LOCATION BROBETT UTEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, active, mesic Haploxeralfic Argidurids
TYPICAL PEDON: Brobett loam--rangeland. (Colors are for air-dry soil unless otherwise stated).
A--0 to 3 inches; brown (l0YR 4/3) loam, dark brown (l0YR 3/3) moist; moderate medium platy structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine and fine vesicular and tubular pores; l0 percent pebbles; slightly calcareous; carbonates are disseminated; mildly alkaline (pH 7.8); clear smooth boundary. (2 to 5 inches thick)
Bt--3 to 8 inches; pale brown (l0YR 6/3) gravelly loam, yellowish brown (l0YR 5/4) moist; moderate medium platy structure; slightly hard, friable, sticky and plastic; many very fine and common fine and medium roots; many very fine and fine and common medium tubular pores; few thin clay films on faces of peds 20 percent pebbles; slightly calcareous; carbonates are disseminated; moderately alkaline (pH 8.2); clear wavy boundary. (3 to 9 inches thick)
Bqkl--8 to l7 inches; very pale brown (l0YR 7/4) extremely gravelly sandy loam, yellowish brown (l0YR 5/4) moist; strong medium platy structure; hard, very firm, slightly sticky and slightly plastic; common very fine and few fine and medium roots; common very fine and fine tubular pores; 60 percent pebbles, about one fourth of which are pebble size pan fragments; common coarse irregular silica nodules; strongly calcareous; carbonates are disseminated; strongly alkaline (pH 8.6); clear wavy boundary.
Bqk2--l7 to 30 inches; very pale brown (l0YR 7/3) very gravelly sandy loam, light yellowish brown (l0YR 6/4) moist; massive; very hard, very firm; few very fine, fine and medium roots; few very fine tubular pores; 50 percent pebbles, about one-fourth of which are pebble size pan fragments; common coarse irregular silica nodules; strongly calcareous; visible soft powdery carbonates in the matrix; moderately alkaline (pH 8.4); clear wavy boundary. (Combined thickness of the Bqk horizon is 18 to 27 inches).
Bqkm--30 inches; strongly cemented fractured duripan with fractures greater than 4 inches apart; strongly cemented laminar cap l/8 to l/4 inches thick; strongly calcareous; moderately alkaline (pH 8.4).
TYPE LOCATION: Box Elder County, UT; about 6 miles south of Etna; l,700 feet north and l,200 feet west of the southeast corner of sec. l, T. l0 N., R. l9 W.
RANGE IN CHARACTERISTICS: A strongly silica cemented hardpan is between 20 and 40 inches. The particle-size control section averages l2 to l7 percent clay and 35 to 60 percent rock fragments. The mean annual soil temperature is 49 to 52 degrees F. The moisture control section is usually dry, but is moist in some part 25 to 35 percent of the time the soil temperature is above 4l degrees F. It is dry in all parts for 45 to 60 consecutive days following the summer solstice.
The A horizon has value 4 to 7 dry, 3 or 4 moist. It is mildly alkaline or moderately alkaline and is noncalcareous or slightly calcareous.
The Bt horizon has value of 4 or 5 moist and chroma of 3 or 4. It commonly is gravelly loam and less commonly very gravelly loam. Clay films range from few to common. It is slightly calcareous to strongly calcareous.
The Bqk horizon has a value 7 or 8 dry, 5 or 6 moist and chroma of 3 or 4. It commonly is very gravelly sandy loam, extremely gravelly sandy loam, or very gravelly loam. It is moderately alkaline or strongly alkaline.
The Bqkm horizon is a continuous duripan which is weakly cemented or strongly cemented. It has value of 7 or 8 dry and chroma of 3 or 4. It is moderately alkaline or strongly alkaline.
COMPETING SERIES: There are no other series in this family, but similar families are the Brock, Prey, and Vinini soils. The Brock and Vinini soils have a shallow hardpan and an indurated layer within 40 inches of the surface. The Prey soils have a fine-loamy control section.
GEOGRAPHIC SETTING: The Brobett soils are on dissected bajadas at elevations of 5,000 to 5,400 feet. Slopes are 3 to 8 percent. These soils formed in alluvium from rhyolite and quartzite with influences of tuffaceous material. The mean annual temperature is 47 to 49 degrees F. The average annual precipitation is 8 to l2 inches. The freeze-free period is about l20 to l60 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Puett, Plegomir and Swanner soils. The Puett soils lack an argillic horizon. The Plegomir soils have an indurated hardpan at a depth of l0 to 20 inches. The Swanner soils have bedrock at a depth of l0 to 20 inches.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; above hardpan moderate permeability.
USE AND VEGETATION: These soils are used for rangeland. The potential vegetation is Wyoming big sagebrush, shadscale, bluebunch wheatgrass, and Indian ricegrass.
DISTRIBUTION AND EXTENT: Brobett soils are located in northwest Utah and are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Box Elder County, Utah - Western Part l984
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Duripan - a weakly cemented to strongly cemented layer of both lime and silica at a depth of about 20 to 40 cm (Bqkm horizon)
Argillic horizon - the zone from approximately 3 to 8 inches (Bt horizon)
Haploxerollic feature - the duripan is not indurated in any subhorizon.