LOCATION MATHENY WA+OR

Established Series
Rev. HRG/RJE/RWL
12/2022

MATHENY SERIES

The Matheny series consists of deep, well drained soils formed in colluvium and slope alluvium from weathered basalt and loess with some volcanic ash on canyon walls, slump blocks, and footslopes. Slopes are 10 to 90 percent. The average annual precipitation ranges from 14 to 18 inches and the average annual air temperature is about 47 degrees F.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Calcic Pachic Argixerolls

TYPICAL PEDON: Matheny silt loam, range on a 64 percent north-facing slope at an elevation of 2,180 feet. (Colors are for dry soils unless otherwise noted)

A1--0 to 4 inches; very dark grayish brown (10YR 3/2) silt loam, black (10YR 2/1) moist; weak fine and medium granular structure; soft; very friable, slightly sticky and slightly plastic; many very fine roots; many very fine irregular pores; 5 percent gravel; neutral (pH 6.8); clear wavy boundary. (3 to 6 inches)

A2--4 to 8 inches; very dark grayish brown (10YR 3/2) silt loam, black (10YR 2/1) moist; weak fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and few medium roots; many very fine irregular pores; 5 percent gravel; neutral (pH 6.8); clear wavy boundary. (3 to 14 inches thick)

AB--8 to 14 inches; dark grayish brown (10YR 4/2) silt loam, very dark brown (10YR 2/2) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and few medium roots; common very fine irregular pores; 5 percent gravel; neutral (pH 7.0); clear wavy boundary. (4 to 11 inches thick)

2Bt--14 to 22 inches; dark grayish brown (10YR 4/2) very cobbly clay loam, very dark brown (10YR 2/2) moist; moderate medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; many very fine roots; common very fine irregular pores; many faint stress cutans and clay films on faces of peds and clay films lining some pores; 25 percent graveland 20 percent cobbles; neutral (pH 7.2); clear wavy boundary. (5 to 17 inches thick)

2Bk1--22 to 33 inches; brown (10YR 5/3) extremely cobbly loam, dark brown (10YR 3/3) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine roots; common very fine irregular pores; common coatings of secondary lime on undersides of basalt fragments and few irregular coarse masses of lime; 30 percent gravel, 30 percent cobbles and 5 percent stones; slightly effervescent; moderately alkaline (pH 8.4): clear wavy boundary. (0 to 13 inches thick)

2Bk2--33 to 44 inches; brown (10YR 5/3) extremely cobbly loam, dark brown (10YR 3/3) moist; massive; hard, friable, moderately sticky and moderately plastic; few very fine roots; common very fine irregular pores; many coatings of lime on underside of basalt fragments and common irregular coarse masses of secondary lime; 30 percent gravel, 40 percent cobbles and 5 percent stones; strongly effervescent; strongly alkaline (pH 8.6); abrupt irregular boundary. (5 to 20 inches thick)

3R--44 inches; basalt.

TYPE LOCATION: Asotin County, Washington; about 5 miles northeast of Anatone; 600 feet east and 2,100 feet north of southwest corner sec. 34, T. 9 N., R. 46 E.

RANGE IN CHARACTERISTICS: The depths to secondary lime is 20 to 40 inches. Depth to basalt is 40 to more than 60 inches. The mean annual soil temperature is about 48 degrees F. The soils are usually moist, but are dry in all parts between the depth of 4 and 12 inches for 75 to 90 consecutive days during summer and fall. The particle-size control section averages 25 to 35 percent clay and 35 to 60 percent angular basalt fragments by volume. The mollic epipedon is 20 to 35 inches thick and includes all or part of the argillic horizon.

The A2 horizon has value of 3 or 4 dry, and chroma of 1 or 2 dry or moist. It is silt loam, gravelly silt loam or cobbly silt loam.

The AB horizon has value of 4 or 5 dry, 2 or 3 moist, and chroma of 2 or 3 dry or moist. It is silt loam, gravelly silt loam, cobbly silt loam, cobbly loam or very cobbly loam.

The 2Bt horizon has value of 4 or 5 dry, 2 or 3 moist, and chroma of 2 or 3 dry or moist. It is very gravelly clay loam, very cobbly clay loam, very gravelly loam or very cobbly loam. It is neutral or slightly alkaline. Some pedons have a Btk horizon.

The 2Bk horizon has value of 5 through 7 dry, 3 through 5 moist and chroma of 2 or 3 dry or moist. It is extremely cobbly loam, very cobbly loam, extremely gravelly loam, very cobbly loam, very gravelly clay loam or very cobbly clay loam. The Bk horizon is moderately alkaline or strongly alkaline.

COMPETING SERIES: These are the Yergenson and Vosset (I) series. Yergenson soils lack a Bk horizon and lack a loess mantle. Vosset soils lack a loess mantle and are coarse sandy loam or loamy sand in the fine earth fraction in the lower part of the particle-size control section.

GEOGRAPHIC SETTING: Matheny soils are on canyon walls and slump blocks. Slopes are 10 to 90 percent. They formed in colluvium and slope alluvium from basalt and loess with some volcanic ash. Elevation ranges from 900 to 3,300 feet. Summers are warm and dry and winters are cool and moist. The average annual precipitation ranges from 14 to 18 inches. The average annual air temperature is 45 to 51 degrees F. Frost-free season is 120 to 145 days.

GEOGRAPHICALLY ASSOCIATED SOILS: They are the Laufer, Limekiln, Pataha, Rockly, Stember and Thiessen soils. Laufer, Limekiln, Pataha, Rockly, Stember and Thiessen soils have a lithic contact at a depth of less than 40 inches.

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

USE AND VEGETATION: Used for livestock grazing. Native vegetation is mainly bluebunch wheatgrass, Idaho fescue and rose.

DISTRIBUTION AND EXTENT: Southeast Washington and northeastern Oregon; MLRA 9. The series is of small extent.

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

SERIES ESTABLISHED: Asotin County, Washington, 1984.

REMARKS: Diagnostic horizon and features recognized in this pedon are:

mollic epipedon- from the surface to 22 inches
argillic horizon - from 14 to 22 inches
lime accumulation - from 33 to 44 inches

National Cooperative Soil Survey
U.S.A.