LOCATION UKIAH OREstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Vertic Argixerolls
TYPICAL PEDON: Ukiah silty clay loam, rangeland. (Colors are for moist soil unless otherwise noted.)
A--0 to 2 inches; very dark brown (10YR 2/2) silty clay loam, dark grayish brown (10YR 4/2) dry; moderate fine and medium granular structure; hard, firm, slightly sticky and slightly plastic; many very fine and fine roots; many very fine and fine pores; neutral (pH 6.6); abrupt smooth boundary.
BA--2 to 10 inches; very dark grayish brown (10YR 3/2) silty clay, brown (10YR 4/3) dry; moderate medium and fine subangular blocky structure; hard, firm, sticky and plastic; common very fine and fine roots; neutral (pH 6.6); clear smooth boundary.
Bt1--10 to 18 inches; dark brown (7.5YR 3/2) clay, brown (7.5YR 4/2) dry; strong coarse and medium angular blocky structure; very hard, very firm, very sticky and very plastic; few very fine and fine roots; common distinct clay films on faces of peds; neutral (pH 6.6); clear smooth boundary.
Bt2--18 to 28 inches; dark brown (7.5YR 3/3) clay, brown (7.5YR 4/2) dry; strong coarse and medium angular blocky structure; very hard, very firm, very sticky and very plastic; few very fine roots; many distinct clay films on faces of peds; neutral (pH 6.8); abrupt smooth boundary.
C--28 to 36 inches; brown (7.5YR 4/4) loam, reddish yellow (7.5YR 6/6) dry; massive; hard, firm, nonsticky and nonplastic; neutral (pH 7.2); gradual smooth boundary. (0 to 8 inches thick)
2Cr--36inches; highly weathered volcanic tuff.
TYPE LOCATION: Baker County, Oregon; about 2.5 miles south of Halfway, 1,600 feet south and 800 feet east of the southwest corner of Section 28, T.8S., R.46E.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 47 to 51 degrees F. The soils are dry during the four months following the summer solstice for 60 to 90 consecutive days in all parts between depths of 4 and 12 inches. The mollic epipedon is 15 to 30 inches thick. Depth to the paralithic contact is 20 to 40 inches. The soil has cracks in the summer in most years that are at least 1 cm wide at a depth of 20 inches and that extend to the surface, or to the base of the Ap horizon if cultivated. Percentage of surface covered with stones ranges from about 0.1 to 15 percent. The solum is slightly acid to neutral.
The A horizon has value of 3 or 4 dry, 2 or 3 moist and chroma of 1 or 2 moist and dry.
The Bt horizon has hue of 10YR or 7.5YR, value of 4 or 5 dry and 2 or 3 moist in the upper part and 5 or 6 dry and 3 or 4 moist in the lower part. Chroma is 2 or 3. The Bt horizon has weak or moderate prismatic and strong or moderate blocky or subangular blocky structure. It has 40 to 60 percent clay and 0 to 35 percent rock fragments. It is silty clay, clay, cobbly clay or cobbly silty clay.
The C horizon, when present, has hue of 7.5YR or 10YR, value of 4 or 5 dry, 3 to 5 moist and chroma of 4 or 6 moist and dry. It is loam or silty clay loam with 0 to 20 percent gravel and cobbles. It is neutral to moderately alkaline.
COMPETING SERIES: These are the Ayette, Darow, Forsgren, Gimmi, Hann, Karney, Kuck, McDesh, Montour and Tub series. Ayette, Forsgren, Hann, Karney, Montour and Tub soils are over 40 inches deep to a root restrictive layer. Darow soils have a soil temperature of 54 to 56 degrees F. Fimmi soils have a 8 to 15 inch thick molic epipedon. Kuck soils have a soil temperature of 51 to 57 degrees F. McDesh soils have a lithic contact at 20 to 40 inches.
GEOGRAPHIC SETTING: Ukiah soils are on hills. Slope is 2 to 40 percent. Elevation is 2,400 to 4,600 feet. Near the upper elevation range, the soils are mainly on south slopes. The soils formed in colluvium from basalt and volcanic tuff. The surface is influenced by loess in some places. Mean annual precipitation ranges from 14 to 21 inches. Mean annual air temperature is 45 to 50 degrees F. Mean July temperature is about 67 degrees F, and mean January temperature is about 30 degrees F. The frost-free period is 80 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Gwin, Gwinly, Rockly, Starkey, Tub and Waterbury soils. Gwin, Gwinly, Rockly and Waterbury soils are less than 20 inches deep to basalt. Tub soils lack a paralithic contact above a depth of 40 inches. Starkey soils are shallow to a paralithic contact.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; very slow permeability.
USE AND VEGETATION: Mainly range. Some areas are cultivated for dryland hay and small grains. Native vegetation is mainly Idaho fescue, bluebunch wheatgrass and Sandberg bluegrass.
DISTRIBUTION AND EXTENT: Hills of east-central and northeastern Oregon. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Grant County, Oregon, 1975.
REMARKS: Diagnostic horizons and other features:
Mollic epipedon - from 0 to 28 inches
Argillic horizon - from 2 to 28 inches
In 2003 the series type location was moved to Baker County, Oregon. The previous type location in Grant County, Oregon was correlated to the Prill series.