Managing Plant Population for Corn in Minnesota

Abstract

With tight profit margins caused in part by recent increases in the cost of seed, it is critical that corn (Zea mays L.) producers utilize best production practices on all of their acres in order to remain economically competitive. Thus, there is a need to monitor the response of corn grain yield to plant population for new hybrids, and to determine whether this response interacts with agronomic factors. From 2005 to 2008, experiments were conducted 16 following soybean [Glycine max (L.) Merr.] at Lamberton and Waseca, MN to determine whether the response of corn grain yield to plant population was influenced by planting date, row width, or crop relative maturity. Averaged across locations, the response of grain yield to plant population was not affected by planting date or row width, but 94- to 96-day corn hybrids had an economically optimum final plant population that was 3,200 plants/acre higher than that of 102-day hybrids at a corn price of $3.50/bushel and a seed cost of $250/80,000 seeds. Averaged across all experiments, the plant population needed to maximize profitability ranged from about 32,000 to 34,000 plants/acre under current economic conditions. Yield increases resulting from higher plant populations were related to increased light interception during grain fill by the crop canopy.