LOCATION DIAMONDHIL NVEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Ustic Argidurids
TYPICAL PEDON: Diamondhil very cobbly fine sandy loam, rangeland and wildlife habitat. (Colors are for dry soil unless otherwise noted.) The soil surface is covered by approximately 20 percent pebbles, 20 percent cobbles and 2 percent stones.
A--0 to 2 inches; brown (7.5YR 5/4) very cobbly fine sandy loam, brown (7.5YR 4/4) moist; moderate medium platy structure; soft, very friable, nonsticky and nonplastic; few very fine and fine roots; common very fine vesicular pores and few very fine and fine interstitial; 20 percent pebbles, 20 percent cobbles and 2 percent stones; slightly effervescent in irregular patches, noneffervescent matrix; moderately alkaline (pH 8.0); clear smooth boundary. (1 to 3 inches thick)
Btk1--2 to 10 inches; reddish brown (5YR 4/4) very cobbly sandy clay loam, yellowish red (5YR 4/6) moist; moderate medium subangular blocky structure; moderately hard, friable, slightly sticky and moderately plastic; common very fine through medium and few coarse roots; common very fine, fine and few medium tubular pores; common faint clay films on ped faces and bridging sand grains; many fine calcium carbonate coats on bottom of rock fragments; 25 percent pebbles, 25 percent cobbles and 5 percent stones; strongly effervescent (5 percent calcium carbonate equivalent in the fine earth fraction); moderately alkaline (pH 8.0); clear wavy boundary. (6 to 12 inches thick)
Btk2--10 to 19 inches; yellowish red (5YR 5/6) extremely cobbly fine sandy loam, yellowish red (5YR 4/6) moist; moderate medium and coarse subangular blocky structure; moderately hard, very friable, slightly sticky and slightly plastic; common very fine and fine, few medium and coarse roots; common very fine, few fine and medium tubular pores; common faint clay films lining pores and on ped faces and bridging sand grains; few fine irregular soft masses of calcium carbonate; many medium calcium carbonate coats on bottom of rock fragments; 30 percent pebbles, 25 percent cobbles and 5 percent stones; violently effervescent (25 percent calcium carbonate equivalent in the fine earth fraction); moderately alkaline (pH 8.2); clear wavy boundary. (7 to 15 inches thick)
Bkq--19 to 31 inches; light brown (7.5YR 6/4) extremely gravelly sandy loam, brown (7.5YR 5/4) moist; massive; slightly hard, very friable, nonsticky and nonplastic; common very fine, few fine and medium roots; common very fine, few fine and medium tubular and interstitial pores; common (10 percent) fine and medium irregular soft masses of calcium carbonate; many fine calcium carbonate coats on bottom of rock fragments; 50 percent pebbles, 15 percent cobbles and 3 percent stones; 25 percent discontinuous moderately cemented layers; violently effervescent (45 percent calcium carbonate equivalent in the fine earth fraction); moderately alkaline (pH 8.4); abrupt wavy boundary. (6 to 14 inches thick)
Bqkm--31 to 60 inches; pinkish white (7.5YR 8/2) and pink (7.5YR 7/3) very strongly cemented duripan with subhorizons that are moderately cemented, pink (7.5YR 7/3) and light brown (7.5YR 6/3) moist; massive; rigid through very hard, rigid through extremely firm; strongly effervescent; strongly alkaline (pH 8.6).
TYPE LOCATION: Clark County, Nevada; approximately 1.75 miles north of Spring Mountain Ranch in Red Rock National Recreation Area; in an un-sectioned area about 2,540 feet north and 400 feet west of the southwest corner of section 26, T. 21 S., R. 58 E.; USGS Blue Diamond, NV 7.5 minute topographic quadrangle; 36 degrees, 05 minutes, 33 seconds north latitude and 115 degrees, 27 minutes, 21 seconds west longitude; UTM 11s, 639014e, 3995311n; NAD 83.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually dry, moist in some part for short periods during winter and early spring and for brief periods between July to October following convection storms. Has an Aridic moisture regime bordering on ustic.
Soil temperature - 53 to 58 degrees F.
Depth to argillic horizon - 1 to 3 inches.
Depth to calcic horizon - 7 to 15 inches.
Depth to base of argillic horizon - 15 to 30 inches.
Depth to duripan - 24 to 40 inches.
Control section - Percent clay: Averages 18 to 27 percent.
Rock fragments: 50 to 70 percent, mainly cobbles.
A horizon - Hue: 7.5YR and 5YR.
Value: 4 or 5 dry.
Chroma: 3 through 6 dry and moist.
Calcium carbonate equivalent in the fine earth fraction: 0 to 5 percent.
Reaction: Mildly alkaline or moderately alkaline
Btk or Bt horizons - Hue: 2.5YR or 5YR.
Value: 4 or 5 dry.
Chroma: 3 through 6.
Clay content: 18 to 30 percent, averages 18 to 27 percent after mixing.
Texture: Sandy clay loam in the upper part of the argillic and fine sandy loam or sandy clay loam in the lower part.
Consistence: Moderately hard or hard, dry; very friable or friable; moist; slightly sticky or sticky.
Effervescence: Noneffervescent to strongly effervescent.
Reaction: Slightly alkaline or moderately alkaline.
Calcium carbonate equivalent in the fine earth fraction: 0 to 10 percent in the upper part and 15 to 30 percent in the lower part.
Bkq horizon - Hue: 2.5YR, 5YR or 7.5YR.
Value: 5 or 6 dry, 4 or 5 moist.
Chroma: 4 through 6 dry and moist.
Clay content: 6 to 15 percent.
Rock fragments: 60 to 75 percent; mainly gravel with cobbles and stones.
Consistence: Slightly hard or moderately hard, dry; very friable or friable, moist; nonsticky or slightly sticky, wet.
Reaction: Moderately alkaline or strongly alkaline.
Calcium carbonate equivalent in the fine earth fraction: 30 to 50 percent.
Other features: 5 to 15 percent visible secondarycalcium carbonate. 0 to 30 percent discontinuous silica and calcium carbonate cemented lenses.
Bqkm horizon - Hue: 5YR or 7.5YR.
Value: 6 through 8 dry, 5 through 7 moist.
Chroma: 3 through 6 dry and moist.
Rupture resistance: Continuously very strongly cemented or indurated duripan. Subhorizons are moderately cemented or strongly cemented in some pedons.
Cementation: Silica and calcium carbonate cemented; more than 50 percent of fragments remain after soaking in HCL.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Diamondhil soils are on fan remnants. These soils formed in mixed alluvium from mainly calcareous sandstone with some limestone and conglomerate. Slope ranges from 2 to 8 percent. Elevations are 3,400 to 4,400 feet. The climate is warm and arid with cool, moist winters and hot, dry summers. The mean annual precipitation is 7 to 9 inches; mean air annual temperature is 51 to 56 degrees F., and the frost-free season is 130 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Annroma, Bludiamond and Irongold series. Annroma and Irongold soils have carbonatic mineralogy, lack argillic horizon and are shallow to a petrocalcic horizon. Bludiamond soils have a thermic temperature regime and have a petrocalcic horizon.
DRAINAGE AND PERMEABILITY: Well drained; high runoff; moderately slow permeability.
USE AND VEGETATION: These soils are used for rangeland and wildlife habitat. The present vegetation is mainly blackbrush.
DISTRIBUTION AND EXTENT: Mojave Desert of southern Nevada; MLRA 30. These soils are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Clark County Area, Nevada, 2006. Proposed in Clark County, Nevada, 1995. The name is coined from Blue Diamond Hill located about 5 miles to the east.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon 0 to 2 inches (A horizon).
Argillic horizons - 2 to 19 inches (Btk1 and Btk2 horizons).
Calcic horizon -10 to 31 inches (Btk2 and Bkq horizons)
Duripan - 31 to 60 inches (Bqkm horizon)
Particle-size control section - 2 to 19 inches (Btk1 and Btk2 horizons).