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Little is known about K fertility management for no‐till (NT) soybean [Glycine max (L.) Merr.]. This study was conducted to evaluate the residual effects of K application rate, timing, and placement for corn (Zea mays L.) in various tillage systems on subsequent NT soybean. Field experiments involving a corn–soybean rotation were conducted from 1998 to 2000 on long‐term NT fields with medium or high exchangeable soil K levels near Kirkton and Belmont, ON, Canada. In the corn year, treatments included the combinations of three fall K rates (0, 42, and 84 kg ha⁻¹), spring K rates (two rates differing by 42 kg ha⁻¹), and three tillage systems [NT, zone till (ZT), and moldboard plow (CT)]. Both CT and ZT (also known as intermittent tillage systems) reduced soil K stratification relative to continuous NT. Trifoliate leaf K concentrations increased with residual fall and spring K applications in most site‐years. Average …