LOCATION LASIL UTEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Typic Natrixeralfs
TYPICAL PEDON: Lasil silt loam--rangeland. (Colors are for dry soil unless otherwise noted.)
E--0 to 5 inches; light brownish gray (10YR 6/2) silt loam, very dark grayish brown (10YR 3/2) moist; moderate medium platy structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine roots; many very fine pores; moderately alkaline (pH 7.9); abrupt smooth boundary. (5 to 13 inches thick)
EB--5 to 9 inches; light brownish gray (10YR 6/2) silt loam, dark grayish brown (10YR 4/2) moist; weak medium prismatic structure; hard, friable, slightly sticky and slightly plastic; few very fine roots; many very fine pores; slightly effervescent; 1 percent calcium carbonate equivalent; moderately alkaline (pH 7.9); clear smooth boundary. (0 to 5 inches thick)
Btkn1--9 to 14 inches; light gray (10YR 7/2) clay loam, dark grayish brown (10YR 4/2) moist; moderate medium prismatic structure; extremely hard, firm, moderately sticky and moderately plastic; few very fine roots; many very fine pores; common faint clay films on faces of peds; violently effervescent; 25 percent calcium carbonate equivalent; secondary carbonates are disseminated; moderately alkaline (pH 8.4); clear smooth boundary. (5 to 12 inches thick)
Btkn2--14 to 19 inches; light gray (2.5Y 7/2) silt loam, light olive brown (2.5Y 5/3) moist; weak medium platy structure; extremely hard, firm, moderately sticky and moderately plastic; few very fine roots; many very fine and fine pores; few faint clay films on faces of peds; violently effervescent; 34 percent calcium carbonate equivalent; secondary carbonates are disseminated; strongly alkaline (pH 8.8); clear smooth boundary. (3 to 12 inches thick)
Bk--19 to 29 inches; light gray (5Y 7/2) silty clay loam, olive (5Y 5/3) moist; massive; extremely hard, friable, moderately sticky and moderately plastic; many very fine and fine pores; common fine distinct yellowish brown (10YR 5/4) masses of iron accumulation; violently effervescent; 25 percent calcium carbonate equivalent; secondary carbonates are disseminated; strongly alkaline (pH 8.8); clear smooth boundary. (5 to 10 inches thick)
C--29 to 48 inches; light gray (5Y 7/2) silt loam, olive gray (5Y 5/2) moist; massive; hard, friable, slightly sticky and slightly plastic; many very fine and fine pores; common medium dark yellowish brown (10YR 4/4) masses of iron accumulation; violently effervescent; 19 percent calcium carbonate equivalent; strongly alkaline (pH 8.8); clear smooth boundary. (7 to 18 inches thick)
2C--48 to 66 inches; light gray (2.5Y 7/2) silt loam, grayish brown (2.5Y 5/2) moist; common coarse distinct brown (10YR 4/3) masses of iron accumulation; massive; soft, very friable, slightly sticky and nonplastic; interstitial pores; strongly effervescent; 14 percent calcium carbonate equivalent; strongly alkaline (pH 8.6); abrupt smooth boundary. (0 to 18 inches thick)
3C--66 to 78 inches; light gray (2.5Y 7/2) fine sand, grayish brown (2.5Y 5/2) moist; single grain; loose, nonsticky and nonplastic; few coarse distinct yellowish brown (10YR 5/4) masses of iron accumulation; strongly alkaline (pH 9.0).
TYPE LOCATION: Salt Lake County, Utah; at about 1900 South and 3600 West Street; approximately 1,100 feet south and 175 feet west of the center of section 17, T. 1 S., R. 1 W.; USGS Salt Lake City South 7.5 minute topographic quadrangle; 40 degrees 43 minutes 48 seconds north latitude and 111 degrees 58 minutes 40 seconds west longitude, NAD83; UTM zone 12N 417424E, 4509246N, NAD83.
RANGE IN CHARACTERISTICS:
Soil moisture - Typically moist in winter and spring, dry in summer and fall; the soils are dry in all parts of the moisture control section for more than 60 consecutive days following the summer solstice; Xeric moisture regime that borders on aridic.
Mean annual soil temperature - 49 to 56 degrees F.
Mean summer soil temperature - 65 to 75 degrees F.
Ochric epipedon thickness - 3 to 11 inches.
Particle-size control section - Clay content: 18 to 35 percent.
E and EB horizons - Hue: 10YR or 2.5Y.
Value: 5 or 6 dry, 3 or 4 moist; Moist and dry color values do not occur together as dark as 5 dry and 3 moist.
Chroma: 2 or 3, dry or moist.
Texture: Silt loam or loam.
Effervescence: Noneffervescent to strongly effervescent.
Reaction: Neutral to strongly alkaline.
Salinity (EC): 2 to 32 mmhos/cm.
Btkn horizons - Hue: 10YR or 2.5Y.
Value: 6 or 7 dry, 4 or 5 moist.
Chroma: 2 through 4, dry or moist.
Texture: Silt loam, silty clay loam, or clay loam.
Clay content: 18 to 35 percent.
Structure: Weak to strong prismatic or columnar.
Clay films: Few faint to distinct continuous clay films on faces of peds.
Effervescence: Strongly effervescent or violently effervescent.
Calcium carbonate equivalent: 3 to 40 percent.
Reaction: Moderately alkaline to very strongly alkaline (up to pH 9.6).
Salinity (EC): 2 to 32 mmhos/cm.
Sodicity (SAR): 15 to 40.
Exchangeable sodium: 15 to 60 percent.
Bk and C horizons - Hue: 10YR through 5Y.
Value: 6 through 8 dry, 4 through 6 moist.
Chroma: 2 or 3, dry or moist.
Texture: Silty clay loam, silt loam, loam, sandy clay loam, and sandy loam; some pedons have texture of fine sand or sand below 40 inches.
Calcium carbonate equivalent: 10 to 40 percent.
Reaction: Moderately alkaline to very strongly alkaline (up to pH 11.0).
Salinity (EC): 4 to 32 mmhos/cm.
Sodicity (SAR): 15 to 40.
Exchangeable sodium: 40 to 90 percent.
Other features: Some pedons have discontinuous weak cementation.
COMPETING SERIES: There are currently no other series in this family.
GEOGRAPHIC SETTING: Lasil soils are on smooth to channeled low lake terraces and lake plains. They formed in calcareous lacustrine deposits derived from mixed sedimentary and igneous rocks. Slopes are 0 to 3 percent. Elevations range from 4,200 to 4,500 feet. The climate is dry subhumid. The mean annual precipitation is 12 to 16 inches. The mean annual temperature is 47 to 54 degrees F. and the mean summer temperature is 65 to 75 degrees F. The frost-free period is 120 to 190 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Decker, Saltair, and Jordan soils. Decker soils lack natric horizons and have control sections that have more than 15 percent coarser than very fine sand. Saltair soils have salic horizons and lack natric horizons. Jordan soils have salic horizons.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; medium surface runoff; slow permeability (moderately low or moderately high saturated hydraulic conductivity). Endosaturation is present with an apparent seasonal high water table between 2.5 and 4.0 feet (moderately deep or deep free water occurrence classes) between April and September. Cumulative annual duration class is Common. Drained phases occur in areas reclaimed for cropland.
USE AND VEGETATION: Lasil soils are used for rangeland and wildlife habitat, except for small areas that are reclaimed and used for irrigated cropland. The native vegetation is black greasewood, pickleweed, inland saltgrass, and rubber rabbitbrush.
DISTRIBUTION AND EXTENT: Northwestern Utah. These soils are moderately extensive. MLRA 28A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona.
SERIES ESTABLISHED: Salt Lake Area, Utah, 1965.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 9 inches (E and EB horizons).
Albic horizon - The zone from the soil surface to 9 inches (E and EB horizons).
Natric horizon - The zone from 9 to 19 inches (Btkn1 and Btkn2 horizons).
Calcic horizon - The zone from 9 to 29 inches (Btkn1, Btkn2, and Bk horizons).
Endosaturation feature - The condition of ground water with an upper boundary between 30 and 50 inches at certain times during normal years (parts of the C horizons).
Particle-size control section - The zone from 9 to 19 inches (Btkn1 and Btkn2 horizons).
The revision of April 2005 updated the taxonomic class from Fine-silty, mixed, superactive, mesic Typic Natrustalfs based on the assumed moisture regime being xeric instead of ustic.
The Lasil series is currently mapped in three soil survey areas in Utah. There are some phases which have the average depth to the seasonal high saturation within 30 inches of the soil surface. Such phases should classify in the subgroup of Aquic Natrixeralfs. Future study is needed to determine whether a new series concept should be developed for these wetter phases of Lasil or whether they should be correlated to the Arave series.
The superactive cation exchange activity class was added in 03/2003 to the taxonomic classification by the National Soil Survey Center on request of the Reno MLRA office, without review of the soil series property data.
ADDITIONAL DATA: The typical pedon at the series type location has partial characterization data by the Soils Laboratory from Utah State University (USU) Logan, UT and is published on pages 122-123, Table 7 of the Soil Survey of Salt Lake Area, Utah. The pH values in the typical pedon are from saturated paste.