LOCATION TOPPENISH WAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Fluvaquentic Endoaquolls
TYPICAL PEDON: Toppenish silt loam, irrigated cropland. (Colors are for dry soil unless otherwise stated.)
Ap--0 to 6 inches; dark gray (10YR 4/1) silt loam, very dark gray (10YR 3/1) moist; moderate thin and medium platy structure; slightly hard, friable, slightly sticky and slightly plastic; many roots; common fine pores; slightly effervescent; moderately alkaline (pH 8.4); abrupt smooth boundary. (4 to 8 inches thick)
BA--6 to 17 inches; dark gray (10YR 4/1) clay loam, very dark gray (10YR 3/1) moist; moderate medium and coarse prismatic structure; hard, friable, sticky and plastic; many roots; common fine pores; discontinuous clay films and slickensides on surfaces of peds; slightly effervescent; moderately alkaline (pH 8.2); gradual wavy boundary. (8 to 16 inches thick)
Bg1--17 to 31 inches; light brownish gray (10YR 6/2) silt loam, grayish brown (10YR 5/2) moist; common medium prominent yellowish red (5YR 5/6) redox concentrations; moderate medium subangular blocky structure; hard, friable, sticky and plastic; few roots; few medium pores; few pebbles; mildly alkaline (pH 7.8); gradual boundary. (10 to 22 inches thick)
2Bg2--31 to 42 inches; grayish brown (10YR 5/2) very gravelly clay loam, very dark grayish brown (10YR 3/2) moist; common medium prominent dark brown (7.5YR 4/4) redox concentrations; moderate medium subangular blocky structure; hard, friable, sticky and plastic; few roots; few medium pores; 40 percent pebbles; mildly alkaline (pH 7.8); gradual wavy boundary. (2 to 12 inches thick)
3C--42 to 60 inches; brown (10YR 5/3) extremely gravelly sandy loam, dark brown (10YR 3/3) moist; massive; very friable, nonsticky and nonplastic; 80 percent pebbles; mildly alkaline (pH 7.8).
TYPE LOCATION: Yakima County, Washington; 3/4 mile south of Highway 22 and 200 feet east of the Myers road in the NW1/4 NW1/4 NW1/3 section 23, T.10N., R.20E., WM.
RANGE IN CHARACTERISTICS: Solum thickness is 40 to 56 inches. The mean annual soil temperature at a depth of 20 inches range from 47 to 55 degrees F. The soils are mildly alkaline to strongly alkaline and become less alkaline with depth. Content of coarse fragments in the control section averages 10 to 15 percent. The mollic epipedon is 10 to 24 inches thick.
The A and BA horizons have value of 4 or 5 dry, 2 or 3 moist, and chroma of 1 or 2 dry or moist. They are silt loam, silty clay loam or clay loam. They have moderate platy or moderate prismatic structure.
The Bg horizon has value of 4 through 6 dry, 3 through 5 moist, chroma of 1 or 2 dry or moist, and has common to many distinct to prominent redox features. It is silt loam or clay loam. This horizon has moderate subangular blocky or prismatic structure.
The C horizon has hue of 10YR through 2.5Y, value of 4 through 6 dry, 3 or 4 moist, and chroma of 1 through 4 dry and moist. It is sandy loam or sand, and is extremely gravelly.
COMPETING SERIES: These are the Ambraw, Ozamis, Settlemeyer and Sloan series in the same family and the Kittitas series. Ambraw and Sloan soils have firm consistence. Also, Ambraw soils are neutral or slightly acid in the upper part of the control section and Ambraw and Sloan soils are noncalcareous in all parts of the calcareous control section. Ozamis and Settlemeyer soils have sola less than 40 inches thick. Kittitas soils are calcareous in all parts of the control section.
GEOGRAPHIC SETTING: Toppenish soils are on nearly level alluvial bottomlands at an elevation of 700 to 1,800 feet. Slopes are 0 to 8 percent. They formed in mixed alluvium. These soils are in a climate with warm, dry summers and cold, moist winters. The mean annual precipitation is 6 to 10 inches. The average January temperature is 29 degrees F.; the average July temperature is 73 degrees F.; and the average annual temperature is 51 degrees F. The frost free season is 130 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Fiander, Naches, Wahtum soils and the competing Kittitas soils. Fiander and Wahtum soils have a natric horizon. Naches soils are well drained and have argillic horizons underlain by very gravelly sandy at 20 to 40 inches.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; slow runoff or ponded; moderate to moderately slow permeability in the solum and very rapid in the IIC horizon.
USE AND VEGETATION: When drained and irrigated, crops grown are corn, peas, sugar beets, hay, and pasture. In natural conditions the soil is used for the production of native pasture. Native vegetation consists of water tolerant grasses.
DISTRIBUTION AND EXTENT: South-central Washington. The soil is of moderate extent.
MLRA OFFICE RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Yakima County, Washington, 1947.