LOCATION CURANT OREstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Calcic Pachic Haploxerolls
TYPIFYING PEDON: Curant silt loam, range. (Colors are for moist soil unless otherwise noted.)
A11--0 to 4 inches; very dark brown (10YR 2/2) silt loam, dark gray (10YR 4/1) dry; weak thin and medium platy and weak fine granular structure; slightly hard, very friable, slightly sticky, slightly plastic; many very fine roots; many very fine irregular pores; neutral (pH 6.6); abrupt smooth boundary. (2 to 4 inches thick)
A12--4 to 16 inches; very dark brown (10YR 2/2) heavy silt loam, dark gray (10YR 4/1) dry; weak coarse prismatic and moderate medium subangular blocky structure; hard, friable, slightly sticky, slightly plastic; many very fine roots; many very fine tubular pores; neutral (pH 6.8); clear wavy boundary. (6 to 12 inches thick)
B2--16 to 25 inches; dark brown (10YR 3/3) heavy silt loam, brown (10YR 5/3) dry; weak medium and coarse prismatic and moderate subangular blocky structure; hard, friable, sticky, slightly plastic; many very fine roots; many very fine tubular pores; few thin very dark brown coatings on peds; few dark krotovinas; neutral (pH 7.0); clear wavy boundary. (5 to 15 inches thick)
B3--25 to 33 inches; dark brown (10YR 3/3) silt loam, brown (10YR 5/3) dry; weak coarse prismatic and weak medium subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic; many very fine roots; many very fine tubular pores; few hard nodules 1/2 to 1 inch in diameter; few dark krotovinas; neutral (pH 6.8); clear wavy boundary. (6 to 12 inches thick)
IIC1--33 to 39 inches; brown (10YR 4/3) silt loam, pale brown (10YR 6/3) dry; massive; slightly hard, very friable, slightly sticky, slightly plastic; common very fine roots; many very fine pores; 5 percent pebbles; mildly alkaline (pH 7.6); clear wavy boundary. (0 to 10 inches thick)
IIC2ca--39 to 60 inches; brown (10YR 4/3) silt loam, pale brown (10YR 6/3) dry; massive; slightly hard, very friable, slightly sticky, slightly plastic; few very fine roots; many very fine pores; 15 percent pebbles; strongly calcareous with light gray segregations of lime; moderately alkaline (pH 8.2).
TYPE LOCATION: Wasco County, Oregon; 200 feet east of farm road in the NE1/4 NW1/4 NW1/4 sec. 25, T.8S., R.16E.
RANGE IN CHARACTERISTICS: In most years the soils are usually moist but dry throughout between depths of 4 and 12 inches for 70 to 90 consecutive days within the 3-month period following the summer solstice. The mean annual soil temperature ranges from 49 degrees to 53 degrees F. The solum ranges from 30 to 40 inches thick. A few rock fragments may occur in the sola, up to 30 percent in that part of the C horizon above 40 inches and up to 60 percent below. The weighted average of material coarser than very fine sand within the control section is less than 15 percent. The soils range from neutral in the sola to mildly and moderately alkaline in the C horizon. The a horizon has value of 4 or 5 dry and 2 or 3 moist, and chroma of 1 or 2 moist and dry. It has 0 to 5 percent pebbles. The B2 horizon has value of 5 or 6 dry and 3 or 4 moist, with value of 3 moist and 5 dry to depths of 20 inches or more. It is heavy silt loam to light silty clay loam with 20 to 30 percent clay and 0 to 20 percent pebbles. The B3 and IIC horizons above 40 inches range from silt loam, or very fine sandy loam, to loam with 10 to 35 percent pebbles. They are moderately or strongly calcareous.
COMPETING SERIES AND THEIR DIFFERENTIAE: These are the Asotin, Condon, Snow, and Walla Walla series. Asotin and Condon soils have mollic epipedons less than 20 inches thick and are 20 to 40 inches deep to bedrock. Snow soils have an irregular decrease in organic material and lack secondary lime within 60 inches. Walla Walla soils have less than 18 percent clay in the control section.
SETTING: Curant soils are at elevations of 2,200 to 3,700 feet on north aspects of moderately steep to very steep slopes. These soils formed in loess over mixed medium and moderately coarse textured old alluvium or colluvial material from sedimentary and igneous rocks of mixed mineralogy. The climate is semiarid with hot dry summers and cool moist winters. Average annual precipitation is 10 to 14 inches. The mean annual temperature is 45 degrees to 49 degrees F.; the mean winter temperature is 31 degrees to 35 degrees F., and the mean summer temperature is 62 degrees to 64 degrees F. The average frost-free period (32 degrees F.) is approximately 50 to 70 days.
PRINCIPAL ASSOCIATED SOILS: These are the Day, Degner, McMeen, Tub, and Rail soils. Day soils are very fine textured throughout. Degner and Tub soils have clayey argillic horizons. McMeen soils have duripans. Rail soils have more than 35 percent clay throughout the solum and are somewhat poorly drained.
DRAINAGE AND PERMEABILITY: Well-drained; medium to rapid runoff; moderate permeability.
USE AND VEGETATION: Principal use is grazing. Other uses are wildlife and recreation. Grasses are Idaho fescue, bluebunch wheatgrass and Sandberg bluegrass. Forbs are yarrow, lupine, arrowleaf balsamroot, carrot and milkvetch. Brush plants are rose, wax currant and traces of serviceberry, snowberry and chokecherry.
DISTRIBUTION AND EXTENT: In Wasco, Wheeler, and Jefferson Counties in central Oregon within the Upper John Day, Crooked and Malheur River Plateau Land Resources Area. The series is moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Wasco County (Trout Creek-Shaniko Area), Oregon, 1970.
REMARKS: The Curant soils were formerly classified as Chestnut soils.
ADDITIONAL DATA: Laboratory data on 1 pedon (S68-33-1) from Oregon State University Laboratory.