LOCATION MCKAY OREstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Calcic Argixerolls
TYPICAL PEDON: McKay silt loam, cultivated. (Colors are for moist soil unless otherwise noted.)
Ap1--0 to 3 inches; very dark brown (10YR 2/2) silt loam, dark grayish brown (10YR 4/2) dry; weak fine platy structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine and fine roots; medium acid (pH 5.9); clear wavy boundary. (3 to 8 inches thick)
Ap2--3 to 11 inches; very dark brown (10YR 2/2) silt loam, dark grayish brown (10YR 4/2) dry; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine and fine roots; medium acid (pH 5.6); clear wavy boundary. (0 to 10 inches thick)
E--11 to 14 inches; very dark grayish brown (10YR 3/2) silt loam, brown (10YR 5/3) dry; moderate medium and coarse prismatic structure; hard, firm, slightly sticky and slightly plastic; few very fine and fine roots; mildly alkaline (pH 7.5); abrupt wavy boundary. (3 to 10 inches thick)
Bt--14 to 20 inches; very dark grayish brown (10YR 3/2) silty clay loam, brown (10YR 5/3) dry; many black (10YR 2/1) organic stains on ped faces; strong medium and coarse columnar structure; very hard, very firm, sticky and plastic; many moderately thick clay films on ped faces and pores; few very fine and fine roots; moderately alkaline (pH 8.0); clear wavy boundary. (5 to 13 inches thick)
Btk--20 to 25 inches; dark yellowish brown (10YR 3/4) silty clay loam, yellowish brown (10YR 5/4) dry; few black (10YR 2/1) organic stains on ped faces; moderate fine and medium prismatic structure; very hard, firm, sticky and plastic; common thin clay films on ped faces; few very fine and fine roots; slightly effervescent, lime disseminated; strongly alkaline (pH 8.6); clear wavy boundary. (4 to 16 inches thick)
2BCk1--25 to 39 inches; brown (7.5YR 4/4) gravelly silt loam, yellowish brown (10YR 5/4) dry; weak medium prismatic structure parting to weak fine and medium subangular blocky; slightly hard, friable, slightly sticky and slightly plastic; few very fine and fine roots; 15 percent gravel; strongly effervescent, lime in seams and filaments; strongly alkaline (pH 8.6); clear wavy boundary. (0 to 17 inches thick)
2BCk2--39 to 47 inches; dark brown (7.5YR 4/3) gravelly silty clay loam, brown (7.5YR 5/3) dry; weak medium prismatic structure parting to weak fine and medium subangular blocky; slightly hard, friable, sticky and slightly plastic; 10 percent gravel and 5 percent cobbles; violently effervescent, lime disseminated; moderately alkaline (pH 8.3); abrupt wavy boundary. (0 to 8 inches thick)
2Ck--47 to 60 inches; pink (7.5YR 8/4) gravelly loam, white (10YR 8/2) dry; massive; slightly hard, friable, slightly sticky and slightly plastic; 20 percent gravel and 5 percent cobbles; violently effervescent, lime disseminated; moderately alkaline (pH 8.3).
TYPE LOCATION: Umatilla County, Oregon; 50 feet north of the road in the SE1/4 SE1/4 SW1/4 of section 32, T. 2 N., R. 33 E.
RANGE IN CHARACTERISTICS: Mean annual soil temperature ranges from 51 to 53 degrees F. These soils are usually moist but 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. Depth to basalt is 60 inches or more. The control section has 27 to 35 percent clay and less than 15 percent coarser than very fine sand. The mollic epipedon is 10 to 18 inches thick.
The Ap horizon has value of 2 or 3 moist, 4 or 5 dry, and chroma of 1 or 2 moist and dry. It has granular, subangular blocky or platy structure. It is medium acid to neutral.
The E horizon has chroma of 2 or 3 moist and dry. It has weak or moderate subangular blocky or prismatic structure. It has 12 to 18 percent clay.
The Bt horizon has value of 4 or 5 dry and chroma of 2 through 4 moist and dry. It has strong medium or coarse columnar structure. It is mildly to strongly alkaline.
The Btk horizon has value of 3 or 4 moist, 5 or 6 dry, and chroma of 3 or 4 moist and dry. It has moderate to strong subangular blocky or prismatic structure. It is strongly to very strongly alkaline. The 2Bck horizon, has hue of 10YR or 7.5YR, value of 5 or 6 dry, and chroma of 3 or 4 moist and dry. It is heavy silt loam, clay loam or silty clay loam with 25 to 35 percent clay, 0 to 5 percent cobbles and 5 to 20 percent gravel.
The 2Ck horizon has hue of 10YR or 7.5YR, value of 5 through 8 moist and dry, and chroma of 2 through 4 moist and dry. It is loam to silty clay loam with 25 to 35 percent clay, 5 to 15 percent cobbles and 15 to 35 percent gravel. It is moderately to strongly alkaline.
COMPETING SERIES: These are the Broadax, Morrow, Nephi and Parleys series. The Broadax and Parleys soils lack coarse fragments below 25 inches and Morrow soils have a lithic contact at 20 to 40 inches. Nephi soils have 5YR hue in the Bt horizon.
GEOGRAPHIC SETTING: McKay soils are on old alluvial fans at elevations of 1450 to 2600 feet. Slopes range from 0 to 25 percent. These soils formed from loess and old alluvium. The climate is subhumid with cool moist winters and warm dry summers. The mean annual precipitation is 14 to 18 inches. The mean annual temperature is 46 to 52 degrees F. The frost-free period is 110 to 160 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Gurdane, Pilot Rock and Waha soils. Pilot Rock soils have a duripan at depths of 20 to 40 inches. Gurdane and Waha soils are on associated uplands and are underlain by basalt at depths of 20 to 40 inches.
DRAINAGE AND PERMEABILITY: Well drained; slow to moderate runoff; slow permeability.
USE AND VEGETATION: All of this soil is used to grow small grains under a grain-fallow cropping system.
DISTRIBUTION AND EXTENT: Northeastern Oregon. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Umatilla County, Oregon, 1937.
ADDITIONAL DATA: Characterization data for one pedon, S77OR-59-1, by Oregon State University not published.