LOCATION SIMPER UTEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Typic Durixerolls
TYPICAL PEDON: Simper gravelly loam - on a 5 percent slopes, rangeland. (Colors are for air dry soil unless otherwise noted)
The soil surface is covered with 5 percent cobbles and 35 percent gravel.
A1--0 to 2 inches; grayish brown (10YR 5/2) gravelly loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; soft, very friable, slightly sticky and slightly plastic; common fine and very fine roots; few medium, common fine and very fine pores; 10 percent gravel; mildly alkaline (pH 7.8); clear smooth boundary. (0 to 3 inches thick)
A2--2 to 8 inches; brown (10YR 5/3) gravelly loam, dark brown (10YR 3/3) moist; weak medium granular structure parting to weak fine granular; soft, very friable, slightly sticky and slightly plastic; few medium, common fine and very fine roots; common medium, fine and very fine pores; 20 percent gravel; mildly alkaline (pH 7.8); clear wavy boundary. (5 to 8 inches thick)
Bt--8 to 13 inches; brown (7.5YR 5/4) cobbly clay loam, dark brown (7.5YR 4/4) moist; moderate medium subangular blocky structure; slightly hard, firm, sticky and plastic; common medium, fine and few very fine roots; few medium, common fine and many very fine pores; common distinct clay films on faces of peds and lining pores; 25 percent cobbles; mildly alkaline (pH 7.8); clear wavy boundary. (5 to 14 inches thick)
Btk--13 to 21 inches; light brown (7.5YR 6/4) cobbly clay loam, strong brown (7.5YR 5/6) moist; moderate medium subangular blocky structure; hard, firm, sticky and plastic; few medium, common fine and few very fine roots; few medium, many fine and very fine pores; few faint clay films on faces of peds and lining pores; 30 percent cobbles; strongly effervescent, carbonates are disseminated; moderately alkaline (pH 8.2); clear irregular boundary. (5 to 9 inches thick)
Bkqm1--21 to 34 inches; very pale brown (10YR 7/4) duripan, light yellowish brown (10YR 6/4) moist; continuously capped by very thin indurated silica laminae; extremely hard, extremely firm, slightly sticky and slightly plastic; few fine and very fine roots matted on indurated silica laminar cap; violently effervescent, carbonates are disseminated; very strongly cemented by silica and carbonates; moderately alkaline (pH 8.4); clear wavy boundary. (13 to 20 inches thick)
Bkq--34 to 41 inches; very pale brown (10YR 7/4) very gravelly sandy loam, light yellowish brown (10YR 6/4) moist; very hard, very firm, slightly sticky and slightly plastic; 40 percent gravel; strongly effervescent, carbonates occur in filaments and are disseminated; strongly discontinuous cementation by silica and carbonates; moderately alkaline (pH 8.2); clear wavy boundary. (0 to 8 inches thick)
Bk--41 to 60 inches; light yellowish brown (10YR 6/4) very gravelly sandy loam, yellowish brown (10YR 5/4) moist; massive; slightly hard to soft, very friable, nonsticky and nonplastic; common medium, fine and few very fine pores; 40 percent gravel; strongly effervescent, carbonates occur in filaments and are disseminated; moderately alkaline (pH 8.2).
TYPE LOCATION: Iron County, Utah, about 0.5 miles southwest of Spanish George Spring in Hamlin Valley, about 1,920 feet east and 700 feet north of the southwest corner of sec. 15, T. 32 S., R. 18 W; Steamboat Mtn. Quadrangle; lat. 38 degrees 0 minutes 53 seconds N. and long. 113 degrees 51 minutes 10 seconds W.
RANGE OF CHARACTERISTICS:
Soil moisture - the soil moisture control regime is xeric bordering on aridic.
Mean annual soil temperature - 47 to 52 degrees F.
Particle size control section clay content - 27 to 35 percent
Particle size control section rock fragment content - 15 to 35 percent igneous gravel and cobbles
Depth to duripan - 20 to 40 inches
Thickness of mollic epipedon - 7 to 10 inches
The A horizon has value of 4 or 5 dry, and chroma is 2 or 3. Texture is gravelly sandy loam or gravelly loam. Clay content is 15 to 27 percent. Rock fragment content is 15 to 35 percent.
The Bt horizon has hue of 10YR or 7.5YR, value is 4 or 5 dry and 3 or 4 moist, and chroma is 3 or 4. Texture is gravelly clay loam or cobbly clay loam. Clay content is 27 to 35 percent. Reaction is mildly alkaline or moderately alkaline.
The Btk horizon has hue of 10YR or 7.5YR, value is 6 or 7 dry, and chroma is 3 to 6. Texture is gravelly clay loam, very gravelly clay loam or cobbly clay loam. Clay content is 27 to 35 percent. Calcium carbonate equivalent is 5 to 20 percent. Rock fragment content is 15 to 40 percent.
The Bkqm horizon has a value is 6 or 7 dry and 5 or 6 moist, and chroma is 3 or 4. Continuous capped indurated silica laminae.
The Bk horizon has hue of 10YR or 7.5YR, value is 4 or 5 moist, and chroma is 3 to 6. Texture is gravelly sandy loam, very gravelly sandy loam or extremely gravelly sandy loam. Clay content is 5 to 20 percent. Rock fragment content is 25 to 65 percent. Reaction is moderately alkaline or strongly alkaline. Calcium carbonate equivalent is 15 to 40 percent.
COMPETING SERIES: These are the Drewsgap (OR), Milldam (OR), Sweagert T(CA) series. These soils all lack calcium carbonate accumulations.
GEOGRAPHIC SETTING: Simper soils are on fan terraces. These soils formed in alluvium derived dominantly from basic and intermediate igneous rocks. Elevations are 6,200 to 6,800 feet. Slopes are 2 to 15 percent. The mean annual precipitation is 12 to 14 inches; mean annual air temperature is 45 to 50 degrees F.; and the freeze free period is 90 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bodacious, Itca, and Pass Canyon soils. These soils are shallow to bedrock.
DRAINAGE AND PERMEABILITY: Well drained; medium to high runoff; moderately slow permeability.
USE AND VEGETATION: Rangeland. The present vegetation is Utah juniper, Pinion, Wyoming big sagebrush, blue grama, and crested wheatgrass.
DISTRIBUTION AND EXTENT: Central and Southern Utah; MLRA D28A; This series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Iron County, Iron-Washington Area Soil Survey, Utah, 1997.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the zone from the surface of the soil to 8 inches. This horizon exceeds 7 inches in thickness and is greater than one third its depth to carbonates. (A1 and A2 horizons)
Argillic horizon - the zone of clay accumulation from 8 to 21 inches. (Bt and Btk horizons)
Duripan - the zone of silica cementation from 21 to 41 inches with indurated cap. (Bkqm1 and Bkqm2 horizons)
Particle size control section - the zone from 8 to 21 inches.
The classification is based on the "Keys to Soil Taxonomy, Eighth Edition, 1998". The cation exchange activity class is an estimate based on NASIS data.