LOCATION STANFIELD OR+WAEstablished Series
TAXONOMIC CLASS: Coarse-silty, mixed, superactive, mesic Aquic Haplodurids
TYPICAL PEDON: Stanfield silt loam, cultivated. (Colors are for dry soil except as noted.)
Ap--0 to 6 inches; light brownish gray (10YR 6/2) coarse silt loam, dark grayish brown (10YR 4/2) moist; weak medium granular structure; slightly hard, very friable, nonsticky and slightly plastic; common very fine roots; many very fine irregular pores; slightly effervescent, with disseminated lime; moderately alkaline (pH 8.4); abrupt smooth boundary. (3 to 10 inches thick)
ACk--6 to 13 inches; light brownish gray (10YR 6/2) coarse silt loam, brown (10YR 4/3) moist; massive; slightly hard, very friable, nonsticky and slightly plastic; common very fine roots; many very fine pores; strongly effervescent, with disseminated lime; strongly alkaline (pH 9.0); gradual irregular boundary. (0 to 30 inches thick)
Ck--13 to 22 inches; pale brown (10YR 6/3) coarse silt loam, brown (10YR 4/3) moist; massive; slightly hard, very friable, nonsticky and slightly plastic; few very fine roots; many very fine and few fine pores; few grayish brown to very dark grayish brown when moist, calcareous firm nodules 1/4 to 1 inch in diameter; strongly effervescent, with disseminated lime; very strongly alkaline (pH 9.4); abrupt wavy boundary. (0 to 30 inches thick)
2Ckqm--22 to 41 inches; pale brown (10YR 6/3) coarse silt loam, brown (10YR 4/3) moist; massive; hard and very hard, very firm, nonsticky and nonplastic; strongly cemented hardpan with indurated silica coating on surface and in some pores; few very fine roots; many very fine pores; strongly effervescent, with disseminated lime; very strongly alkaline (pH 9.6); clear wavy boundary. (4 to 30 inches thick)
3Ck--41 to 58 inches; light brownish gray (10YR 6/2) coarse silt loam, brown (10YR 4/3) moist; massive; slightly hard, very friable, nonsticky and slightly plastic; few very fine roots; many very fine and few fine pores; strongly effervescent, lime mainly disseminated; moderately alkaline (pH 8.4); abrupt smooth boundary. (10 to 30 inches thick)
4Ckqm--58 to 70 inches; light brownish gray (10YR 6/2) silt loam, dark grayish brown (10YR 4/2) moist; massive; very hard, very firm, nonsticky and slightly plastic; strongly cemented with silica coating on surface and in some pores; many very fine and few fine pores; strongly effervescent, with mycelial lime; moderately alkaline (pH 8.4); clear smooth boundary. (0 to 24 inches thick)
5C--70 to 86 inches; light brownish gray (10YR 6/2) silt loam, very dark grayish brown (10YR 3/2) moist; massive; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and common fine pores; few fine distinct reddish brown (5YR 4/4) mottles; mildly alkaline (pH 7.4). (0 to many feet thick)
TYPE LOCATION: Umatilla County, Oregon; about 600 feet east of section line fence and 55 feet north of road, SW1/4 SW1/4 sec. 17, T. 3 N., R. 28 E.
RANGE IN CHARACTERISTICS: The mean annual soil temperature ranges from 49 to 55 degrees F. The soils are usually dry but are moist during the winter season and in some part of the soil between depths of 8 and 24 inches for a period equal to more than 1/4 of the time that the soil temperature exceeds 41 degrees F. The soils range from very strongly alkaline to moderately alkaline. The percentage of exchangeable sodium decreases from the upper 10 inches to the underlying subhorizon. The 10- to 40- inch control section is very fine sandy loam, silt loam or loam and has less than 18 percent clay, less than 15 percent coarser than very fine sand and no rock fragments. Depth to bedrock is greater than 60 inches and typically 10 feet or more.
The A and AC horizons have value of 5.5 through 7 dry, 3.5 or 4 moist and chroma of 2 or 3 moist and dry. The A horizon is strongly or very strongly alkaline. Under irrigation the surface may become sodic and noncalcareous.
The C horizon has hue of 10YR or 2.5Y, value of 3 or 4 moist, 6 or 7 dry and chroma of 2 or 3 moist or dry.
The duripan is strongly cemented to indurated but is indurated in some part and depth to the pan ranges from about 20 to 40 inches. Although the pan ranges from 4 to 30 inches in thickness it is commonly 7 to 20 inches thick. In some pedons there are a series of pans with friable horizons between pans. Layers of volcanic ash commonly about 12 inches thick but ranging to several feet in thickness are just above or just below the pan in some pedons. Also, in some pedons a small amount of mica is scattered throughout the profile, but the greatest amount is below the first pan.
COMPETING SERIES: These are the Burke and Minidoka series. Burke soils are mildly or moderately alkaline throughout and formed in shallow deposits of loess. Minidoka soils have a calcic horizon, lack volcanic ash and are well drained.
GEOGRAPHIC SETTING: Stanfield soils are on nearly level low terraces and bottomlands at elevations of about 300 to 3,500 feet. The soils formed in very deep loess-derived alluvium with an appreciable amount of volcanic ash. Slopes are 0 to 3 percent. The climate is semiarid with mean annual precipitation of 8 and 12 inches, warm dry summers and cool, relatively moist winters. The mean January temperature is 29 degrees F., mean July temperature is 70 degrees F., mean annual temperature is 47 to 53 degrees F. The frost-free season is 120 to 195 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Burke soils and the Powder, Ritzville, Shano and Umapine soils. Powder soils are deep well drained bottomland soils lacking a duripan. Ritzville and Shano soils are deep well drained upland soils lacking a duripan. Umapine soils lack a duripan and are somewhat poorly drained.
DRAINAGE AND PERMEABILITY: Moderately well drained; slow runoff; moderate permeability through horizons above the duripan and very slow through the duripan. With irrigation, some areas have a higher water table and are flooded for brief periods.
USE AND VEGETATION: Major uses are irrigated and dryland pasture. Principal native plants are saltgrass, giant wildrye and greasewood.
DISTRIBUTION AND EXTENT: Northeastern Oregon and eastern Washington. The series is moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Umatilla Area, Oregon, 1940.
ADDITIONAL DATA: Data for this pedon from Oregon State University S62-Ore. 30-1-(1-7); data near type location S79-OR-59-4-(1-6).
NATIONAL COOPERATIVE SOIL SURVEY USA
NSTH 17, RECLASSIFICATION ONLY, 3/95