LOCATION MCCURDY OREstablished Series
TAXONOMIC CLASS: Fine, isotic, mesic Oxyaquic Palehumults
TYPICAL PEDON: McCurdy silt loam, on a plane slope of 8 percent in pasture at 300 feet elevation. (Colors are for moist soil unless stated otherwise.)
Ap--0 to 7 inches; dark brown (7.5YR 3/4) silt loam, yellowish brown (10YR 5/4) dry; moderate fine and very fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many fine and very fine roots; common fine irregular pores; strongly acid; clear wavy boundary. (6 to 16 inches thick)
BA--7 to 12 inches; dark brown (7.5YR 4/4) silty clay loam, yellowish brown (10YR 5/4) dry; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common fine and very fine roots; common fine irregular pores; very strongly acid; clear wavy boundary. (0 to 9 inches thick)
Bt1--12 to 20 inches; dark yellowish brown (10YR 4/6) silty clay loam, yellowish brown (10YR 5/6) dry; moderate medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common fine and very fine roots; few fine and medium irregular and tubular pores; common distinct clay films on peds and in pores; very strongly acid; clear wavy boundary.
Bt2--20 to 34 inches; yellowish brown (10YR 5/8) silty clay loam, brownish yellow (10YR 6/8) dry; moderate medium subangular blocky structure; hard, firm, sticky and plastic; few fine and very fine roots; few medium tubular pores; common distinct clay films on peds and in pores; few medium distinct light olive brown (2.5Y 5/4) masses of iron accumulation; very strongly acid; clear wavy boundary. (Combined Bt horizon is 14 to 30 inches thick).
BC--34 to 48 inches; yellowish brown (10YR 5/8) silty clay loam, yellow (10YR 7/8) dry; weak coarse subangular blocky structure; hard, firm, sticky and plastic; few fine and very fine roots; few medium tubular pores; many medium distinct light brownish gray (2.5Y 6/2) iron depletions; very strongly acid; clear wavy boundary. (0 to 15 inches thick)
C--48 to 60 inches; brownish yellow (10YR 6/8) silty clay loam, yellow (10YR 7/8) dry; massive; very hard, firm, sticky and plastic; many medium distinct light gray (N 6/0) and light brownish gray (2.5Y 6/2) iron depletions; very strongly acid.
TYPE LOCATION: Coos County, Oregon; about one mile southwest of Gaylord; 2,600 feet south and 600 feet east of the NW corner of section 27, T. 30 S., R. 12 W.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 50 to 55 degrees F. Solum thickness is 35 to 60 inches. The soil is usually moist but is dry for less than 45 consecutive days in the summer. Redox depletions with chroma of 2 or less are at a depth of 26 to 36 inches. The soil is strongly acid or very strongly acid. Stratified gravelly alluvial material is commonly below 60 inches.
The A horizon has hue of 5YR to 10YR, value of 3 or 4 moist, 4 or 5 dry, and chroma of 2 to 4 moist and dry.
The Bt horizon has hue of 10YR or 7.5YR, value of 4 or 5 moist, 5 to 7 dry, and chroma of 6 to 8 moist and dry. Redox concentrations have hue of 10YR or 2.5Y. It is silty clay loam or silty clay with 35 to 50 percent clay.
The C horizon has hue of 10YR or 7.5YR, value of 4 to 6 moist, 4 to 7 dry, and chroma of 4 to 8 moist and dry. Redox concentrations have hue of 2.5Y or 10YR. It is silty clay loam, silty clay, or clay.
COMPETING SERIES. This is the Cumley series. Cumley soils have mottles with chroma of 2 or less in the lower part of the argillic horizon and have moist chroma of 3 or 4 in the Bt horizon.
GEOGRAPHIC SETTING: McCurdy soils are on high terraces of the Dolph geomorphic surface. They formed in mixed alluvium. Slopes are dominantly 8 to 15 percent but range from 0 to 30 percent. Elevation is 100 to 800 feet. The climate is characterized by cool wet winters and warm moist summers. The mean annual precipitation is 60 to 100 inches, mean annual temperature is 49 to 53 degrees F., and the frost-free period is 145 to 240 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Chismore, Dement, Eilertson, Etelka, Meda, and Pyburn. Chismore soils are on adjacent low stream terraces and are mottled above 20 inches. Dement, Etelka, and Meda soils occur on adjacent uplands. Dement, Eilertson and Meda are well drained. Etelka soils lack an argillic horizon. Pyburn soils are on adjacent low stream terraces and are poorly drained.
DRAINAGE AND PERMEABILITY: Moderately well drained; moderately slow permeability. A seasonal water table is as high as a depth of 2.0 to 3.0 feet below the soil surface from November through April.
USE AND VEGETATION: McCurdy soils are used for pasture. Some areas are used for timber production, wildlife habitat, and homesites. The native vegetation is Douglas fir, Port Orford cedar, grand fir, western redcedar, red alder, willow, tanoak, Oregon white oak, Pacific rhododendron, salal, salmonberry, western brackenfern, western swordfern, evergreen huckleberry, trailing blackberry, and vine maple.
DISTRIBUTION AND EXTENT: Along streams in the interior valleys of western Oregon; MLRA 1. The series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Coos County, Oregon, 1983.
REMARKS: Diagnostic horizons and features of this pedon include:
Argillic horizon - 12 to 34 inches (Bt1 and Bt2 horizons).
Pale feature - percentage of clay does not decrease from its maximum amount by 20 percent or more within a depth of 60 inches from the soil surface.
This series has been reclassified from clayey, mixed, mesic Typic Haplohumults to clayey, mixed, mesic Typic Palehumults based on addition of Palehumults to Soil Taxonomy.