LOCATION NANSENE OR+WAEstablished Series
TAXONOMIC CLASS: Coarse-silty, mixed, superactive, mesic Pachic Haploxerolls
TYPICAL PEDON: Nansene silt loam, rangeland. (Colors are for moist soil unless otherwise noted.)
A1--0 to 3 inches; very dark brown (10YR 2/2) coarse silt loam, dark grayish brown (10YR 4/2) dry; weak thin platy and weak very fine granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine roots; many very fine irregular pores; slightly acid (pH 6.5); abrupt wavy boundary. (3 to 6 inches)
A2--3 to 10 inches; very dark brown (10YR 2/2) coarse silt loam, dark grayish brown (10YR 4/2) dry; very weak thick platy and very weak medium granular structure; soft, very friable, slightly sticky and slightly plastic; common very fine roots; many very fine irregular pores; neutral (pH 6.6); clear smooth boundary. (5 to 8 inches thick)
A3--10 to 20 inches; very dark brown (10YR 2/2) coarse silt loam, dark grayish brown (10YR 4/2) dry; weak coarse prismatic structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine roots; many very fine tubular pores; neutral (pH 6.6); clear smooth boundary. (6 to 12 inches thick)
Bw--20 to 37 inches; very dark brown (10YR 2/2) coarse silt loam, brown (10YR 4/3) dry; weak coarse prismatic structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine roots; many very fine tubular pores; neutral (pH 6.6); clear smooth boundary. (13 to 32 inches thick)
C--37 to 54 inches; dark brown (10YR 3/3) coarse silt loam, brown (10YR 4/3) dry; massive; slightly hard, very friable, slightly sticky and slightly plastic; common very fine roots; common very fine tubular pores; neutral (pH 6.6); abrupt smooth boundary. (0 to 18 inches thick)
2R--54 inches; basalt.
TYPE LOCATION: Sherman County, Oregon; SE1/4 SW1/4 section 12, T.1N., R.15E.
RANGE IN CHARACTERISTICS: In most years the soils are usually moist but are dry throughout the control section for 70 to 90 consecutive days within the 4 months following the summer solstice. The mean annual soil temperature is 49 to 54 degrees F. Depth to basalt is 40 to more than 60 inches. The profile is silt loam throughout to depth of 40 inches and has 10 to 18 percent clay and less than 15 percent coarser than very fine sand. There are 0 to 5 percent fragments of basalt 1 inch or less in diameter in the control section and up to 5 percent larger fragments mostly on the surface. Up to 10 percent of the surface has exposed bedrock in some areas. The mollic epipedon ranges from 30 to 50 inches thick. The solum has hue of 10YR or 7.5YR.
The A horizon has value of 2 or 3 moist, 4 or 5 dry and chroma of 1 or 2 moist and 1 thru 3 dry. It has weak thin platy, weak fine granular to weak coarse prismatic structure. It is slightly acid to slightly alkaline.
The Bw horizon has value of 4 or 5 dry, 2 or 3 moist and chroma of 2 or 3 moist and dry. It has weak, coarse, or medium prismatic structure. It is slightly acid to slightly alkaline.
The C horizon, when present, has value of 4 through 7 dry and 3 through 5 moist and chroma of 2 through 4 moist and dry. Below depth of 43 inches it is weakly calcareous in some pedons. Some pedons have a BC horizon with colors like the C horizon or a Bk horizon below a depth of 40 inches. It is neutral to moderately alkaline.
COMPETING SERIES: This is the
Powval series.
Powval soils dry for greater than 90 consecutive days following the summer solstice; calcium carbonate accumulations above 40 inches.
GEOGRAPHIC SETTING: The Nansene soils have north-facing slopes and are on canyon side slopes, hillslopes, and plateaus. Slopes are 2 to 70 percent. Elevation is 200 to 2,700 feet. The soils formed in loess. The climate is characterized by cool wet winters and hot dry summers. The mean winter temperature is 33 to 37 degrees F.; the mean summer temperature is 63 to 67 degrees F. The mean annual temperature is 48 to 52 degrees F. The mean annual precipitation is 11 to 15 inches. The frost-free period is 135 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Anderly, Dufur, Lickskillet, Rhea, Ritzville, Walla Walla, Wato and Wrentham soils. Anderly soils are 20 to 40 inches deep to bedrock and are on plateaus and side slopes. Dufur soils are coarse-loamy and are on south-facing slopes. Lickskillet soils are skeletal, less than 20 inches deep and are on steep to very steep south-facing slopes on canyons. Rhea soils are fine-silty and calcareous and are on plateaus and side slopes. Ritzville soils are on south-facing slopes of plateaus, canyons, and hills, usually dry, and have a mollic epipedon less than 20 inches thick. Wato soils are coarse-loamy, have a mollic epipedon less than 20 inches thick and are on upland terraces. Walla Walla soils have a mollic epipedon 10 to 20 inches thick and are on hillslopes. Wrentham soils are skeletal and are 20 to 40 inches deep to bedrock and are on canyon slopes.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: These soils are used primarily for livestock grazing. Other uses are wildlife and water supply purposes. Vegetation is mainly Idaho fescue, Sandberg bluegrass, bluebunch wheatgrass, forbs and shrubs.
DISTRIBUTION AND EXTENT: North-central Oregon and southeastern Washington; MLRA 8. This series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Sherman County, Oregon, 1959.
REMARKS: Diagnostic horizons and features in this pedon include:
Mollic epipedon - from surface to 37 inches (A1, A2, A3, and Bw horizons).
Particle-size control section - from 10 to 40 inches (A3, Bw, and upper 3 inches of C horizon)