LOCATION MEDFORD OR+CAEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Pachic Argixerolls
TYPICAL PEDON: Medford silty clay loam - cultivated. (Colors are for moist soil unless otherwise noted.)
Ap--0 to 8 inches; very dark brown (10YR 2/2) silty clay loam, very dark grayish brown (10YR 3/2) dry; moderate fine subangular blocky and granular structure; very hard, firm, sticky and plastic; many very fine roots; many very fine irregular pores; neutral (pH 6.6); abrupt smooth boundary. (5 to 10 inches thick)
A--8 to 12 inches; very dark brown (10YR 2/2) silty clay loam, dark grayish brown (10YR 4/2) dry; moderate medium subangular blocky structure; very hard, firm, sticky and plastic; many very fine roots; many very fine tubular pores; slightly acid (pH 6.4); clear smooth boundary. (3 to 6 inches thick)
Bt1--12 to 22 inches; very dark brown (10YR 2/2) silty clay, dark grayish brown (10YR 4/2) dry; moderate fine prismatic structure parting to moderate fine subangular blocky; very hard, firm, very sticky and very plastic; few medium roots; many very fine tubular pores; many moderately thick clay films; slightly acid (pH 6.4); clear smooth boundary. (8 to 12 inches thick)
Bt2--22 to 35 inches; dark brown (10YR 3/3) silty clay loam, dark grayish brown (10YR 4/2) dry; weak fine prismatic structure parting to moderate fine subangular blocky; very hard, firm, sticky and very plastic; few medium roots; many very fine tubular pores; common moderately thick very dark brown (10YR 2/2) clay films; moderately acid (pH 6.4); gradual wavy boundary. (9 to 15 inches thick)
Bt3--35 to 44 inches; dark yellowish brown (10YR 3/4) silty clay loam, dark grayish brown (10YR 4/2) dry; moderate medium subangular blocky structure; very hard, firm, sticky and very plastic; few medium roots; many very fine tubular pores; common moderately thick dark brown (10YR 3/3) clay films; slightly acid (pH 6.4); gradual wavy boundary. (8 to 12 inches thick)
Bt4--44 to 53 inches; dark yellowish brown (10YR 3/4) heavy clay loam, dark brown (10YR 4/3) dry; weak medium subangular blocky structure; very hard, firm, sticky and very plastic; few medium roots; many very fine tubular pores; common moderately thick dark brown (10YR 3/3) clay films; slightly acid (pH 6.4); gradual wavy boundary. (0 to 12 inches thick)
2BCt--53 to 71 inches; dark yellowish brown (10YR 3/4) sandy clay loam, dark brown (10YR 4/3) dry; massive, hard, firm, sticky and plastic; common fine tubular pores; few moderately thick dark brown (10YR 3/3) clay films; slightly acid (pH 6.4).
TYPE LOCATION: Jackson County, Oregon; 1 mile north of Central Point, approximately 1,220 feet north and 580 feet east of the southwest corner of sec. 35, T. 36 S., R. 2 W.
RANGE IN CHARACTERISTICS: The soil is usually moist but is dry throughout, between 4 and 12 inches for 80 to 110 consecutive days during the period of four months following the summer solstice. The mean annual soil temperature is 53 to 57 degrees F. Depth to bedrock is more than 60 inches and the solum is 40 to 60 inches thick. The mollic epipedon is 20 to 40 inches thick. Gravel and cobble content on the surface and in the solum is 0 to 15 percent. The soil ranges from neutral to moderately acid.
The A horizon has value of 2 or 3 moist, 3 through 5 dry, and chroma of 1 or 2 dry. Organic carbon decreases regularly with increasing depth.
The Bt horizon has value of 2 through 4 moist, 4 through 6 dry, and chroma of 2 through 4 moist and dry. It is silty clay loam, clay, silty clay or clay loam with 35 to 45 percent clay. Faint mottles are below 40 inches in some pedons.
The 2BC horizon is stratified sandy clay loam, clay loam or silty clay loam. It has 0 to 60 percent rock fragments.
COMPETING SERIES: These are the Denbar, Deter, Jacknife, Mindego, and Nebeker series. Denbar soils have a mean annual soil temperature of 48 to 52 degrees F, are mildly to moderately alkaline and have a duripan at 40 to 60 inches. Deter soils have mean annual soil temperature of 48 to 53 degrees F. Jacknife soils have mean annual soil temperature of 47 to 52 degrees F. Mindego soils have 9 to 15 degrees F difference between the mean summer and winter soil temperatures and commonly are cobbly or stony in the lower part of the solum. Nebeker soils have 7.5YR and 5YR hue in the Bt horizons and have a calcareous C horizon.
GEOGRAPHIC SETTING: The Medford soils are on stream terraces and alluvial fans. Slopes range from 0 to 15 percent. The soils formed in moderately fine and fine textured alluvium from basic igneous and sedimentary rocks. The soils are at elevations of 1,500 to 4,000 feet. The soils formed under cool, moist winters and warm, dry summers with a mean annual temperature of 50 to 55 degrees F, mean January temperature of 35 to 38 degrees F, and mean July temperature of 69 to 72 degrees F. The mean annual precipitation is 15 to 45 inches. The frost-free period is 125 to 235 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Gregory, Coleman, Cove, Foehlin and Central Point series. Coleman soils have a mollic epipedon less than 20 inches thick. Cove and Gregory soils are poorly drained. Central Point soils are coarse-loamy and lack an argillic horizon. Foehlin soils are fine-loamy and have a mollic epipedon less than 20 inches thick.
DRAINAGE AND PERMEABILITY: Moderately well drained; slow runoff; moderately slow permeability. A water table is at 3 to 6 feet from December to April.
USE AND VEGETATION: These soils are used for urban development, dryfarmed and irrigated locally adapted truck crops, orchards and forage crops.
DISTRIBUTION AND EXTENT: Southwestern Oregon and North Central California. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Jackson County, Medford Area, Oregon, 1911.
REMARKS: The Mindego series description is too old and poorly defined to adequately differentiate.
ADDITIONAL DATA: Charaterization data on one profile (S71-Oreg-15-6) reported on a mimeographed copy from Oregon State University.