LOCATION MAGNA UTEstablished Series
TAXONOMIC CLASS: Fine, mixed, active, mesic Typic Calciaquolls
TYPICAL PEDON: Magna silty clay--meadow pasture. (Colors are for dry soil unless otherwise noted.)
Ag1--0 to 2 inches; dark gray (10YR 4/1) silty clay, very dark gray (10YR 3/1) moist; moderate very fine granular structure; hard, firm, moderately sticky and moderately plastic; strongly effervescent; moderately alkaline (pH 8.2); clear smooth boundary. (2 to 8 inches thick)
Ag2--2 to 12 inches; gray (10YR 5/1) silty clay, black (10YR 2/1) moist; moderate fine subangular blocky structure; very hard, very firm, moderately sticky and very plastic; many fine and few medium roots; few medium and fine pores; many thin veins of white salt crystals; strongly effervescent; moderately alkaline (pH 8.4); clear smooth boundary. (0 to 11 inches thick)
Bkg--12 to 28 inches; light gray (5Y 7/1) silty clay, dark gray (5YR 4/1) moist; massive; very hard, very firm, moderately sticky and very plastic; common fine and few medium roots; common medium and fine pores; strongly effervescent; secondary carbonate segregated in the matrix in few fine veins; moderately alkaline (pH 8.4); gradual wavy boundary. (8 to 16 inches thick)
Agb--28 to 38 inches; gray (10YR 5/1) silty clay loam, black (10YR 2/1) moist; massive; very hard, very firm, moderately sticky and very plastic; few medium and fine roots; common medium pores; few snail shells; strongly effervescent; moderately alkaline (pH 8.2); clear smooth boundary. (0 to 10 inches thick)
Cg1--38 to 60 inches; gray (10YR 6/1) silty clay loam, very dark gray (10YR 3/1) moist; massive; hard, firm, moderately sticky and moderately plastic; few medium and fine roots; common medium pores; few snail shells; strongly effervescent; moderately alkaline (pH 8.2); clear smooth boundary. (7 to 22 inches thick)
Cg2--60 to 70 inches; light gray (5Y 7/1) silty clay loam, gray (5Y 5/1) moist; massive; very hard, very firm, moderately sticky and moderately plastic; common medium and fine pores; strongly effervescent; moderately alkaline (pH 8.4); clear smooth boundary. (7 to 17 inches thick)
Cg3--70 to 76 inches; gray (5Y 5/1) silty clay, black (5Y 2/1) moist; massive; very hard, very firm, moderately sticky and very plastic; slightly effervescent; moderately alkaline (pH 8.2)
TYPE LOCATION: Salt Lake County, Utah; about 500 feet east of radio tower and 100 feet south of road at 1300 West and 2300 South; approximately 2,100 feet south and 500 feet east of the northwest corner of section 23, T. 1 S., R. 1 W.; USGS Salt Lake City South 7.5 minute topographic quadrangle; 40 degrees 43 minutes 13 seconds north latitude and 111 degrees 55 minutes 41 seconds west longitude, NAD83; UTM zone 12N 421626E, 4508113N, NAD83.
RANGE IN CHARACTERISTICS:
Soil moisture - These soils are saturated with water during part of the year within a depth of 24 inches; the upper part of the moisture control section is dry during summer months in normal years; Aquic moisture regime during seasonal periods of saturation and reduction.
Mean annual soil temperature - 47 to 54 degrees F.
Mean summer soil temperature - 65 to 75 degrees F.
Mollic epipedon thickness - 10 to 16 inches.
Particle-size control section - Clay content: Averages 35 to 50 percent.
Other features - Some pedons have Oi horizons up to 3 inches thick.
Ag horizons - Hue: 10YR or 2.5Y.
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 1 or 2, dry or moist.
Structure: Weak or moderate granular or thin platy structure in the upper portion and moderate to weak subangular blocky structure in the
lower portion.
Consistence: Hard or very hard dry.
Reaction: Moderately alkaline or strongly alkaline.
Calcium carbonate equivalent: 12 to 35 percent.
Bkg horizon - Hue: 10YR through 5Y.
Value: 5 through 7 dry, 3 through 5 moist.
Chroma: 1 or 2, dry or moist.
Texture: Silty clay loam or silty clay.
Structure: Moderate very coarse prismatic, subangular blocky, or massive.
Reaction: Moderately alkaline or strongly alkaline.
Calcium carbonate equivalent: 18 to 40 percent.
Cg horizons - Hue: 10YR through 5Y.
Value: 5 through 7 dry, 2 through 6 moist.
Chroma: 1 or 2, dry or moist.
Texture: Silty clay loam or silty clay.
Reaction: Moderately alkaline or strongly alkaline.
Calcium carbonate equivalent: 18 to 40 percent.
COMPETING SERIES: There are currently no other series in this family.
GEOGRAPHIC SETTING: Magna soils occur on smooth to undulating flood plains, lake plains, and low lake terraces. Slopes are 0 to 2 percent. Elevations range from 4,200 to 5,800 feet. The soils formed in alluvium and reworked lacustrine deposits derived from mixed sedimentary and igneous rocks. The climate is dry subhumid. The mean annual precipitation is 10 to 16 inches. The mean annual temperature is 45 to 52 degrees F. and the mean summer temperature is 65 to 75 degrees F. The frost-free period is 120 to 150 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Chipman and Ironton soils. Chipman soils are fine-silty. Ironton soils are coarse-loamy.
DRAINAGE AND PERMEABILITY: Poorly drained; very high surface runoff; slow or very slow permeability (low to moderately high saturated hydraulic conductivity). Endosaturation is present with an apparent seasonal high water table between the soil surface and 2 feet (very shallow to moderately deep free water occurrence classes) between April and August. Cumulative annual duration class is Common. Drained phases are recognized. These soils are susceptible to occasional flooding for long periods between April and June.
USE AND VEGETATION: Magna soils are used for pasture, irrigated cropland, and industrial development. The native vegetation is inland saltgrass, wiregrass, sedges, quackgrass, and foxtail.
DISTRIBUTION AND EXTENT: Northwestern Utah. These soils are not extensive with about 6,200 acres of the series mapped to date. MLRA 28A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona.
SERIES ESTABLISHED: Salt Lake County, Utah, 1969.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to a depth of 12 inches (Ag1 and Ag2 horizons).
Calcic horizon - The zone from 12 to 28 inches (Bkg horizon).
Aquic conditions - The conditions of endosaturation, reduction, and redoximorphic features between the soil surface and 24 inches at certain times during normal years (parts of the Ag1, Ag2, and Bkg horizons).
Particle-size control section - The zone from 10 to 40 inches (Bkg and Agb horizons and parts of the Ag2 and Cg1 horizon).
This revision of February 2006 updates the taxonomic class from Fine, mixed, superactive, mesic Typic Calciaquolls based on lab data for adjacent soils and property data in NASIS.
Magna soils in the soil survey of Box Elder County, Utah, Eastern Part (UT602) are a taxadjunct to the series because they are drier in the upper part of the profile and classify as Fine, mixed, active, mesic Aeric Calciaquolls.