LOCATION MORMON MESA NV+AZ
Established Series
Rev. LNL/ELS/ET
11/2015
MORMON MESA SERIES
The Mormon Mesa series consist of shallow over petrocalcic, well drained soils that formed in material influenced by calcareous loess over mixed alluvium from predominantly limestone sources. The Mormon Mesa soils are on summits of fan remnants and mesas. Slope ranges from 0 to 15 percent. The mean annual precipitation is about 5 inches and the mean annual temperature is about 65 degrees F.
TAXONOMIC CLASS: Loamy, carbonatic, thermic, shallow Calcic Petrocalcids
TYPICAL PEDON: Mormon Mesa fine sandy loam, rangeland and wildlife habitat. (Colors are for dry soil unless otherwise stated.)
A--0 to 2.5 inches; light reddish brown ( 5YR 6/4) fine sandy loam, reddish brown (5YR 4/3) moist; moderate medium and thin platy structure; slightly hard, friable, nonsticky and slightly plastic; few fine roots; many very fine interstitial and many fine vesicular pores; violently effervescent; moderately alkaline (pH 8.2); abrupt smooth boundary. (2 to 5 inches thick)
Bk1--2.5 to 10 inches; light reddish brown (5YR 6/4) fine sandy loam, reddish brown (5YR 4/3) moist; weak medium and fine granular structure; slightly hard, very friable, nonsticky and nonplastic; few fine roots; few fine tubular and many very fine interstitial pores; few fine prominent very pale brown (10YR 8/2) calcium carbonate coatings in root channels; violently effervescent; moderately alkaline (pH 8.4); clear wavy boundary.
Bk2--10 to 16 inches; reddish brown (5YR 5/4) fine sandy loam, reddish brown (5YR 4/4) moist; massive; slightly hard, very friable, nonsticky and nonplastic; few fine roots; many very fine interstitial pores; many very fine and fine prominent white (10YR 8/1) calcium carbonate masses; violently effervescent; strongly alkaline (pH 8.5); abrupt wavy boundary. (Combined thickness of the Bk horizons is 8 to 18 inches.)
2Bkm--16 to 60 inches; white and pink (7.5YR 8/4 and 7.5YR 8/1) indurated hardpan, light brown (7.5YR 6/4) moist; massive; very rigid, very rigid; the upper 2 inches have many very fine laminae; violently effervescent; moderately alkaline (pH 8.4).
TYPE LOCATION: Clark County, Nevada; on Mormon Mesa about 3 miles northeast on U.S. Highway 91 from junction with Nevada State Highway 12 to 1/2 mile south of highway; approximately 800 feet north and 1,300 feet east of the southwest corner of section 28, T. 13 S., R. 69 E., Mount Diablo base line and meridian.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually dry, moist in some part during winter and spring and intermittingly moist in the upper part following summer convection storms; typic aridic soil moisture regime.
Soil Temperature - 59 to 72 degrees F.
Depth to calcic horizon 2 to 6 inches.
Depth to petrocalcic horizon - 10 to 20 inches.
Control section - Clay content: 5 to 15 percent.
Rock fragments: Averages 0 to 20 percent, predominantly gravel or cobble size pan fragments, with 20 to 35 percent in any given subhorizon.
Profile reaction: Moderately alkaline or strongly alkaline.
Calcium carbonate equivalent in the fine earth fraction: 40 to 60 percent.
A horizon - Hue: 5YR or 7.5YR.
Value: 6 or 7 dry, 4 or 5 moist.
Chroma: 2 through 4 dry and moist.
Bk horizons - Hue: 5YR or 7.5YR.
Value: 6 through 8 dry, 4 through 6 moist.
Chroma: 2 through 4 dry and moist.
Clay content: 5 to 15 percent.
Texture: Fine sandy loam or sandy loam.
Rock fragments: Averages 0 to 35 percent, predominantly gravel or cobble size pan fragments.
Structure: Massive or subangular blocky.
Consistence: Soft or slightly hard, friable or very friable, nonsticky or slightly sticky.
Secondary carbonates: When rock or pan fragments are present in the profile, clasts may contain many to common calcium carbonate coats and pendants on the vertical and undersides of fragments. Common very thin or thin calcium carbonate coats, filaments and seams.
2Bkm horizon - Hue: 7.5YR or 10YR.
Value: 7 or 8 dry, 6 through 8 moist.
Chroma: 0 through 4.
Thickness: Ranges from 4 feet to more than 20 feet.
COMPETING SERIES: These are the
Bard (NV),
Crossen (TX),
Upton (TX, NM),
Woda (NV) series. Bard soils have less than 4 foot thick Bkm (petrocalcic) horizons. Crossen soils have 3 to 20 inch thick petrocalcic horizons. Upton soils form in calcareous materials and contain 15 to 30 percent clay in the control section. Woda soils contain 20 to 30 percent clay in the control section.
GEOGRAPHIC SETTING: Mormon Mesa soils are on summits of fan remnants and mesas. Slope ranges from 0 to 15 percent. These soils formed in material influenced by calcareous loess over mixed alluvium from predominantly limestone sources. Elevations are 1,800 to 3,000 feet. The climate is low latitude desert, with mild winters and very hot summers. Precipitation is greatest in the winter with a lesser secondary peak in summer, typical of the Mojave Desert. The mean annual rainfall is 4 to 7 inches. The mean annual temperature is 57 to 70 degrees F.; average January temperature is 45 degrees F., and average July temperature is 83 degrees F. The frost free season is 220 to 300 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Arizo,
Flattop,
St. Thomas,
Tonopah, and
Toquop soils. Arizo and Tonopah soils are very deep and have sandy-skeletal control sections.Flattop soils have prismatic, sodium-affected clay loam Bt horizons. St. Thomas soils are very shallow or shallow over limestone and have loamy-skeletal control sections. Toquop soils are very deep sandy soils.
DRAINAGE AND PERMEABILITY: Well drained; very high runoff; moderately rapid permeability.
USE AND VEGETATION: These soils are used for rangeland and wildlife habitat. The vegetation is scattered white bursage, yucca, and creosotebush with some big galleta and Indian ricegrass. Many annuals grow in areas with sandy A1 horizons.
DISTRIBUTION AND EXTENT: Mojave Desert of southern Nevada and northwestern Arizona; MLRA 30. These soils are extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: PHOENIX, ARIZONA
SERIES ESTABLISHED: Clark County (Virgin River Area), Nevada, 1939.
REMARKS: Diagnostic horizons and features recognized in this pedon
Ochric epipedon - 0 to 2 1/2 inches. (A horizon).
Calcic horizon 10 to 16 inches. (Bk1 and Bk2 horizons).
Petrocalcic horizon - 16 to 60 inches. (2Bkm horizon).
Particle size control section 10 to 16 inches. (Bk2 horizon).
Responsibility for this series was transferred from Davis to Phoenix 11/2015. The last revision to the series was 4/2006. ET
National Cooperative Soil Survey
U.S.A.