LOCATION TIROD IDEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Calcic Argixerolls
TYPICAL PEDON: Tirod silt loam in irrigated cropland on a 1 percent slope at 4,760 feet elevation. When described on May, 25 1979, the soil was moist below five inches. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 9 inches; grayish brown (10YR 5/2) silt loam, very dark grayish brown (10YR 3/2) moist; weak fine and medium subangular blocky structure parting to moderate fine granular; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine, and few medium and coarse roots; 5 percent gravel; neutral (pH 7.1); abrupt smooth boundary.
A--9 to 18 inches; grayish brown (10YR 5/2) silt loam, very dark grayish brown (10YR 3/2) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine, and few medium and coarse roots; 10 percent gravel; neutral (pH 7.2); abrupt wavy boundary. (Combined thickness of the A horizons is 9 to 19 inches)
Bt1--18 to 30 inches; light brownish gray (10YR 6/2) loam, dark brown (10YR 3/3) moist; moderate medium and coarse angular blocky structure; hard, firm, sticky and plastic; common very fine, few fine and medium roots; common distinct clay films in pores and on faces of peds; 10 percent gravel; neutral (pH 7.1); clear wavy boundary.
Bt2--30 to 40 inches; pale brown (10YR 6/3) clay loam, brown (10YR 4/3) moist; weak medium prismatic structure parting to moderate medium and coarse angular blocky; hard, firm, sticky and plastic; common very fine, few fine and medium roots; many distinct clay films in pores and on faces of peds; 10 percent gravel; neutral (pH 7.1); abrupt wavy boundary. (Combined thickness of the Bt horizons is 19 to 30 inches)
Bk--40 to 62 inches; very pale brown (10YR 8/2) loam, light yellowish brown (2.5Y 6/4) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few very fine, fine, and medium roots, 10 percent gravel; thin to moderately thick lime coatings on coarse fragments; common to many fine and medium irregular lime concretions in filaments; strongly effervescent; moderately alkaline (pH 7.9).
TYPE LOCATION: Oneida County, Idaho; about .75 miles north of Malad City, Idaho; 1,450 feet south and 30 feet east of the northwest corner of sec. 16, T. 14 S., R. 36 E. Latitude - 42 degrees, 12 minutes, 36 seconds North; Longitude - 112 degrees, 15 minutes, 24 seconds West.
RANGE IN CHARACTERISTICS:
Mollic epipedon - 10 to 19 inches thick
Thickness of argillic horizon - 19 to 30 inches
Depth to calcic horizon - 35 to 43 inches
Reaction of profile - neutral to moderately alkaline
Average annual soil temperature - 47 to 49 degrees F.
Particle-size control section
Clay content - averages 22 to 35 percent
Gravel content - averages 10 to 15 percent
A horizon
Hue - 10YR or 7.5YR
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 2 or 3 dry or moist
Bt horizon
Hue - 10YR or 7.5YR
Value - 4 through 6 dry, 3 or 4 moist
Chroma - 2 through 4 dry or moist
Texture - L, CL
Bk horizon
Hue - 10YR to 2.5Y
Value - 6 through 8 dry, 4 through 6 moist
Chroma - 2 through 4 dry or moist
Calcium carbonate equivalent - 15 to 25 percent
COMPETING SERIES: These are the Colockum, Hack, Polly, Pollynot (T) and Timpanogos soils. Colockum soils have average annual soil temperature greater than 49 degrees F. and lack a calcic horizon. Hack and Polly soils lack calcic horizons. Pollynot soils have an argillic horizon less than 19 inches thick. Timpanogos soils have less than 5 percent rock fragments in the particle-size control section.
GEOGRAPHIC SETTING: Tirod soils are on terraces and have slopes of 0 to 2 percent. Elevation ranges from 4,300 to 5,000 feet. The soil formed in alluvium from quartzite and lake sediments. Average annual precipitation is 12 to 14 inches and average annual air temperature is 45 to 47 degrees F. The frost free period is 100 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bingham, Kearns and Ladd soils. Bingham soils are moderately deep to sandy-skeletal material and are on concave terraces. Kearns soils lack an argillic horizon and are on slightly higher terraces. Ladd soils lack a calcic horizon and are on convex terraces.
DRAINAGE AND PERMEABILITY: Well drained; very slow to slow runoff; moderately slow permeability.
USE AND VEGETATION: Irrigated cropland. Used mostly for small grains and alfalfa.
DISTRIBUTION AND EXTENT: Southeastern Idaho. These soils are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Oneida County, Idaho, 1994.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the zone from the surface to 18 inches (the Ap and A horizons)
Argillic horizon - the zone from 18 to 40 inches (the Bt1 and Bt2 horizons)
Calcic horizon - the zone from 40 to 62 inches (the Bk horizon)
Particle-size control section - the upper 20 inches of the argillic horizon (the Bt1 and part of Bt2 horizons)