Corn Yield Resonse to Nitrogen Rate and Plant Population.

Corn yield response was measure for two different plant populations and five nitrogen rates in both a corn-corn and soybean-corn rotation at Northwest Agricultural Research Station, OARDC located near Custer OH for the 2006 through 2011 growing seasons. The two population rates were 30,000 and 40,000 plants per acre. Total season nitrogen rates were 0, 60, 120, 180 and 240 pounds per acre. Forty pounds of nitrogen per acre was applied as starter and the balance of the rate applied at sidedress using anhydrous ammonia. Preliminary summary shows the highest yield responses were in the soybean-corn rotations with the highest yield from the 40,000 plants per acre population. The 180 pound nitrogen rate averaged 177.3 bushel per acre for the 40,000 population and the 30,000 population at the same nitrogen rate yielded 167.9 bushels per acre. The corn-corn rotation with the 40,000 plant population yielded nearly the same as the 30,000 soybean-corn rotation. The corn-corn 40,000 plant per acre yielded 166.9 bushels per acre at the 180 pound N per acre. The lowest yielding plot at the 180 pound rate was the corn-corn at 155 bushels per acre.