LOCATION EVANS OREstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Cumulic Haploxerolls
TYPICAL PEDON: Evans loam, near a cultivated field, along fence row. (Colors are for moist soil unless otherwise noted.)
A1--0 to 8 inches; very dark brown (10YR 2/2) loam, dark grayish brown (10YR 4/2) dry; moderate very fine and fine subangular blocky structure parting to moderate very fine granular; soft, friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine and fine irregular and tubular pores; 10 percent gravel; moderately acid (pH 6.0); abrupt smooth boundary. (6 to 10 inches thick)
A2--8 to 26 inches; very dark brown (10YR 2/2) loam, dark grayish brown (10YR 4/2) dry; moderate very fine and fine subangular blocky structure; soft, friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine and fine irregular and tubular pores; 10 percent gravel; slightly acid (pH 6.2); clear smooth boundary. (3 to 20 inches thick)
A3--26 to 38 inches; very dark brown (10YR 2/2) loam, brown (10YR 5/3) dry; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine roots; many very fine and fine irregular and tubular pores; 5 percent gravel; slightly acid (pH 6.3); clear smooth boundary. (0 to 20 inches thick)
C--38 to 60 inches; dark brown (7.5YR 3/2) loam, yellowish brown (10YR 5/4) dry; massive; slightly hard, friable, slightly sticky and slightly plastic; common very fine, fine, and medium roots; many very fine and fine irregular and tubular pores; 2 percent gravel; slightly acid (pH 6.4).
TYPE LOCATION: Jackson County, Oregon; about 2 miles south of Shady Cove approximately 1,400 feet west and 300 feet north of the southeast corner of sec. 29, T. 34 S., R. 1 W., W.M.
RANGE IN CHARACTERISTICS: Solum thickness is typically 20 to 40 inches. Depth to bedrock is 60 inches or more. The mean annual soil temperature is 52 to 56 degrees F. The soils are usually moist but are dry between depths of 8 and 24 inches for 80 to 110 consecutive days following the summer solstice. The mollic epipedon is 20 to 40 inches thick. The soil has an irregular decrease in organic carbon and has over 0.3 percent organic carbon to a depth of 50 inches. The 10- to 40-inch particle-size control section averages 10 to 18 percent clay and has texture of loam, silt loam, or very fine sandy loam.
The A horizon has hue of 10YR or 7.5YR, value of 2 or 3 moist, 4 or 5 dry and chroma of 2 or 3 moist and 2 through 4 dry. It has 12 to 18 percent clay and 0 to 5 percent gravel.
The C horizon has hue of 10YR or 7.5YR, value of 3 or 4 moist, 4 through 6 dry, and chroma of 2 or 3 moist and 2 through 4 dry. It is silt loam, loam, or very fine sandy loam with 10 to 18 percent clay and 0 to 5 percent gravel.
COMPETING SERIES: These are the Coxlake, Endersby, Leavenworth, Narcisse, Okanogan, Patit Creek, Pleasant Veiw, Poween and Redola series. Coxlake soils are somewhat poorly drained with mottles of chroma 2 or less above 30 inches. Endersby soils are mildly alkaline or moderately alkaline in the C horizon. Leavenworth soils are neutral or mildly alkaline in the C horizon and have strata of loamy fine sand in the control section. Narcisse soils are mottled at 20 to 40 inches and are dry for 60 to 80 consecutive days. Okanogan soils are neutral to moderately alkaline throughout or in some part of the particle-size control section. Patit Creek soils are very gravelly in the lower part of the control section. Pleasant View and Redola soils are calcareous throughout or in some part of the particle-size control section. Poween soils are moderately or strongly alkaline throughout.
GEOGRAPHIC SETTING: Evans soils are on flood plains at elevations of 100 to 3,000 feet. Slopes range from 0 to 3 percent. The soils formed in mixed alluvium. The climate is characterized by hot, dry summers and warm, moist winters. The mean July temperature is 72 degrees F; the mean January temperature is 37 degrees F; the mean annual temperature is 50 to 56 degrees F. The frost-free period is 140 to 235 days. The mean annual precipitation is typically 18 to 60 inches. In the interior river valleys of Curry County, Oregon, the mean annual precipitation ranges to 90 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Camas, Central Point, and Newberg soils. Camas and Newberg soils have a mollic epipedon less than 20 inches thick and occur on flood plains. Camas soils are sandy-skeletal. Central Point soils have a regular decrease in organic carbon content with increasing depth, and occur on low stream terraces and alluvial fans.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability. Occasional flooding occurs for brief periods from December to March.
USE AND VEGETATION: Evans soils are used for fruit production, small grains, corn, hay and pasture. Native vegetation is an open stand of Douglas fir, ponderosa pine and oak with an understory of brush and grass.
DISTRIBUTION AND EXTENT: Interior valleys of Southwestern Oregon, MLRA 5. The series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Medford Area, Oregon, 1911.
REMARKS: CEC activity class superactive added 1/2000, competing series not updated at that time.
Diagnostic horizons and features:
- Mollic epipedon - 0 to 38 inches.
- Assume organic carbon is greater than 0.3 percent at 50 inches.