The mean annual precipitation is 8 to 12 inches. The frost free period is 110 to 140 days. These are the Cullius , Era , and Madras soils. Cullius soils are on terraces and plateaus and are shallow with a clayey argillic horizon. Era soils are in swales and uplands and are deep and coarse-loamy.
Madras are on terraces and plateaus and have a fine-loamy argillic horizon.
These soils are used for irrigated cropland, pasture, and livestock grazing. Potential native vegetation is western juniper, basin big sagebrush, antelope bitterbrush, bluebunch wheatgrass, and Idaho fescue. The series is moderately extensive. Interbedded basalts and ash-flow tuffs are included in this formation. Partial laboratory data are available for this soil.