LOCATION TEZUMA UTEstablished Series
TAXONOMIC CLASS: Fine-silty over clayey, mixed, superactive, calcareous, mesic Typic Torrifluvents
TYPICAL PEDON: Tezuma silt loam - rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 4 inches; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; moderate thin platy structure that parts to fine granular; hard, firm, sticky and plastic; few medium and few fine roots; 1/2 inch thick crust with vesicular pores; many fine and very fine pores below 1/2 inch; moderately calcareous; very strongly alkaline (pH 9.8); clear wavy boundary. (2 to 5 inches thick)
C1--4 to 18 inches; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; weak thin platy structure that parts to weak fine granular; slightly hard, very friable, slightly sticky and plastic; few fine roots; common fine and very fine pores; moderately calcareous; strongly alkaline (pH 9.0); clear wavy boundary. (12 to 16 inches thick)
C2--18 to 48 inches; pinkish gray (7.5YR 6/2) silty clay, brown (7.5YR 4/2) moist; massive; very hard, very firm, sticky and very plastic; few fine roots; common fine and very fine pores; moderately calcareous; strongly alkaline (pH 8.5).
TYPE LOCATION: San Juan County, Utah. About l mile north of Hatch Trading Post. 2000 feet north and 1000 feet west of the SE corner of section 13, T.38 S., R.25 E., S.L.B. & M.
RANGE IN CHARACTERISTICS:
Soil moisture: The soils are dry more than 1/2 of the time the soil temperature is above 41 F., and are not moist in the moisture control section for 1/2 of the time the soil temperature is above 41 degrees F. Typic aridic moisture regime.
Mean annual soil temperature: 54 to 58 degrees F.
Mean summer soil temperature at 20 inches: 74 to 79 degrees F.
Organic matter content: decreases irregularly with depth.
A horizons
Hue: 10YR
Value: 5 and 6 dry, 4 and 5 moist
Chroma: 2 and 3
Reaction: strongly to very strongly alkaline.
C horizons
Hue: 10YR and 7.5YR
Value: 5 and 6 dry and 4 and 5 moist
Chroma: 2 and 3
Texture in the control section: dominantly silty clay and averages more than 35 percent clay but has strata of silt loam
Reaction: moderately to strongly alkaline.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Tezuma soils occur on nearly level to gently sloping narrow flood plains of intermittent streams. Slopes are 0 to 3 percent. The climate is semiarid. These soils have formed in mixed alluvium. The mean annual temperature is about 55 degrees F. and the mean summer temperature is about 78 degrees F. The average annual precipitation is 6 to 8 inches. Frost-free period is about 150 to 180 days. Elevation ranges from 4500 to 4800 feet.
GEOGRAPHICALLY ASSOCIATED SOILS: Tezuma soils are nearly always surrounded by Badland. They are most closely associated with Tohona and Whit soils. Tohona soils have a gypsic horizon and the texture of the control section averages sandy clay loam. Whit soils have a calcic horizon and the texture of the control section averages very fine sandy loam.
DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderately slow to slow and runoff is rapid to moderate.
USE AND VEGETATION: Used only for rangeland. Vegetation is dominantly greasewood.
DISTRIBUTION AND EXTENT: Southeastern Utah and probably northern Arizona. This series is inextensive. MLRA 35.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: 1976
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from 0 to 9 inches (A horizon)
Entisol feature - The absence of diagnostic subsurface horizons
Fluvent feature - Organic matter content decreases irregularly with depth
Classified according to Soil Taxonomy, Second Edition, 1999; Keys to Soil Taxonomy Tenth Edition, 2006.
The Tezuma soils were formerly classified in the Alluvial soils great soil group.