LOCATION OPIE OREstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, calcareous, frigid Cumulic Endoaquolls
TYPICAL PEDON: Opie silt loam on a 1 percent slope in rangeland at an elevation of 4140 feet. (Colors are for dry soil unless otherwise noted).
A1--0 to 7 inches; gray (10YR 5/1) silt loam, very dark gray (10YR 3/1) moist; weak fine platy structure in the upper 2 inches, moderate medium prismatic structure in the lower 5 inches; hard, firm, slightly sticky and slightly plastic; many fine roots; many very fine tubular pores; slightly effervescent with disseminated lime; very strongly alkaline (pH 9.4); gradual smooth boundary.
A2--7 to 10 inches; gray (10YR 5/1) silty clay loam, black (10YR 2/1) moist; moderate fine prismatic structure; slightly hard, friable, slightly sticky and slightly plastic; many fine roots; many very fine tubular pores; slightly effervescent with disseminated lime; very strongly alkaline (pH 9.4); clear abrupt boundary.
A3--10 to 16 inches; gray (10YR 5/1) silt loam, black (10YR 2/1) moist; moderate fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many fine roots; many very fine tubular pores; strongly effervescent with disseminated lime; strongly alkaline (pH 9.0); clear smooth boundary.
A4--16 to 26 inches; dark gray (10YR 4/1) silty clay loam, black (10YR 2/1) moist; weak fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; many fine roots; many very fine tubular pores; strongly effervescent with disseminated lime; strongly alkaline (pH 9.0); clear wavy boundary. (The combined thickness of the A horizon is 24 to 40 inches thick.)
Ak1--26 to 34 inches; gray (10YR 6/1) silt loam, very dark gray (10YR 3/1) moist; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many fine roots; many very fine tubular pores; strongly effervescent with disseminated lime and many pale brown flecks and streaks of soft powdery segregated lime; common fine distinct reddish brown (5YR 5/4) moist iron accumulations; strongly alkaline (pH 9.0); abrupt wavy boundary.
Ak2--34 to 44 inches; dark grayish brown (10YR 4/2) silt loam, very dark brown (10YR 2/2) moist; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many fine roots; many very fine tubular pores; strongly effervescent with disseminated lime and many pale brown flecks and streaks of soft powdery segregated lime; common fine distinct reddish brown (5YR 5/4) moist iron accumulations; strongly alkaline (pH 9.0); abrupt wavy boundary. (The combined thickness of the Ak horizon is 16 to 25 inches)
2C--44 to 64 inches; light brownish gray (10YR 6/2) gravelly loam, dark grayish brown (10YR 4/2) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few roots; common fine distinct reddish brown (5YR 5/4) moist iron accumulations; 20 percent gravel; moderately alkaline (pH 8.2).
TYPE LOCATION: Harney County, Oregon; about 3.5 miles east of the town of Burns about 3000 feet west and 3300 feet south of the northeast corner of sec. 14, T. 23 S., R. 31 E.; Poison Creek Slough quadrangle; lat. 43 degrees 34 minutes 36 seconds N. and long. 119 degrees 58 minutes 15 seconds W., NAD 1927.
RANGE IN CHARACTERISTICS: The thickness of the mollic epipedon and depth to segregated carbonates is 24 to 40 inches. The mean annual soil temperature is 45 to 47 degrees F.. The particle-size control section averages 18 to 35 percent clay and less than 15 percent material coarser than fine sand. The soils are calcareous and strongly or very strongly alkaline throughout the A and Ak horizons. The mollic epipedon has 1 to 4 percent organic matter throughout. Depth to the gravelly substratum is 40 to 60 inches.
The A horizon has SAR of 2 to 10 and EC of 8 to 30. The EC values are highest at the surface. It is silt loam or silty clay loam.
The C horizon has a value 6 or 7 dry and chroma of 2 moist and 2 or 3 dry. It is gravelly loam, gravelly sandy loam, loamy sand, and gravelly loamy sand. It has 10 to 30 percent gravel and 5 to 15 percent clay.
COMPETING SERIES: These are the Bigstone, Halleck, Homefield, Inkom, Lamoure, Playmoor and Rauville series. All soils except for Homefield are slightly or moderately alkaline. In addition, Bigstone and Lamoure soils are on glacial landscapes and have carbonates at 0 to 10 inches. Homefield soils have over 10 percent organic matter throughout the particle-size control section. Playmoor soils have accumulations of salt, carbonates and gypsum.
GEOGRAPHIC SETTING: Opie soils are on low stream terraces formed in alluvium. Slopes are 0 to 2 percent. Elevation is 4000 to 4500 feet. The climate is characterized by hot dry summers and cold moist winters. The mean annual precipitation is 6 to 12 inches. The mean annual air temperature is 43 to 45 degrees F. The frost-free period is 50 to 80 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Skidoosprings, Crowcamp, Fury, Voltage, and Widowspring soils. Skidoosprings soils are on adjacent higher lake terraces, are coarse-loamy and have an ochric epipedon. Crowcamp soils are on higher lake terraces, are in a fine textural family and have an argillic horizon. Fury soils are on adjacent lower stream terraces and are non saline-alkaline. Voltage soils are on higher lake terraces, are coarse-loamy and have a calcic horizon. Widowspring soils are on higher stream terraces and are non saline-alkaline.
DRAINAGE AND PERMEABILITY: Poorly drained; ponded; moderately slow permeability. Watertable depth is from 0.5 feet above the surface to 2.5 feet below the surface from March through July. Ponding is frequent. Flooding is rare.
USE AND VEGETATION: The soils are used for meadow hay and livestock grazing. Vegetation mainly is alkalai sacaton, inland saltgrass, alkalai bluegrass, and alkalai cordgrass.
DISTRIBUTION AND EXTENT: Basins of southeastern Oregon; MLRA 23. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Harney County, Oregon 1997.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon: from 0 to 26 inches (A1, A2, A3, and A4 horizons)
Aquoll: Chroma of 1 in the lower part of mollic epipedon (16 to 26 inches) and chroma of 1 in matrix immediately below mollic epipedon with hue of 10YR and distinct 5YR 5/4 redox concentrations.
Soil is calcareous from the surface to 44 inches.
Particle-size control section: from 10 to 40 inches (A3, A4, Ak1, and Ak2 horizons) silt loam and silty clay loam textures.