Importance of corn stand and emergence uniformity
Planter speed can affect both stand and emergence uniformity. Research conducted in northeast Kansas supports the conclusion that final plant population, which was reduced with higher planting speeds, had a greater impact on yield than did accompanying reductions in uniformity of plant spacing. Be sure to follow manufacturer guidelines for recommended planter speeds.
Adjust planter units to optimize seed placement and depth. Seed firmers may help place seeds more uniformly. Emergence might be delayed slightly with deeper planting, but it will likely emerge more uniformly than if it were planted too shallowly (e.g. one inch or less). This is especially true with early planting and cool soil temperatures. With warm soil temperatures and adequate, uniform moisture, corn seedlings emerge more quickly and uniformly from any depth. Regardless of soil temperature, stand and emergence uniformity generally is maximized when seed is placed between 1.5 and 2.5 inches in depth. See the January 20, 2012 e-Update for more information on how planting depth can influence emergence and stand uniformity.