LOCATION OWYHEE ID+OREstablished Series
TAXONOMIC CLASS: Coarse-silty, mixed, superactive, mesic Xeric Haplocambids
TYPICAL PEDON: Owyhee silt loam, cultivated. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 10 inches; light brownish gray (10YR 6/2) light silt loam, dark grayish brown (10YR 4/2) moist; very weak very fine granular structure; weak thin platy in upper part; slightly hard, very friable, slightly sticky and slightly plastic; common fine roots; few very fine vesicular and tubular pores; moderately alkaline (pH 8.2); abrupt smooth boundary. (0 to 10 inches thick)
Bw--10 to 22 inches; light brownish gray (10YR 6/2) light silt loam, dark grayish brown (10YR 4/2) moist; weak medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common fine roots; common very fine tubular pores; moderately alkaline (pH 8.2); abrupt smooth boundary. (6 to 14 inches thick)
Bkq--22 to 44 inches; white (10YR 8/2) silt loam, light brownish gray (2.5Y 6/2) moist; laminated lacustrine sediments in weak medium plates that part to weak fine and medium angular and subangular blocky; hard, friable, slightly sticky and slightly plastic; few very fine and fine roots; common very fine tubular pores; strongly effervescent; moderately alkaline (pH 8.3); gradual smooth boundary. (12 to 26 inches thick)
C--44 to 60 inches; light gray (10YR 7/2) silt loam, brown (10YR 5/3) moist; laminated lacustrine sediments in strong medium and thick plates, that part to moderate, fine and medium angular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots and pores; slightly effervescent; moderately alkaline (pH 8.3). (one to many feet thick)
TYPE LOCATION: Canyon County, Idaho; about one mile northeast of Wilder in a terrace having less than 1 percent slope and elevation of 2,418 feet; 1,300 feet south and 100 feet west of the northeast corner of sec. 14, T.4N., R.5W.
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 51 to 54 degrees F.
Average summer soil temperature - 69 to 72 degrees F.
Depth to Laminae - 20 to 35 inches
Depth to carbonates - 12 to 24 inches
A horizon
Value - 6 or 7 dry, 4 or 5 moist
Chroma - 2 or 3 dry or moist
Reaction - neutral to moderately alkaline
Bw horizon
Structure - weak subangular blocky or prismatic
Bkq and C horizons
Most pedon horizons contains - few or common hard, firm, rounded nodules of soil material or (Cicada) krotovinas 0.5 to 0.8 inches in diameter. In the upper few laminae, discontinuous, sporadic or minor cementation or glazing that is very weak, extremely thin (less than 1mm), dense brittle calcium carbonate and/or silica crust. It does not prevent roots downward extension across the entire pedon.
Some pedons stains or concretions - few, fine black (manganese) in the lower part of the Ck horizon or upper part of the laminae.
COMPETING SERIES: These are the Barrymore (T), Sagemoor, Shano, Stingal, Wacota, and Warden series. Barrymore soils are moderately deep. Sagemoor soils lack a calcic horizon. Shano soils lack laminated layers above depth of 40 inches. Stingal soils have calcareous A and B horizons and lack laminated lacustrine sediments in the series control section. Wacota soils lack a calcic horizon. Warden soils lack a calcic horizon and laminated silt loam above depth of 40 inches.
GEOGRAPHIC SETTING: The soils are in level to sloping undulating, or slightly depressed areas in low and medium terraces at elevations of 2,000 to 4,500 feet. Slopes most commonly are less than 3 percent but range from 0 to 30 percent. The soils formed in moderately calcareous, laminated, medium textured, lacustrine material or old alluvium over these laminated sediments. The climate is semiarid and has dry summers. Average freeze-free period is 110 to 170 days, and average annual precipitation is 7 to 12 inches, including about 1 to 3 feet of snow. Average annual temperature is 49 to 52 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bramwell, Greenleaf, Nyssa, Nyssaton and Power soils. Bramwell soils are usually moist above depth of 40 inches. Nyssa soils have duripans. Power and Greenleaf soils have Bt horizons. Nyssaton soils are calcareous throughout the profile.
DRAINAGE AND PERMEABILITY: Well-drained; slow to medium runoff; moderate permeability in the upper part and moderately slow or slow permeability in the laminated sediments.
USE AND VEGETATION: Mostly irrigated cropland. The principal crops are corn, small grains, sugar beets, potatoes, hops, alfalfa, pasture grasses, and onions. The vegetation on uncultivated areas is big sagebrush, Sandberg bluegrass, bluebunch wheatgrass, cheatgrass, basin wildrye, and annual weeds and grasses.
DISTRIBUTION AND EXTENT: Valleys in southwestern Idaho and eastern Oregon. The series is of moderately extensive.
MLRA OFFICE RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Payette County, Idaho, 1971.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - zone from 0 to 10 inches (Ap horizon)
Cambic horizon - Zone from 10 to 22 inches (Bw Horizon)
Calcic horizon - Zone from 22 to 44 inches (Bkq horizon)