LOCATION MELLOR UT+ID NVEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Xeric Natrargids
TYPICAL PEDON: Mellor silt loam--rangeland. (Colors are for air dry soil unless otherwise noted.)
A1--0 to 5 cm; light brownish gray (10YR 6/2) silt loam, dark grayish brown (10YR 4/2) moist; moderate medium platy structure; soft, friable, slightly sticky and slightly plastic; common very fine roots; many very fine vesicular pores; strongly effervescent; strongly alkaline (pH 8.6); abrupt smooth boundary.
A2--5 to 18 cm; pale brown (10YR 6/2) silt loam, dark grayish brown (10YR 4/2) moist; weak thin platy structure parting to moderate medium granular in the upper 3 inches and weak medium subangular blocky structure below; soft, friable, slightly sticky and slightly plastic; common very fine roots; many very fine vesicular pores; strongly effervescent; strongly alkaline (pH 8.6); abrupt smooth boundary. (combined thickness of A horizons 11 to 23 cm thick)
Btn1--18 to 30 cm; light brown (7.5YR 6/3) silty clay loam, brown (7.5YR 5/4) moist; moderate coarse prismatic structure parting to strong medium angular blocky; hard, firm, moderately sticky and very plastic; few fine and very fine roots; common very fine and few fine pores; common moderately thick clay films on faces of peds; strongly effervescent; very strongly alkaline (pH 9.6); clear smooth boundary.
Btn2--30 to 41 cm; light brown (7.5YR 6/3) silty clay loam, brown (7.5YR 5/4) moist; strong medium angular blocky structure; very hard, firm, moderately sticky and moderately plastic; few very fine and few fine roots; common very fine and few fine pores; common moderately thick clay films on faces of peds; strongly effervescent; very strongly alkaline (pH 9.6); clear smooth boundary. (combined thickness of Btn horizons 18 to 33 cm thick)
Bk1--41 to 56 cm; pink (7.5YR 7/3) silty clay loam, light brown (7.5YR 6/3) moist; moderate fine angular blocky structure; very hard, firm, moderately sticky and moderately plastic; few very fine and few fine roots; few very fine pores; violently effervescent, carbonates are disseminated and in veins; very strongly alkaline (pH 9.6); clear smooth boundary.
Bk2--56 to 71 cm; pink (7.5YR 7/3) silty clay, light brown (7.5YR 6/4) moist; moderate medium subangular blocky structure; very hard, very firm, moderately sticky and very plastic; few very fine roots; few very fine pores; violently effervescent, carbonates are disseminated and in veins and fine soft nodules; very strongly alkaline (pH 9.6); clear smooth boundary.
Bk3--71 to 102 cm; pink (7.5YR 7/3) silty clay loam, light brown (7.5YR 6/4) moist; common, medium, distinct dark yellowish brown (10YR 4/4) mottles; weak medium platy structure; very hard, firm, moderately sticky and moderately plastic; few very fine roots; few very fine pores; violently effervescent, carbonates are disseminated and in veins; very strongly alkaline (pH 9.6); clear wavy boundary. (combined thickness of Bk horizons 38 to 78 cm thick)
C1--102 to 124 cm; very pale brown (10YR 7/3) silt loam, brown (10YR 5/3) moist; massive; slightly hard, friable, slightly sticky and moderately plastic; few very fine pores; violently effervescent; very strongly alkaline (pH 9.6); clear smooth boundary. (20 to 60 cm thick)
C2--124 to 152 cm; very pale brown (10YR 7/3) very fine sandy loam, brown (10YR 5/3) moist; few medium faint yellowish brown (10YR 5/6) mottles; massive, slightly hard, very friable, slightly sticky and slightly plastic; few fine roots; few very fine pores; violently effervescent; very strongly alkaline (pH 9.6).
TYPE LOCATION: Sanpete County, Utah; 6 miles north of Fayette and 1/2 mile west of highway UT 28; about 2,470 feet north and 1,600 feet west of the southeast corner of sec. 27 T. 17 S., R. 1 W.; USGS Hells Kitchen Canyon SW, Utah 7.5 minute quadrangle; latitude 39 degrees 18 minutes 5 seconds N and longitude 111 degrees 54 minutes 22 seconds W; NAD 83.
RANGE IN CHARACTERISTICS:
Soil moisture: Usually dry; moist in winter and spring and for brief periods in late summer due to convection storms; aridic bordering on xeric soil moisture regime.
Mean annual soil temperature ranges: 8.0 to 12.0 degrees C.
Thickness of the A and Btn horizons: 20 to 65 cm
Other features: E horizons are present in some pedons.
Particle-size control section - Clay content: 27 to 35 percent.
Sand content: Less than 15 percent coarser than very fine sand
A horizon
Hue: 10YR or 7.5YR.
Value: 6 or 7 dry, 4 or 5 moist.
Chroma: 2 through 4.
Reaction: Moderately alkaline or strongly alkaline.
Btn horizon
Hue: 10YR or 7.5YR.
Value: 5 through 7 dry, 4 through 6 moist.
Chroma: 2 through 4.
Texture: Clay loam or silty clay loam.
Sodicity (SAR): More than 13.
Reaction: Moderately alkaline through very strongly alkaline.
Effervescence: Strongly effervescent or violently effervescent.
Bk and C horizon
Hue: 2.5Y, 10YR, 7.5YR.
Value: 5 through 8 dry, 4 through 6 moist.
Chroma: 2 through 4.
Texture: Silty clay loam, clay loam, very fine sandy loam, silt loam, or silty clay; subhorizons of gravelly loamy fine sand are in the lower part of some pedons.
Clay content: 18 to 35 percent.
Effervescence: Strongly effervescent or violently effervescent.
COMPETING SERIES: These are the Knull and McDermott series.
Knull soils have less than 27 percent clay in the particle-size control section. McDermott soils have mean annual soil temperatures greater than 12.0 degrees C. and include 2.5Y and 5Y hues in the particle-size control section.
GEOGRAPHIC SETTING: The Mellor soils are alluvial fans, alluvial flats, flood plains, lake plains, and lake terraces at elevations of 1,280 to 1,830 meters. Slopes are 0 to 6 percent. They formed in alluvium from sandstone, shale, limestone and lacustrine sediments. The climate is semiarid. Mean annual air temperatures range from 7 to 12 degrees C. Mean summer temperatures are 18.5 to 20.5 degrees C. Average annual precipitation ranges from 200 to 300 mm. Freeze-free period is 100 to 150 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bram, Genola, Harding, Manassa Quaker and Woodrow soils. Bram, Genola, Manassa, Quaker, and Woodrow soils do not have a natric horizon. Harding soils have a fine particle-size control section.
DRAINAGE AND PERMEABILITY: Well and moderately well drained; slow to high runoff; slow permeability; moderately low saturated hydraulic conductivity.
USE AND VEGETATION: These soils are used for livestock grazing. Potential vegetation is greasewood, shadscale and squirreltail.
DISTRIBUTION AND EXTENT: Central and northern Utah, western Nevada and southern Idaho. MLRA D28A, D26 B11. The series is moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Richfield Area, Utah, 1947.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from 0 to 18 cm (A1, A2 horizons)
Albic horizon - The zone from 0 to 18 cm (A1, A2 horizons)
Natric horizon - The zone from 18 to 41 cm (Btn1, Btn2 horizons)
Secondary carbonates - The zone from 41 to 102 cm (Bk1, Bk2, Bk3 horizons)
Particle-size control section - The zone from 18 to 41 cm (Btn1, Btn2 horizons).
In July 1994 the classification changed from xerollic to xeric based on the Aridisol amendment.