LOCATION ZOLTAY COEstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Pachic Argiustolls
TYPICAL PEDON: Zoltay loam, in grassland. (Colors are for dry soil unless otherwise noted.)
A--0 to 8 inches; dark grayish brown (10YR 4/2) clay loam, very dark brown (10YR 2/2) moist; weak medium subangular blocky structure parting to moderate fine granular; soft, very friable, slightly sticky and slightly plastic; 10 percent sandstone fragments; slightly alkaline; clear smooth boundary. (6 to 14 inches thick)
BAt--8 to 13 inches; dark grayish brown (10YR 4/2) clay loam, very dark grayish brown (10YR 3/2) moist; moderate medium subangular blocky structure parting to moderate medium granular; slightly hard, friable, moderately sticky and moderately plastic; few faint clay films on faces of peds and in root channels; 10 percent sandstone fragments; slightly alkaline; clear smooth boundary. (2 to 6 inches thick)
Bt--13 to 22 inches; brown (10YR 5/3) cobbly clay loam, dark brown (10YR 3/3) moist; strong medium subangular blocky structure parting to moderate fine angular blocky; hard, firm, moderately sticky and moderately plastic; common prominent clay films on faces of peds; 20 percent sandstone cobbles; moderately alkaline; clear wavy boundary. (6 to 24 inches thick)
Bk1--22 to 31 inches; pale brown (10YR 6/3) cobbly clay loam, brown (10YR 5/3) moist; moderate medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; 30 percent sandstone cobbles; distinct fine and medium seams and soft masses of calcium carbonate; strongly effervescent; moderately alkaline; gradual wavy boundary.
Bk2--31 to 40 inches; very pale brown (10YR 7/3) cobbly clay loam, pale brown (10YR 6/3) moist; massive; hard, friable, moderately sticky and moderately plastic; 30 percent sandstone cobbles; common medium and large seams of calcium carbonate; violently effervescent; moderately alkaline; gradual smooth boundary. (combined thickness of the Bk1 and Bk2 horizons is 16 to 36 inches thick)
Bk3--40 to 60 inches; very pale brown (10YR 7/3) cobbly loam, pale brown (10YR 6/3) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; 25 percent sandstone cobbles, 10 percent stones; disseminated and few faint soft masses of calcium carbonate; violently effervescent; moderately alkaline.
TYPE LOCATION: Rio Blanco County, Colorado; about 3 miles southeast of Meeker; located about 2,025 feet west and 650 feet north of the southeast corner of Sec. 6, T. 1 S., R. 93 W.; Veach Gulch USGS quad; lat. 39 degrees 59 minutes 36 seconds N. and long. 107 degrees 52 minutes 23 seconds W., NAD 27
RANGE IN CHARACTERISTICS:
Soil moisture regime: ustic; typic ustic subclass. The smcs is dry in most parts for 120 days following the winter solstice, and moist in some part for at least 30 cumulative days from August 1 through October 15.
Mean annual soil temperature: 42 to 46 degrees F.
Mean summer soil temperature: 59 to 63 degrees F.
Thickness of the mollic epipedon: 16 to 40 inches
Depth to uniformly calcareous material: 10 to 40 inches
Depth to secondary calcium carbonate: 15 to 40 inches
Linear extensibility: 4.0 to 6.0 cm (estimated)
Particle-size control section:
Clay content: 35 to 50 percent, and 5 to 40 percent silt Rock fragment content: 5 to 35 percent, mainly gravel and cobble.
A horizon:
Hue: 7.5YR to 5Y
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 1 to 3, dry and moist
Texture, fine earth fraction: L, SIL, CL
Rock fragment content: 0 to 35 percent
Reaction: neutral to moderately alkaline
Bt horizon:
Hue: 7.5YR to 5Y
Value: 3 to 7 dry, 3 to 6 moist
Chroma: 1 to 6, dry and moist
Texture, fine earth fraction: CL, C
Rock fragment content: 5 to 35 percent
Calcium carbonate equivalent: 0 to 5 percent
Reaction: neutral to moderately alkaline
Bk horizon:
Hue: 7.5YR to 5Y
Value: 5 to 7 dry, 4 to 6 moist
Chroma: 3 to 6, dry and moist
Texture, fine earth fraction: L, CL, C
Rock fragment content: 5 to 55 percent
Calcium carbonate equivalent: 3 to 15 percent
Reaction: slightly alkaline to strongly alkaline
COMPETING SERIES: These are the:
Chivington,
Fughes,
Hillery,
Kubler, and
Zeeland series.
In addition, the following soils may be competitors when the classification is updated:
Savar series.
Chivington: have peak periods of precipitation in the spring and early summer.
Fughes: are noncalcareous to depths of more than 40 inches.
Hillery and Kubler: have hue of 5YR or redder.
Savar: have Bt horizons that are 35 to more than 60 inches thick, and have peak periods of precipitation in the spring and early summer.
Zeeland: have less than 10 percent rock fragments that are mostly gravel, and formed in glacial till on till plains.
GEOGRAPHIC SETTING:
Parent material: alluvium derived from sedimentary rocks
Landform: alluvial fans, terraces, and valley sideslopes
Slopes: 1 to 25 percent
Elevation: 6,000 to 8,500 feet
Mean annual air temperature: 41 to 45 degrees F.
Mean annual precipitation: 16 to 19 inches.
Wettest months: monthly precipitation is fairly uniform throughout the year with a slight decline in June and winter months.
Driest months: June
Frost-free period: 70 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Ricot and
Tridell soils.
Ricot soils have a mollic epipedon less than 16 inches thick and contain less than 15 percent rock fragments throughout.
Tridell soils are skeletal.
DRAINAGE AND PERMEABILITY: Well drained; medium or high runoff; slow permeability.
USE AND VEGETATION: These soils are used for hay crops, dryland small grains, pasture, rangeland for cattle and sheep, and wildlife habitat. Native vegetation is mainly big sagebrush, Gambel's oak, serviceberry, native bluegrasses, western wheatgrass, Arizona fescue, and Columbia needlegrass.
DISTRIBUTION AND EXTENT: Western Colorado. LRR E, MLRA 48A. This series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Rio Blanco County, Rifle Area, Colorado, 1977. Series proposed Rio Blanco County, 1972. The name is coined.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon (Pachic feature): The zone from 0 to 22 inches. (A, BAt, and Bt horizons)
Argillic horizon: The zone from 8 to 22 inches. (BAt and Bt horizons)
Particle size control section: The zone from 8 to 22 inches. (BAt and Bt horizons)
Keys to Soil Taxonomy: Classified according to the Eighth Edition, 1998