medium old root channels; neutral (pH 6.8); clear smooth boundary. (15 to 28 cm thick)

Bw2--38 to 61 cm; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; weak coarse prismatic structure; hard, very friable, slightly sticky and slightly plastic; common very fine, and few medium roots; many very fine tubular pores; several old root channels; neutral (pH 7.0); clear wavy boundary. (13 to 28 cm thick)

Bw3--61 to 76 cm; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; massive; slightly hard, very friable, slightly sticky and slightly plastic; common very fine, and few medium roots; common very fine tubular pores; moderately alkaline (pH 8.2); clear wavy boundary. (0 to 20 cm thick)

Bkq1--76 to 109 cm; pale brown (10YR 6/3) silt loam, with common medium distinct white (10YR 8/1) carbonate segregations, brown (10YR 4/3) moist; massive; soft, very friable, slightly sticky and slightly plastic; common very fine and few fine roots; common very fine tubular pores; 30 percent 1.9 to 2.5 cm very hard, firm, brittle durinodes; slightly effervescent matrix, strongly effervescent in seams; moderately alkaline (pH 8.4); clear smooth boundary. (15 to 33 cm thick)

Bkq2--109 to 152 cm; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; massive; soft, very friable, slightly sticky and slightly plastic; common very fine roots; 70 percent 1.9 to 2.5 cm very hard, firm, brittle durinodes; strongly effervescent; strongly alkaline (pH 8.6)

TYPE LOCATION: Lander County, Nevada; about 1/4 mile west of Barium mill in Mosquito Canyon south of the T Lazy S Ranch; approximately 2,000 feet north and 700 feet east of the apparent southwest corner of section 18, T. 32 N., R. 47 E.; Mount Diablo base line and meridian. USGS Argenta 7.5 minute topographic quadrangle; latitude 40 degrees 38 minutes 42 seconds N and longitude 116 degrees 43 minutes 37 seconds W; WGS84 Decimal Degrees 40.6450000 latitude, -116.7269444 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually dry, moist in some part from late October through early June; aridic bordering on xeric soil moisture regime.
Mean annual soil temperature: 7 to 9 degrees C.
Combined A and Bw horizon thickness and depth to Bkq horizon: 60 to 84 cm.

Particle-size control section - Clay content: 10 to 15 percent.
Rock fragments: Less than 5 percent, when mixed.

A horizon
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 2 or 3.
Reaction: Neutral or slightly alkaline.
Other features: Pedons with dark colored A horizons do not meet the thickness requirement for a mollic epipedon.

Bw horizons
Value: 5 through 7 dry, 4 or 5 moist.
Chroma: 2 through 4.
Texture: Loam, very fine sandy loam, or silt loam.
Structure: Fine to coarse subangular blocky or prismatic or it is massive.
Reaction: Neutral through moderately alkaline.
Other features: Some pedons have up to 20 percent durinodes in the lower Bw horizon.

Bkq horizons - Hue: 7.5YR or 10 YR
Value: 6 or 7 dry, 4 or 5 moist.
Chroma: 2 through 4.
Consistence: Soft slightly hard or hard dry.
Texture: Loam, very fine sandy loam or silt loam.
Reaction: Moderately alkaline or strongly alkaline.
Cementation: 20 to 80 percent durinodes that are hard to extremely hard dry and firm or very firm moist.
Other features: Most pedons have white carbonate segregations. Some pedons have very gravelly loam 2Bkq horizons at some depth between 100 to 150 cm.

COMPETING SERIES: These are the Poorma, Reallis and Silverado series.

Poorma soils have calcareous Bw horizons less than 56 cm thick. Silverado and Reallis soils have Bw horizons less than 50 cm thick underlain by a continuous weakly silica cemented C horizon.

GEOGRAPHIC SETTING: Humdun soils are on fan piedmont remnants, fan terraces, mountains and foothill side slopes. These soils formed in loess with a moderate component of volcanic ash over alluvium derived mostly extrusive volcanic rocks such as andesite and tuff or alluvium derived from mixed rocks. Elevations are 1,460 to 1,830 meters. Slopes are 1 to 50 percent. The climate is cool and semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 200 to 300 mm; mean annual temperature is 6 to 7 degrees C; and the frost-free season is 70 to 100 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Havingdon, Boulflat and Susie Creek soils. Havingdon soils have clayey-skeletal argillic horizons. Boulflat soils have fine-loamy argillic horizons and indurated duripans. Susie Creek soils have fine textured argillic horizons.

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

USE AND VEGETATION: Rangeland and wildlife habitat. The present vegetation is mainly big sagebrush, Sandberg bluegrass, cheatgrass, bluebunch wheatgrass, bottlebrush squirreltail, Thurber's needlegrass and littleleaf horsebrush.

DISTRIBUTION AND EXTENT: North Central Nevada. Humdun soils are moderately extensive. MLRA 24, 25.

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

SERIES ESTABLISHED: Lander County, Tuscarora Mountain Area, Nevada, 1979.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 18 cm (part of the A horizon)
Xeric Intergrades - Meets organic carbon requirement for xeric.
Cambic horizon - The zone from 20 to 76 cm. (Bw1, Bw2, and Bw3 horizons)
Duric horizon - The zone from 76 to 152 cm. (Bkq1 and Bkq2 horizons)
Particle-size control section - The zone from 25 to 100 cm. (Bw2 and Bw3 horizons and a portion of the Bw1 and Bkq1 horizons)

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National Cooperative Soil Survey
U.S.A.