LOCATION IRIS OREstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Duridic Haploxerolls
TYPICAL PEDON: Iris silt loam - cropland, on nearly level plain at 2290 feet elevation. (When described (10/11/89), the soil was dry throughout. The colors are for dry soil unless otherwise noted.)
Ap--0 to 4 inches: brown (10YR 5/3) silt loam, very dark grayish brown (10YR 3/2) moist; massive; slightly hard, very friable, slightly sticky and slightly plastic; few very fine roots; many very fine interstitial pores; neutral (pH 7.2); clear smooth boundary.
A--4 to 14 inches: brown (10YR 5/3) silt loam, very dark grayish brown (10YR 3/2) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few fine roots; many very fine interstitial pores; neutral (pH 7.2); clear smooth boundary. (Combined thickness of the A horizon is 10 to 18 inches)
Bw--14 to 34 inches: pale brown (10YR 6/3) silt loam, dark brown (10YR 3/3) moist; weak medium subangular blocky structure; slightly hard, very friable, sticky and slightly plastic; few very fine roots; many very fine tubular pores; mildly alkaline (pH 7.6); clear wavy boundary. ( 15 to 24 inches thick.)
Bkq--34 to 60 inches: pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; massive; hard, firm and brittle, slightly sticky and nonplastic; many very fine tubular pores; slightly effervescent; mildly alkaline (pH 7.6).
TYPE LOCATION: Jefferson County, Oregon; 1.2 miles west of Culver; 700 feet south and 100 feet east of the northwest corner of the southeast quarter of section 24, T. 12 S., R. 12 E. (Latitude 44 degrees, 30 minutes, 54 seconds N, Longitude 121 degrees, 14 minutes, 16 seconds W)
RANGE IN CHARACTERISTICS: The depth to bedrock is 60 inches or more. The soil moisture control section is usually dry and is dry in all parts for 120 to 150 days (cumulative) following the summer solstice. The mean annual soil temperature is 48 to 54 degrees F. The profile contains 10 to 30 percent volcanic glass and glass-coated aggregates. Depth to carbonates and the hard brittle layer is 30 to 40 inches. The mollic epipedon is 10 to 15 inches thick. Base saturation is 80 to 100 percent. The particle-size control section is silt loam and averages 18 to 22 percent clay and 65 to 75 percent silt and very fine sand.
The A horizon hue of 10YR, value of 5 dry and 3 moist, and chroma of 2 or 3 moist and dry. It is neutral.
The Bw horizon has hue of 10YR, value of 6 dry and 3 moist, and chroma of 2 or 3 moist and dry. It is neutral or mildly alkaline.
The Bkq horizon has hue of 10YR, value of 6 dry, 3 or 4 moist, and chroma of 2 or 3 moist and dry.
COMPETING SERIES: This is the Caniwe series. Caniwe soils contain 25 to 60 percent durinodes in a non-brittle matrix, and the depth to the 2Cq layer containing the durinodes is 14 to 26 inches.
GEOGRAPHIC SETTING: Iris soils are in old lake basins on terraces and plateaus. Slopes are 0 to 1 percent. These soils formed in alluvium from volcanic ash and loess. The climate is characterized by cool, moist winters and hot, dry summers. Elevations range from 2,000 to 2,500 feet. The mean annual precipitation is 8 to 11 inches. The mean annual temperature is 47 to 52 degrees F. The frost-free period is 110 to 140 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Madras. Cullius, and Agency soils on adjacent terraces and plateaus. Cullius soils are shallow over bedrock. Madras and Agency soils are moderately deep over bedrock.
DRAINAGE AND PERMEABILITY: Well drained; moderately slow permeability.
USE AND VEGETATION: These soils are used for irrigated cropland.
DISTRIBUTION AND EXTENT: Terraces and plateaus of Central Oregon; MLRA 10. The series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Jefferson County (Upper Deschutes River Area), Oregon, 1992.
REMARKS: Diagnostic horizons and features in this pedon:
mollic epipedon - from the soil surface to 14 inches. (Ap and A horizons)
cambic horizon - from 14 to 34 inches. (Bw horizon)
duric layer - from 34 to 60 inches. (Bkq horizon)
ADDITIONAL DATA: Partial laboratory data is available for this soil. Reference sample S89OR-031-012 from Jefferson County, Oregon, NSSL, Lincoln, NE, 5/90.