LOCATION OWHI                    WA

Established Series
Rev. CDL/SBC/RJE
01/2011

OWHI SERIES


The Owhi series consists of very deep, well drained soils formed in glacial outwash with a component of loess and volcanic ash in the upper part. These soils are on outwash terraces and terrace escarpments. Slopes are 0 to 45 percent. The mean annual precipitation is about 13 inches, and the mean annual air temperature is about 48 degrees F.

TAXONOMIC CLASS: Sandy-skeletal, mixed, mesic Vitrandic Haploxerolls

TYPICAL PEDON: Owhi ashy fine sandy loam - on a 2 percent northwest-facing slope under native range vegetation at an elevation of 1,540 feet. (Colors are for moist soil unless otherwise noted.)

A1--0 to 5 inches; dark grayish brown (10YR 4/2) ashy fine sandy loam, very dark brown (10YR 2/2) moist; moderate fine granular structure; soft, very friable, nonsticky, nonplastic; many very fine and fine roots; 5 percent gravel; slightly acid (pH 6.4); gradual smooth boundary.

A2--5 to 11 inches; yellowish brown (10YR 5/6) ashy fine sandy loam, very dark grayish brown (10YR 3/2) moist; moderate fine subangular blocky structure; soft, very friable, nonsticky, nonplastic; many very fine and fine roots; 5 percent gravel; neutral (pH 6.6); clear smooth boundary. (Combined thickness of the A horizon is 7 to 15 inches)

2Bw--11 to 24 inches; brown (10YR 5/3) gravelly sandy loam, dark brown (10YR 3/3) moist; weak fine subangular blocky structure; soft, very friable, nonsticky, nonplastic; common very fine and fine roots; 15 percent gravel, 5 percent cobbles; neutral (pH 6.6); clear smooth boundary. (5 to 15 inches thick)

2CB--24 to 31 inches; brown (10YR 5/3) very gravelly loamy sand, dark brown (10YR 3/3) moist; massive; soft, very friable, nonsticky, nonplastic; common very fine and fine roots; 30 percent gravel, 10 percent cobbles, 5 percent stones; neutral (pH 6.6); clear smooth boundary. (0 to 12 inches thick)

2C--31 to 60 inches; multicolored extremely gravelly coarse sand; single grained; loose; few very fine and fine roots; 60 percent gravel, 10 percent cobbles; neutral (pH 6.8).

TYPE LOCATION: Okanogan County, Washington; about 5 miles west of the town of Riverside; 1,450 feet south, 2,700 feet west in northeast corner sec. 30, T.35N., R.26E., WM (Latitude 48 degrees, 31 minutes, 31 seconds North, Longitude 119 degrees, 36 minutes, 51 seconds West NAD 83).

RANGE IN CHARACTERISTICS: The mean annual temperature is 47 to 52 degrees F. These soils are usually moist but are dry in all parts between a depth of 12 and 35 inches for 90 to 105 consecutive days following the summer solstice. The mollic epipedon is 7 to 15 inches thick. Solum thickness is 12 to 26 inches with some part having base saturation of less than 75 percent. The particle-size control section averages 35 to 50 percent rock fragments.

The A horizon has value of 4 or 5 dry and 2 or 3 moist, and chroma of 2 or 3 dry or moist. It is 0 to 25 percent gravel, 0 to 25 percent cobbles and stones. Reaction is slightly acid or neutral. It has 10 to 30 percent glass and acid oxalate extractable aluminum plus one-half the iron is 0.15 to 0.40 percent.

The Bw horizon has value of 5 or 6 dry , 3 or 4 moist, and chroma of 2 through 4 dry or moist. It is sandy loam, fine sandy loam or loam and is gravelly in some pedons. It is 10 to 30 percent gravel, 0 to 10 percent cobbles. Reaction is slightly acid or neutral.

The CB horizon has value of 5 or 6 dry, 3 or 4 moist, and chroma of 3 or 4 dry or moist. It is sandy loam, coarse sandy loam or loamy sand with 5 to 12 percent clay and is very gravelly. It is 35 to 60 percent gravel, 0 to 15 percent cobbles. This horizon is absent in some pedons.

The C horizon is commonly multicolored, but can have hue of 10YR or 2.5Y, value of 5 through 7 dry, 4 through 6 moist, and chroma of 2 through 4 dry or moist. It is loamy sand, sand or coarse sand with 0 to 5 percent clay and is very gravelly or extremely gravelly. Reaction is neutral or slightly alkaline.

COMPETING SERIES: These are the Alecanyon, Leiko and Sequim series. Alecanyon soils have silica accumulations in the subsoil. Leiko and Sequim soils are dry 75 to 90 days.

GEOGRAPHIC SETTING: Owhi soils are on outwash terraces and terrace escarpments. Slopes are 0 to 45 percent. Elevations range from 1,000 to 4,000 feet. These soils formed in glacial outwash with a component of loess and volcanic ash. The climate is characterized by warm, dry summers and cool, moist winters. The mean annual precipitation is 10 to 15 inches. The mean January temperature is about 25 degrees F, the mean July temperature is about 71 degrees F, and the mean annual air temperature is about 48 degrees F. The frost-free season is 110 to 150 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Conconully, Ewall, Fivelakes, Haley, Hobohill, and Nespelem soils. Conconully soils are coarse-loamy. Ewall soils are sandy throughout the profile. Fivelakes soils are loamy-skeletal. Haley soils are coarse-loamy over sandy or sandy-skeletal. Hobohill soils are sandy in the particle-size control section. Nespelem soils are coarse-silty and calcareous in the lower part of the control section.

DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; moderate to moderately rapid permeability.

USE AND VEGETATION: Irrigated orchards, hay, and pasture, small grains, and range. Native vegetation includes bluebunch wheatgrass, needleandthread, Wyeth eriogonum, common gallardia, silky lupine, hood phlox, and threetip sagebrush.

DISTRIBUTION AND EXTENT: North central Washington. The series is moderately extensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon

SERIES ESTABLISHED: Okanogan County, Washington, 1972.

REMARKS: Diagnostic horizons and features recognized in this soil are a mollic epipedon from the surface to 11 inches, a cambic horizon from 11 to 24 inches, and 41 percent rock fragments by weighted average in the 10- to 40-inch particle-size control section.


National Cooperative Soil Survey
U.S.A.