LOCATION TOMASAKI UT
Established Series
Rev. DAL-RLT
01/2023
TOMASAKI SERIES
The Tomasaki series consists of very deep, well drained, slowly permeable soils that formed in alluvium derived dominantly from diorite. These soils are on glacial outwash fans at elevations of 7,800 to 9,200 feet. Slopes are 0 to 65 percent. Average annual precipitation is about 20 inches; and the mean annual temperature is about 41 degrees F.
TAXONOMIC CLASS: Fine, smectitic, frigid Vertic Argiustolls
TYPICAL PEDON: Tomasaki loam - woodland. (Colors are for air-dry soil unless otherwise stated.)
A--0 to 11 inches; dark brown (7.5YR 4/2) loam, dark brown (7.5YR 3/2) moist; weak medium prismatic structure parting to moderate medium subangular blocky; hard, firm, slightly sticky; common very fine, few medium and coarse roots; common very fine, few fine pores; 5 percent pebbles; neutral (pH 6.6); clear wavy boundary. (11 to 15 inches thick)
Bt1--11 to 17 inches; yellowish red (5YR 5/6) clay, yellowish red (5YR 4/6) moist; moderate medium subangular blocky structure; extremely hard, extremely firm, sticky and plastic; few very fine, medium and coarse, common fine roots; few very fine and fine pores; many moderately thick clay films on faces of peds; 5 to 10 percent pebbles; neutral (pH 6.6); clear smooth boundary. (2 to 8 inches thick)
Bt2--17 to 24 inches; yellowish red (5YR 5/6) clay, yellowish red (5YR 4/6) moist; weak, fine prismatic structure parting to strong medium subangular blocky; extremely hard, extremely firm, sticky and plastic; few very fine, medium, coarse, and common fine roots; few very fine and fine pores; many moderately thick clay films on faces of peds; 5 to 10 percent pebbles; neutral (pH 6.6); gradual smooth boundary. (3 to 9 inches thick)
Bt3--24 to 34 inches; yellowish red (5YR 5/6) clay loam, yellowish red (5YR 4/6) moist; moderate medium subangular blocky structure; extremely hard, extremely firm, sticky and plastic; few very fine, fine, medium and coarse roots; few very fine and fine pores; many moderately thick clay films on faces of peds; 15 percent fine pebbles; neutral (pH 6.8); gradual wavy boundary. (8 to 12 inches thick)
2Bt4--34 to 50 inches; reddish brown (5YR 4/4) very cobbly clay
loam, yellowish red (5YR 4/6) moist; weak medium subangular blocky structure; extremely hard, extremely firm, sticky and plastic; few fine, medium and coarse roots; few very fine pores; many moderately thick clay films on faces of peds; 20 percent pebbles, 20 percent cobbles and 5 percent stones; neutral (pH 6.8); gradual wavy boundary. (0 to 20 inches thick)
2C--50 to 60 inches; light brown (7.5YR 6/4) cobbly clay loam, brown (7.5YR 5/4) moist; massive; extremely hard, extremely firm, slightly sticky and plastic; few fine roots; few very fine pores; 20 percent cobbles, 5 percent pebbles; neutral (pH 6.8).
TYPE LOCATION: Grand County, Utah about 7.5 miles east of Castleton, 20 feet south and 800 feet west of the northeast corner, sec. 32, T. 25 S., R. 25 E.
RANGE IN CHARACTERISTICS: The mollic epipedon is 11 to 15 inches thick. The argillic horizon extends to a depth of 40 to 60 inches. The mean annual soil temperature is 42 to 44 degrees F, and the mean summer soil temperature at a depth of 20 inches is 60 to 62 degrees F. These soils are moist in some part of the moisture control section more than half the time the soil temperature at 20 inches is higher than 41 degrees F. These soils are dry in some part of the moisture control section for more than 90 cumulative days in most years.
The A horizon has hue of 7.5YR or 10YR, value of 2 or 3 moist and chroma of 2 or 3 dry. It is neutral or mildly alkaline.
The Bt and 2Bt horizons have hue of 5YR or 7.5YR, value of 4 to 6 dry, 3 to 6 moist and chroma of 4 to 6 dry and moist. Textures are clay or clay loam in the Bt and cobbly clay loam, very cobbly clay loam or very cobbly clay in the 2Bt. The upper 20 inches of this horizon averages 35 to 45 percent clay and 0 to 15 percent rock fragments. It is neutral or mildly alkaline.
COMPETING SERIES: These are the
Absarokee,
Acree,
Bearpaw,
Brolliar, Danvars,
Delson,
Herm,
Mondamin,
Quilt,
Regent,
Ricot,
Wyola,
Tamaneen,
Tukuhnik, and
Work series. Absarokee, Acree, Bearpaw,
Danvers, Mondamin, Regent, Ricot, Wyola, Tamaneen, Tukuhnik, and Work soils have calcic horizons. Quilt soils have more than 15 percent rock fragments in the particle size control section and mean summer temperatures of 59 to 63 degrees F. Delson and Herm soils have argillic horizons less than 40 inches thick and lack clayey-skeletal material below 30 inches.
GEOGRAPHIC SETTING: Tomasaki soils are on glacial outwash fans and mountainslopes. Elevations range from 7,600 to 9,200 feet. These soils formed in colluvium and alluvium from diorite. Mean annual temperature is 39 to 42 degrees F, and the average annual precipitation is 17 to 25 inches. The freeze-free period is 60 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing
Herm and
Tukuhnik soils and the
Falcon,
Flygare,
Skylick and
Sligting soils. The Falcon soils have bedrock at 10 to 20 inches. Flygare, Skylick and Sligting soils have cryic temperature regimes.
DRAINAGE AND PERMEABILITY: Well drained; slow permeability; slow to rapid runoff.
USE AND VEGETATION: Used mainly for woodland, rangeland, and wildlife habitat. The potential vegetation is an overstory of ponderosa pine with an understory of muttongrass, elk sedge, bottlebrush squirreltail, snowberry, and Gambel oak.
DISTRIBUTION AND EXTENT: Southeastern Utah and western Colorado. The series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Canyonlands Area, Parts of Grand and San Juan Counties, Utah, 1983.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon -The zone from the surface to 11 inches (A
horizon).
Argillic horizon -The zone from 11 to 50 inches (Bt1, Bt2, Bt3,
2Bt horizons).
National Cooperative Soil Survey
U.S.A.