LOCATION WALLA WALLA WA+OREstablished Series
TAXONOMIC CLASS: Coarse-silty, mixed, superactive, mesic Typic Haploxerolls
TYPICAL PEDON: Walla Walla silt loam - cultivated. (Colors for dry soils unless otherwise noted)
Ap--0 to 6 inches; dark grayish brown (10YR 4/2) silt loam, very dark brown (10YR 2/2) moist; weak fine granular structure; slightly hard, friable, slightly sticky, slightly plastic; many roots; many very fine tubular pores; neutral (pH 6.8); abrupt smooth boundary. (5 to 7 inches thick)
A--6 to 13 inches; grayish brown (10YR 5/2) silt loam, very dark grayish brown (10YR 3/2) moist; weak medium platy structure; slightly hard, friable, slightly sticky, slightly plastic; many roots; many very fine tubular pores; neutral (pH 6.8); clear smooth boundary. (5 to 7 inches thick)
AB--13 to 18 inches; brown (10YR 5/3) silt loam, dark brown (10YR 3/3) moist; weak coarse prismatic parting to weak subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic; common roots; many very fine tubular pores; slightly alkaline (pH 7.4); clear wavy boundary. (0 to 10 inches thick)
Bw--18 to 45 inches; brown (10YR 5/3) silt loam, brown (10YR 4/3) moist; weak coarse prismatic structure; slightly hard, friable, slightly sticky, slightly plastic; common roots; common very fine tubular pores; slightly alkaline (pH 7.6); gradual wavy boundary. (16 to 39 inches thick)
Bk1--45 to 55 inches; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; weak coarse prismatic structure; slightly hard, friable, slightly sticky, slightly plastic; few roots; few very fine tubular pores; weakly calcareous with lime in old root channels; moderately alkaline (pH 8.3); gradual wavy boundary. (0 to 15 inches thick)
Bk2--55 to 65 inches; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; massive; slightly hard, friable, slightly sticky, slightly plastic; few roots; few very fine tubular pores; strongly calcareous with disseminated lime; strongly alkaline (pH 8.8).
TYPE LOCATION: Adams County, Washington; 1,600 feet north and 100 feet west of the southeast corner of section 31, T. 20 N., R. 37 E.
RANGE IN CHARACTERISTICS: These soils are usually moist, but are dry in all parts from 4 to 12 inches for 90 to 105 consecutive days following summer solstice. Depth to basalt ranges from 40 to more than 60 inches. In some pedons, a cemented substratum occurs at a depth of 40 to 60 inches. Depth to secondary carbonates ranges from 44 to more than 60 inches. The mollic epipedon ranges from 10 to 20 inches in thickness. The mean annual soil temperature is 49 to 56 degrees F. The particle-size control section has 10 to 18 percent clay.
The A horizon has value of 4 or 5 dry, 2 or 3 moist and chroma of 2 or 3 dry and moist. Reaction is neutral or slightly alkaline.
The AB horizon, when present, has value of 4 or 5 dry, 2 or 3 moist and chroma of 2 or 3. Reaction is neutral or slightly alkaline. Some pedons have a BA horizon.
The Bw horizon has value of 5 or 6 dry, 3 or 4 moist and chroma of 3 or 4 moist or dry. It has weak subangular blocky or prismatic structure. Reaction is neutral or slightly alkaline.
The Bk horizon has value of 5 to 7 dry, 3 to 5 moist and chroma of 2 to 4 dry and moist. It is massive or has weak prismatic structure. Reaction is slightly alkaline to strongly alkaline.
Some pedons have an indurated hardpan at a depth of 40 to 60 inches.
COMPETING SERIES: This is the
Anderly series.
Anderly soils 20 to 40 inches to a lithic contact (basalt); dry for 60 to 90 consecutive days following the summer solstice
GEOGRAPHIC SETTING: Walla Walla soils are on hills at elevations of 150 to 2,600 feet. They formed in loess. These soils occur in a semiarid climate with warm, dry summers and cool, moist winters. The mean annual precipitation of 12 to 15 inches. The average January temperature is about 30 degrees F. and the average July temperature is about 72 degrees F. The mean annual temperature is 48 to 54 degrees F. The frost-free season is 110 to 170 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Alpowa, Anders, Anderly, Benge, Chard, Kuhl, Oliphant, Onyx, Nansene, Spofford, and Walvan soils. Alpowa soils are loamy-skeletal and are on alluvial fans, hills, and plateaus. Anderly, Anders, and Kuhl soils have bedrock at a depth of less than 40 inches. Anderly and Anders soils are on plateaus, benches and channeled scablands. Kuhl soils are on canyon slopes. Benge soils are coarse-loamy over sandy or sandy-skeletal and are on terraces. Chard soils are coarse-loamy and are on terraces. Oliphant soils have a zone of calcium carbonate accumulation beginning at a depth of 15 to 44 inches and are on hillslopes and plateaus. Onyx soils are on associated flood plains and have mollic epipedons more than 20 inches thick. Nansene soils are on steep north slopes and have mollic epipedons thicker than 20 inches. Spofford soils have natric horizons and are on plateaus and hills. Walvan soils are dominantly volcanic ash and are on uplands.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; moderate permeability.
USE AND VEGETATION: These soils are used for dryland cropland, irrigated cropland and some is used for livestock grazing. Native vegetation is bluebunch wheatgrass, Sandberg bluegrass, big bluegrass, arrowleaf balsamroot, western yarrow, and sagebrush.
DISTRIBUTION AND EXTENT: Southeastern Washington and northeastern Oregon. MLRA 8. Series is extensive.
MLRA OFFICE RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Walla Walla County, Washington, 1902.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the zone from 0 to 18 inches
Cambic horizon - the zone from 18 to 45 inches
Carbonate accumulation - the zone from 45 to 60 inches
Particle-size control section - the zone from 10 to 40 inches