LOCATION TRIO IDEstablished Series
TAXONOMIC CLASS: Loamy, mixed, superactive, mesic, shallow Xereptic Haplodurids
TYPICAL PEDON: Trio very fine sandy loam, cropland. (Colors are for dry soil unless otherwise noted.)
Ap1--0 to 3 inches; pale brown (10YR 6/3) very fine sandy loam, dark yellowish brown (10YR 4/4) moist; weak very thin platy structure; slightly hard, friable; few very fine and fine roots; few very fine and fine pores; neutral (pH 7.0); clear smooth boundary. (0 to 3 inches thick)
Ap2--3 to 9 inches; pale brown (10YR 6/3) very fine sandy loam, dark yellowish brown (10YR 4/4) moist; weak fine subangular blocky structure; slightly hard, friable; few very fine and fine roots; few very fine and fine tubular pores; mildly alkaline (pH 7.5); clear smooth boundary. (5 to 9 inches thick)
B2--9 to 14 inches thick; pale brown (10YR 6/3) very fine sandy loam, dark yellowish brown (10YR 4/4) moist; weak medium subangular blocky structure; slightly hard, friable, few very fine and fine roots; common very fine and fine tubular pores; mildly alkaline (pH 7.8); abrupt smooth boundary. (5 to 8 inches thick)
C1sicam--14 to 26 inches; light gray (10YR 7/2) duripan, pale brown (10YR 6/3) moist; massive; very hard, very firm; thin continuous, opalized surface which is covered by a root mat; weakly cemented matrix which is brittle when wet; about 40 percent durinodes; strongly calcareous; strongly alkaline (pH 8.6); clear wavy boundary. (8 to 20 inches thick)
C2ca--26 to 33 inches; very pale brown (10YR 7/3) very fine sandy loam, brown (10YR 5/3) moist; massive; slightly hard, friable; few very fine and fine tubular pores; about 10 percent durinodes; about 5 percent subrounded basalt gravel; slightly calcareous with common fine strongly calcareous lime veins; moderately alkaline (pH 8.4). (0 to 8 inches)
R--33 inches; highly jointed and fractured vesicular basalt.
TYPE LOCATION: Ada County, Idaho; about 2 1/2 miles southeast of Swan Falls Dam; approximately 415 feet north and 425 feet west of the SE corner of section 28, T.2S., R.1E.
RANGE IN CHARACTERISTICS: Depth to the duripan ranges from 10 to 20 inches. The mean annual soil temperature is 52 to 56 degrees F. Depth to bedrock is 20 to 40 inches. Cobbles and stones range from 0 to 5 percent above the duripan and 0 to 8 percent between the pan and bedrock.
The Ap and A1 horizons have chroma of 3 or 4.
The B horizon has chroma of 3 or 4. It is very fine sandy loam, silt loam or loam.
Some pedons have a thin moderately or strongly calcareous Cca horizon above the duripan. When this horizon is present, it has value of 6 or 7 dry, 4 through 6 moist, and chroma of 3 or 4. It is very fine sandy loam or loam.
The Ccasim horizon is weakly or strongly cemented.
The Cca horizon below the duripan is absent in some pedons. When this occurs, the pan rests directly on the bedrock.
COMPETING SERIES: This is the Shabliss series which lacks bedrock at a depth of less than 60 inches.
GEOGRAPHIC SETTING: Trio soils are on basalt plains. Elevations are 2,700 to 3,500 feet. Slopes are 0 to 8 percent. The soils formed in a veneer of wind modified alluvium with a strong loess influence. The climate is middle latitude steppe (Trewartha's Modified Koppen System), with cool moist winters and dry summers. The mean annual precipitation ranges from 8 to 10 inches. The mean January temperature is about 32 degrees F.; the mean July temperature is about 72 degrees F.; and the mean annual temperature is 50 to 54 degrees F. The frost free season is 140 to 160 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Garbutt, Minidoka, Scism, Trevino, Truesdale and Turbyfill soils and the competing Shabliss soil. Garbutt and Turbyfill soils lack a duripan. Minidoka, Scism and Truesdale soils have a duripan at a depth of 20 to 40 inches. Trevino soils lack a duripan and have bedrock above a depth of 20 inches.
DRAINAGE AND PERMEABILITY: Well drained; very slow to medium runoff; moderate permeability above and very slow permeability below through the duripan.
USE AND VEGETATION: The soils are used dominantly for range and lesser extent for irrigated cropland. Irrigated crops include alfalfa, small grains, corn, potatoes and sugar beets. Vegetation is mainly big sagebrush (Wyomingensis), spiny hopsage, winterfat, Indian ricegrass, Sandberg bluegrass and annual brome.
DISTRIBUTION AND EXTENT: Southwestern Idaho and possibly adjoining areas. The series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Ada County, Idaho, 1977.