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 E horizons are 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 are 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 is 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.
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 north and longitude 111 degrees 54 minutes 22 seconds west; 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 10.5 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 (weighted average):
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 to 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
Clay content: 27 to 35 percent
Sand content: Less than 15 percent sand coarser than very fine sand
SAR: More than 13
Reaction: Moderately alkaline to very strongly alkaline
Effervescence: Strong to violent
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: Strong to violent
COMPETING SERIES: These are the Knull (ID) and McDermott (CA) 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 on gently to moderately sloping alluvial fans, alluvial flats, flood plains, lake plains, and old lake terraces at elevations of 1,280 to 1,830 m. 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 7.0 to 12.0 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 native range pasture. 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 OFFICE RESPONSIBLE: Reno, Nevada
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 - in the zone from 41 to 102 cm (Bk1, Bk2, Bk3 horizons)
Particle-size control section - the zone from 18 to 41 cm.
In July 1994 the classification changed from xerollic to xeric based on the Aridisol amendment.