LOCATION MONDOVI WA+ID OREstablished Series
TAXONOMIC CLASS: Coarse-silty, mixed, superactive, mesic Cumulic Haploxerolls
TYPICAL PEDON: Mondovi silt loam-cultivated. (Colors are for moist soil unless otherwise stated)
Ap--0 to 10 inches; very dark brown (10YR 2/2) silt loam, dark grayish brown (10YR 4/2) dry; weak fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; many fine roots; slightly alkaline (pH 7.6); abrupt smooth boundary. (6 to 13 inches thick)
A1--10 to 33 inches; very dark brown (10YR 2/2) silt loam, dark grayish brown (10YR 4/2) dry; massive; slightly hard, friable, slightly sticky and slightly plastic; common fine and very fine roots; few fine and very fine pores; slightly alkaline (pH 7.4); abrupt smooth boundary. (18 to 32 inches thick)
A2--33 to 60 inches; very dark brown (10YR 2/2) silt loam, dark grayish brown (10YR 4/2) dry; massive; slightly hard, friable, slightly stick and slightly plastic; common fine and very fine roots; slightly alkaline (pH 7.4).
TYPE LOCATION: Spokane County, Washington; 200 feet south and 50 feet west of the northeast corner, sec. 20, T. 26 N., R. 40 E. W.M.
RANGE IN CHARACTERISTICS: The thickness of the mollic epipedon and depth to contrasting material is more than 40 inches and commonly exceeds 5 feet. The mean annual soil temperature is 47 to 54 degrees F. These soils are usually moist, but are dry in all parts between 4 and 12 inches for 60 to 75 consecutive days. The control section is silt loam with 10 to 18 percent clay and 70 to 80 percent silt.
The Ap horizon has chroma of 1 or 2 moist or dry. It has weak or moderate granular structure. It is slightly alkaline or to slightly acid.
The A horizon, to a depth of at least 40 inches, has value of 2 to 4 dry, 2 or 3 moist, and chroma of 1 or 2 moist or dry. Below 40 inches the value is 3 to 5 and chroma is 1 to 3. It is slightly alkaline or neutral.
COMPETING SERIES: These are the Covello, Hermiston, Onyx, Pedigo, Powder and Touchet series. Covello soils are calcareous in the lower part of the control section and are moderately alkaline or strongly alkaline throughout. Hermiston soils are calcareous in the lower part of the control section and have a mollic epipedon less than 3 feet thick. Onyx soils are dry for more than 90 consecutive days and have value of 3 moist, 5 dry in most of the control section. Pedigo soils are calcareous throughout. Powder soils have an aridic moisture regime and are dry for 90 to 120 consecutive days. Touchet soils are dry for 75 to 90 consecutive days and have redox concentrations at 30 inches or more and are moderately well drained.
GEOGRAPHIC SETTING: Mondovi soils are on flood plains and drainageways at elevations of 1,500 to 3,100 feet. The soils formed in silty alluvium from loess washed from the uplands and deposited in narrow tributary stream bottoms. Summers are hot and dry and winters are cold and moist. Average annual precipitation is 15 to 20 inches. Average January temperature is about 28 degrees F, average July temperature is about 68 degrees F, and mean annual temperature is about 48 degrees F. The average frost-free season is about 110 to 160 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Athena, Caldwell, and Palouse soils, and the competing Covello soils. Athena and Palouse soils have a regular decrease of organic matter with depth. Caldwell soils are more than 18 percent clay.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; moderate permeability. Flooding is rare or occasional.
USE AND VEGETATION: These soils are used for cropland. Common crops are small grains, alfalfa, and grass. Native vegetation was bluebunch wheatgrass, giant wildrye, Idaho fescue, willow, and wild rose.
DISTRIBUTION AND EXTENT: Palouse area of eastern Washington, northeastern Oregon, and northern Idaho. The soils are of moderate extent.
MLRA OFFICE RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Spokane County, Washington, 1964.
REMARKS: Diagnostic horizons and features recognized in this pedon is a mollic epipedon with an irregular decrease in organic carbon from the surface to more than 60 inches.