LOCATION TUCANNON WAEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Pachic Haploxerolls
TYPICAL PEDON: Tucannon silt loam - grassland on a 20 percent southeast slopes between gently sloping upland and steep canyon wall; 2,300 feet above sea level. (Colors are for moist soil unless stated otherwise).
A1--0 to 3 inches; very dark brown (10YR 2/2) silt loam, dark grayish brown (10YR 4/2) dry; moderate fine and medium granular structure; slightly hard, friable, slightly sticky, nonplastic; many fine roots; common fine interstitial pores; slightly acid (pH 6.2); abrupt wavy boundary. (2 to 10 inches thick)
A2--3 to 11 inches; very dark brown (10YR 2/2) silt loam, dark grayish brown (10YR 4/2) dry; weak fine and medium granular structure; slightly hard, friable, sticky slightly plastic; common fine and very fine roots; common very fine pores; slightly acid (pH 6.4); clear wavy boundary. (4 to 8 inches thick)
AB--11 to 17 inches; very dark grayish brown (10YR 3/2) heavy silt loam, grayish brown (10YR 5/2) dry; weak medium prismatic structure that parts to moderate fine blocky structure; hard, friable, sticky, plastic; fine roots; common very fine pores; few very thin coatings, which may be clay films, on some surfaces of peds; neutral (pH 6.6); gradual wavy boundary. (4 to 18 inches thick)
Bw--17 to 23 inches; dark brown (10YR 3/3) silt loam, brown (10YR 5/3) dry; weak medium prismatic structure; slightly hard, friable, slightly sticky, slightly plastic; few fine roots; many fine pores; neutral (pH 6.8); clear wavy boundary. (4 to 6 inches thick)
BC--23 to 28 inches; brown (10YR 4/3) silt loam, pale brown (10YR 6/3) dry; weak coarse prismatic structure; slightly hard, friable, slightly sticky, slightly plastic; few fine roots; common fine pores; neutral (pH 6.8); abrupt wavy boundary. (0 to 6 inches thick)
2R--28 inches; basalt.
TYPE LOCATION: Columbia County, Washington; 1/2 mile northeast of gravel pile on Highway 3L and 175 feet southeast of road; NE1/4NE1/4 sec. 26, T. 11 N., R. 40 E.
RANGE IN CHARACTERISTICS: The solum thickness and depth to a lithic contact is 20 to 40 inches. Mean annual soil temperature is 47 to 54 degrees F. The soils are usually moist but are dry for 75 to 90 consecutive days in all parts between depths of 4 and 12 inches during summer and fall of most years. The mollic epipedon is 20 to 30 inches thick. The particle-size control section averages 18 to about 25 percent clay, and less than 15 percent coarser than very fine sand. The soils are neutral or slightly acid.
The A horizon has value of 4 or 5 dry, and chroma of 1 or 2 moist and dry.
The AB horizon has value of 4 or 5 dry, 2 or 3 moist, and chroma of 2 or 3 moist and dry.
The Bw horizon has value of 4 or 5 dry.
The BC horizon has value of 5 or 6 dry, 3 or 4 moist, and chroma of 3 or 4. Basalt pebbles range from 0 to 20 percent.
COMPETING SERIES: These are the Athena and La Grande series. Athena and La Grande soils are deeper than 40 inches.
GEOGRAPHIC SETTING: Tucannon soils are on benches and plateaus and are in the channeled scablands. These soils formed in loess and minor amounts of volcanic ash. Slopes are 0 to 65 percent. The climate is characterized by warm, dry summers and cool, moist winters. The average annual precipitation ranges from 15 to 19 inches. The mean January temperature is about 31 degrees F, the mean July temperature is about 70 degrees F, and the mean annual temperature is about 50 degrees F. The frost-free season is 110 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Athena soils and the Gwin, Mondovi, Patit Creek, and Waha soils. Gwin soils are underlain by bedrock at a depth of 10 to 20 inches, and are loamy-skeletal. Mondovi and Patit Creek soils are deep and have organic matter content that decreases irregularly with depth. Waha soils are fine-loamy and have an argillic horizon.
DRAINAGE AND PERMEABILITY: Well-drained; slow to rapid runoff; moderate permeability.
USE AND VEGETATION: Used largely for grazing and for dryland cropland. Wheat, barley, peas, lentils, hay, and pasture are common crops. Vegetation is mainly Idaho fescue and bluebunch wheatgrass, with some lupine, balsamroot, and potentilla.
DISTRIBUTION AND EXTENT: Southeastern Washington, possibly eastern Oregon and northern Idaho.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Columbia County (Columbia County Area), 1971.
ADDITIONAL DATA: S61Wash-7-1-(1-4), Riverside Lab Nos. 6 1137-61140.