LOCATION YOST WAEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Typic Haploxererts
TYPICAL PEDON: Yost clay, irrigated pasture. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 10 inches; gray (10YR 5/1) clay, very dark gray (10YR 3/1) moist; strong fine angular blocky structure that parts to strong fine and medium granular structure; wedge shaped peds have pronounced slickensides; very hard, firm, very sticky, very plastic; many roots in upper 2 inches, common below; few fine pores; mildly alkaline (pH 7.4); gradual smooth boundary. (5 to 10 inches thick)
A12--10 to 21 inches; gray (10YR 5/1) clay, very dark gray (10YR
3/1) moist; moderate medium angular blocky structure; wedge shaped peds have long axis tilted 10 to 60 degrees from horizontal and have shiny faces; distinct slickensides; very hard, firm, very sticky, very plastic; few roots; moderately alkaline (pH 8.1); weakly calcareous; gradual wavy boundary. (5 to 14 inches thick)
A13--21 to 41 inches; gray (10YR 5/1) clay, very dark gray (10YR
3/1) moist; many distinct wedge shaped peds that have their long axis tilted 10 to 60 degrees from horizontal; peds have shiny faces; distinct slickensides; very hard, firm, very sticky, very plastic; moderately alkaline (pH 8.1); gradual wavy boundary. (5 to 22 inches thick)
C--41 to 60 inches; light gray (10YR 6/1) clay, dark gray (10YR 4/1) moist; massive; very hard, firm, very sticky, very plastic; mildly alkaline (pH 8.1).
TYPE LOCATION: Yakima County, Washington; at a point 50 feet north of the Mc Donald Road and 4,200 feet east of the Bench Road in the SW1/4 SE1/4 section 32, T.11N., R.18E., WM.
RANGE IN CHARACTERISTICS: With irrigation most areas are wet or moist at all times. Nonirrigated areas have cracks 1 to 5 centimeters in width and 30 to 40 inches in depth that open and close once each year and remain open for 60 consecutive days or more during more than 7 out of 10 years. The clay content ranges from 50 to 65 percent in the 10 to 40 inch control section. The mean annual soil temperature at 20 inches ranges from 47 to 55 degrees F. The soil is mildly to moderately alkaline and noncalcareous to weakly calcareous. The A horizon has a dry value of 4 or 5, moist value of 2 to 3.5, and chromas of 1 or less. The thickness of the A horizon ranges from 20 to 40 inches. The C horizon has a dry value of 4 through 6, and a moist value of 3 through 5, and chromas of 1 or less moist or dry.
COMPETING SERIES: These are the Basnaw, Cove, Coker, and Pit soils. Basnaw soils range from slightly acid to neutral, and have yellowish red and reddish yellow mottles below 6 inches. Cove soils lack slickensides close enough to intersect, and also wedge shaped peds with their long axis tilted as much as 10 degrees from horizontal. Coker soils lack chromas of 1.5 or less to a depth of 40 inches. Pit soils lack chromas of 1.5 or less to a depth of 40 inches, and are neutral to slightly acid in the upper part of the A1 horizon.
GEOGRAPHIC SETTING: Yost soils are on nearly level bottomlands or in basins within the alluvial floodplain at an elevation of about 800 feet above sea level. These soils formed in alluvium or lake sediments. The basin areas are ponded during winter months and all areas have a seasonally high water table at or near the surface. They are in a climate with warm, dry summers and cold, moist winters and a mean annual precipitation of 6 to 9 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 include the Ahtanum, Kittitas, and Toppenish soils. These soils have medium or moderately fine textures.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; runoff is very slow; permeability is very slow.
USE AND VEGETATION: Used mainly for pasture. Vegetation consists of water tolerant plants including cattails and sedges. Vegetation of the improved pastures includes redtop, reed canary grass, creeping meadow foxtail grasses, and legumes including White Dutch clover and strawberry clover.
DISTRIBUTION AND EXTENT: South central Washington. Yost soils are inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Yakima County, Washington, 1970.
REMARKS: Yost series was formerly classified as Grumusols.