LOCATION LEEKO UTEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Typic Natrargids
TYPICAL PEDON: Leeko loam, on a northeast facing, linear, 1 percent slope in Castle Valley saltbush, mat saltbush and squirreltail rangeland at an elevation of 5025 feet. (Colors are for dry soil unless otherwise noted.)
The surface is covered by 35 percent subrounded gravel.
E--0 to 2 inches; light yellowish brown (10YR 6/4) loam, dark yellowish brown (10YR 4/4) moist; weak very thin platy structure parting to weak fine subangular blocky; hard, very friable, slightly sticky and slightly plastic; many fine and very fine and common medium vesicular pores; 5 percent gravel; very slightly effervescent; strongly alkaline (pH 9.0); abrupt smooth boundary. (2 to 5 inches thick)
Btn--2 to 7 inches; light brown (7.5YR 6/4) clay loam, brown (7.5YR 4/4) moist; strong medium prismatic structure parting to moderate medium subangular blocky; hard, firm, moderately sticky and moderately plastic; common very fine and few medium and fine roots; common very fine and few fine tubular pores; common distinct clay films on faces of peds; faces of peds are coated with sand grains; very slightly effervescent, carbonates are disseminated; strongly alkaline (pH 9.0); abrupt wavy boundary. (4 to 10 inches thick)
Btkn--7 to 16 inches; light brown (7.5YR 6/4) clay loam, brown (7.5YR 5/4) moist; strong coarse prismatic structure parting to moderate medium subangular blocky; very hard, firm, moderately
sticky and moderately plastic; common fine and very fine and few medium roots; common fine and very fine tubular pores; common distinct clay films on faces of peds; faces of peds are coated with sand grains; strongly effervescent, carbonates are disseminated and segregated in common irregular fine masses in the interior of peds; very strongly alkaline (pH 9.2); gradual irregular boundary. (4 to 16 inches thick)
Bk1--16 to 34 inches; pink (7.5YR 7/4) clay loam, light brown (7.5YR 6/4) moist; weak coarse subangular blocky structure; hard, firm, moderately sticky and moderately plastic; few fine and very fine roots; common very fine and few fine tubular pores; 5 percent gravel; strongly effervescent, carbonates are disseminated and segregated in common irregular fine masses; strongly alkaline (pH 8.8); gradual wavy boundary. (3 to 18 inches thick)
Bk2--34 to 56 inches; very pale brown (10YR 8/3) clay loam, very pale brown (10YR 7/4) moist; massive; hard, firm, moderately sticky and moderately plastic; few fine and very fine roots; few fine and very fine tubular pores; 5 percent cobbles, 5 percent gravel; strongly effervescent, carbonates are disseminated and segregated in common irregular fine and medium masses; strongly alkaline (pH 8.8); clear wavy boundary. (13 to 25 inches thick)
2Bky--56 to 60 inches; white (10YR 8/2) very cobbly clay loam, very pale brown (10YR 7/4) moist; massive; hard, firm, moderately sticky and moderately plastic; few fine and very fine tubular pores; 30 percent cobbles, 20 percent gravel; common 1 mm to 2 mm crystalline gypsum pendents on cobbles; strongly effervescent, carbonates are disseminated and segregated in many irregular fine and medium masses; strongly alkaline (pH 8.8).
TYPE LOCATION: Uintah County, Utah; about 4 miles south of Randlett, Utah on Leland Bench; 1,800 feet west and 800 feet north of the southeast corner of sec. 32, T. 3 S., R. 2 E., USBM; USGS Randlett, Utah quadrangle; lat. 40 degrees 10 minutes 28 seconds N. long. 109 degrees 47 minutes 13 seconds W., NAD 27.
RANGE IN CHARACTERISTICS:
Soil moisture: The soil moisture control section is affected by precipitation that falls evenly throughout the year, with a slight increase in late summer and fall. Typic aridic soil moisture regime.
Mean annual soil temperature: 47 to 50 degrees F.
Surface rock fragments: 0 to 35 percent subrounded gravel from sandstone and quartzite.
Depth to lithologic discontinuity: 40 to 60 inches to horizons with greater than 35 percent rock fragments
Depth to the natric: 2 to 5 inches
Depth to secondary calcium carbonate: 2 to 12 inches
Depth to gypsum accumulation: 40 to 55 inches
Particle-size control section: 27 to 35 percent silicate clay
E horizon:
Hue: 7.5YR or 10YR
Value: 5 or 6 dry, 4 to 6 moist
Chroma: 2 to 4 dry or moist
Rock fragments: 0 to 15 percent subrounded gravel from sandstone and quartzite
Calcium carbonate equivalent: 1 to 10 percent
SAR: 5 to 20
Reaction: strongly alkaline or very strongly alkaline
Btn and Btkn horizon:
Hue: 7.5YR or 10YR
Value: 5 to 8 dry, 4 to 6 moist
Chroma: 3 to 5 dry or moist
Texture: clay loam, sandy clay loam, loam
Rock fragments: 0 to 10 percent subrounded gravel from sandstone and quartzite
Calcium carbonate equivalent: 1 to 10 percent in the Btn horizon and 5 to 25 percent in the Btkn horizon
EC (mmhos/cm): 2 to 8
SAR: 13 to 30
Reaction: strongly alkaline or very strongly alkaline
Bk horizon:
Hue: 7.5YR to 2.5Y
Value: 6 to 8 dry, 4 to 7 moist
Chroma: 2 to 4 dry or moist
Texture: loam, sandy clay loam, clay loam
Rock fragments: 0 to 15 percent subrounded gravel from sandstone and quartzite
Calcium carbonate equivalent: 15 to 40 percent
EC (mmhos/cm): 8 to 16
SAR: 13 to 40
Reaction: moderately alkaline to very strongly alkaline
2Bky horizon:
Hue: 7.5YR to 2.5Y
Value: 6 to 8 dry, 4 to 7 moist
Chroma: 2 to 5 dry or moist
Texture: very cobbly clay loam, extremely cobbly clay loam, very gravelly loam
Rock fragments: 35 to 80 percent subrounded gravel and cobbles from sandstone and quartzite
Calcium carbonate equivalent: 15 to 40 percent
EC (mmhos/cm): 8 to 16
SAR: 13 to 30
Gypsum: 1 to 10 percent
Reaction: moderately alkaline to very strongly alkaline
COMPETING SERIES: Current competitors are the Fajada, Homko, Leebench, Muff, Recapture, Terlco and Uffens series. Competitors prior to the Eighth Edition, 1998 Keys to Soil Taxonomy are Benally, Hadden, Highrock, Pizene, Rusty, and Swasey soils.
Benally, Pizene and Uffens: do not have a calcic horizon.
Fajada, Hadden and Muff: 20 to 40 inches deep to paralithic contact.
Highrock, Rusty and Terlco: moisture control sections affected by xeric precipitation pattterns.
Homko: 0 to 15 percent rock fragments below 40 inches.
Leebench: more than 15 percent rock fragments between the base of the natric horizon and 40 inches.
Recapture: mean annual soil temperature greater than 53 degrees.
Swasey: 20 to 40 inches to a lithic contact of basalt.
GEOGRAPHIC SETTING:
Parent material: alluvium derived from sedimentary and metamorphic rocks.
Landform: strath terraces
Slopes: 0 to 4 percent
Elevation: 4,800 to 5,600 feet
Mean annual air temperature: 45 to 47 degrees F.
Mean annual precipitation: 5 to 8 inches.
Frost-free period: 110 to 125 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Nolava, Shotnick, Tipperary, and the Turzo series.
Nolava soils are on fan remnants, have less than 18 percent total clay and do not have natric horizons.
Shotnick soils are on alluvial flats and have a coarse-loamy particle-size control section.
Tipperary soils are on structural benches and have a sandy particle-size control section.
Turzo soils are on alluvial flats and do not have a natric horizon.
DRAINAGE AND PERMEABILITY: Well drained, low to medium runoff, slow permeability.
MLRA OFFICE RESPONSIBLE: Lakewood, Colorado
USE AND VEGETATION: These soils are used mainly for rangeland and wildlife habitat. The potential native vegetation is dominantly shadscale, Castle Valley saltbush, galleta, snakeweed, mat saltbush, spiny horsebush, pricklypear, and bottlebrush squirreltail. This soil has been correlated to the Desert Alkali Bench (Castle Valley Saltbush) - 034XY101UT range site at the type location in Utah.
DISTRIBUTION AND EXTENT: Eastern Utah. LRR D, MLRA 34. This series is of small extent.
SERIES ESTABLISHED: Grand County, Utah-Central Part, 1982.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: The zone from 0 to 2 inches. (E horizon)
Natric horizon: The zone from 2 to 16 inches. (Btn and Btkn horizons)
Calcic horizon: The zone from 7 to 60 inches. (Btkn, Bk1, Bk2, and 2Bky horizons)
Lithologic discontinuity: The presence of loamy-skeletal materials starting at the upper boundary of the 2Bky horizon.
ADDITIONAL NOTES: Taxonomic Version: Eighth Edition, 1998.
The CEC clay activity class was inferred from laboratory data in the Uintah Area Soil Survey.
Leeko in Grand County where this series was established is outside the range of the series control section for the Leeko series. It has a loamy substratum, warmer MAAT (51 to 55 degrees) and a longer FFP (140 to 170 days).