LOCATION HAMTAH NV+UTEstablished Series
TAXONOMIC CLASS: Clayey-skeletal, smectitic, frigid Vitrandic Argixerolls
TYPICAL PEDON: Hamtah very stony ashy sandy clay loam--rangeland. (Colors are for dry soil unless otherwise noted.) The soil surface is covered by approximately 20 percent pebbles, 10 percent cobbles and 10 percent stones. Lithology of the fragments is welded tuff.
A1--0 to 10 inches; dark grayish brown (10YR 4/2) very stony ashy sandy clay loam, very dark brown (10YR 2/2) moist; moderate fine and medium granular structure; soft, very friable, moderately sticky and moderately plastic; many very fine, and few fine, medium, and coarse roots; many very fine interstitial pores; 20 percent pebbles, 10 percent cobbles and 10 percent stones; slightly acid (pH 6.5); gradual smooth boundary. (6 to 12 inches thick)
A2--10 to 21 inches; dark grayish brown (10YR 4/2) gravelly ashy sandy clay loam, very dark brown (10YR 2/2) moist; moderate fine and medium subangular blocky structure; slightly hard, very friable, moderately sticky and moderately plastic; many very fine, and few fine, medium, and coarse roots; many very fine interstitial, and many very fine, and few fine tubular pores; 25 percent pebbles and 5 percent cobbles; neutral (pH 6.6); gradual smooth boundary. (6 to 14 inches thick)
Bt1--21 to 33 inches; brown (7.5YR 5/2) gravelly ashy clay loam, brown (7.5YR 4/2) moist; moderate medium subangular blocky structure; hard, friable, moderately sticky and moderately plastic; many very fine, and few fine and medium roots; many very fine interstitial and tubular pores; many distinct clay films lining pores, on faces of peds and as bridges between sand grains; 30 percent pebbles; neutral (pH 6.8); gradual smooth boundary. (9 to 15 inches thick)
Bt2--33 to 41 inches; pinkish gray (7.5YR 6/2) very gravelly ashy clay loam, brown (7.5YR 4/2) moist; strong coarse subangular blocky structure parting to moderate medium subangular blocky; hard, friable, very sticky and very plastic; common very fine roots; many very fine interstitial and tubular pores; many distinct clay films lining pores, on faces of peds and as bridges between sand grains; 50 percent pebbles and 5 percent cobbles; neutral (pH 6.6); clear smooth boundary. (8 to 15 inches thick)
Bt3--41 to 60 inches; variegated brown (7.5YR 5/4), strong brown (7.5YR 5/6), and white (10YR 8/1) gravelly ashy clay loam, dark brown (7.5YR 3/3), brown (7.5YR 5/2), and white (10YR 8/1) moist; strong coarse subangular blocky structure parting to moderate fine and very fine angular blocky; hard, firm, moderately sticky and moderately plastic; few very fine and fine roots; few very fine tubular pores; many distinct clay films along fracture planes of pararock fragments; 30 percent gravel, 20 percent paragravel and 5 percent paracobbles; neutral (pH 7.0).
TYPE LOCATION: Lincoln County, Nevada; about 7 miles west of Meadow Valley Wash at the Confidence Mine; approximately 900 feet west and 1,300 feet north of the southeast corner of section 17, T. 3 N., R. 71 E.; USGS Rice Mountain 7.5 minute topographic quadrangle; 38 degrees 6 minutes 54 seconds north latitude and 114 degrees 3 minutes 8 seconds west longitude, NAD 27.
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 some part of the moisture control section for 10 to 20 days cumulative between July and September following summer convection storms. Typic xeric soil moisture regime.
Mean annual soil temperature - 42 to 45 degrees F.
Mean summer soil temperature - 60 to 62 degrees F.
Mollic epipedon thickness - 20 to 26 inches.
Depth to base of argillic horizon - Greater than 60 inches.
Mineralogy: 20 to 50 percent volcanic glass and glass aggregates in the .02 to 2 millimeter fraction in the upper part, decreasing with depth.
Control section - Clay content: 35 to 50 percent.
Rock fragments: 35 to 50 percent, mainly pebbles and cobbles. Lithology of fragments is volcanic rocks such as welded tuff.
A horizons - Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 1 or 2, dry or moist.
Organic matter content: 2 to 6 percent.
Bt1 and Bt2 horizons - Hue: 7.5YR or 10YR.
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 2 through 4, dry or moist.
Texture: Ashy clay loam or clay.
Clay content: 35 to 50 percent.
Structure: Subangular blocky or prismatic.
Bt3 horizon - Hue: 5YR through 10YR.
Value: 5 through 8 dry, and 3 through 8 moist.
Chroma: 1 through 6, dry or moist.
Clay content: 27 to 35 percent.
Rock fragments: 15 to 35 percent, mainly gravel. 10 to 40 percent paragravel and paracobbles are present in most pedons.
Other features: This horizon has up to 50 percent discontinuous areas of the original rock structure visible as pararock fragments that part readily to weak or moderate fine and medium angular or subangular blocky structure. Its lower boundary is diffuse and grades gradually to hard bedrock.
COMPETING SERIES: These are the
Breeseranch,
Dupratt,
Erakatak,
Finsel and
Menbo series.
Breeseranch soils are 40 to 60 inches deep to a lithic contact and have an O horizon.
The Dupratt soils are 20 to 40 inches deep to a lithic contact and contain 50 to 60 percent clay in the particle-size control section.
Erakatak soils are 20 to 40 inches deep to a lithic contact and the mollic epipedon is 8 to 19 inches thick.
Finsel and Menbo soils are 20 to 40 inches deep to a lithic contact
GEOGRAPHIC SETTING: Hamtah soils are on hills and mountains. These soils formed in colluvium and residuum derived from welded tuff and undifferentiated volcanic rocks such as rhyodacitic tuff and welded tuff. Slopes are 4 to 50 percent. Elevations range from 6,200 to 8,500 feet. The climate is semiarid with cold, moist winters and cool, dry summers. The mean annual precipitation is 16 to 20 inches, most of which comes as snow. The mean annual temperature is 40 to 43 degrees F. and the frost-free period is 40 to 70 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Nevtah, Tica, Udel, Wilpar, Winu, and Winz soils. Nevtah soils are loamy-skeletal, moderately deep to lithic contacts, have thick mollic epipedons, and do not have argillic horizons. Tica soils are shallow to lithic contacts. Udel soils are loamy-skeletal, very shallow to lithic contacts, and do not have argillic horizons. Wilpar soils are deep to paralithic contacts and have a frigid temperature regime. Winu soils are fine-loamy, moderately deep to lithic contacts,. Winz soils have ochric epipedons and albic horizons.
DRAINAGE AND PERMEABILITY: Well drained; high or very high surface runoff; slow permeability.
USE AND VEGETATION: Hamtah soils are used for wildlife habitat and livestock grazing. The vegetation is mainly mountain big sagebrush, Utah serviceberry, antelope bitterbrush, and snowberry with scattered singleleaf pinyon and curlleaf mountainmahogany . Grasses present are bluebunch wheatgrass, basin wildrye, bottlebrush squirreltail, and Thurber's needlegrass.
DISTRIBUTION AND EXTENT: East-central Nevada and west-central Utah. These soils are moderately extensive. The series concept and main acreage is in MLRA 28A, while other acreage occurs in MLRA 47 in Utah.
MLRA OFFICE RESPONSIBLE: Reno, Nevada.
SERIES ESTABLISHED: Lincoln County (Meadow Valley Area), Nevada, 1971.
REMARKS: Author and reviewer initials were shorted to the most recent. Other reviewer initials were: LNL-LR-ELS.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon- the zone from the soil surface to 21 inches (A1 and A2 horizons).
Argillic horizon - The zone from 21 to 60 inches (Bt1, Bt2, and BC horizons).
Vitrandic feature: The zone from the soil surface to 41 inches (A1, A2, Bt1, and Bt2 horizons).
Particle-size control section - The zone from 21 to 41 inches (Bt1 and Bt2 horizons).