These lower populations should be considered on soils low in fertility, susceptible to drought, imperfectly drained, or otherwise in poor condition. An increase in plant density is most likely to result in improved grain yield in fields that already have a history of high yields with little lodging. In such cases, consideration should be given to increasing plant population. There appears to be little advantage to plant densities over 67,000 plants per hectare for grain corn. A benefit from higher plant densities will most likely be obtained when corn is planted early.
Later plantings result in large, leafier plants and more inter-plant competition.
Therefore, plant density should be reduced as planting is delayed. Because lodging is of less concern in corn grown for whole-plant silage, higher plant populations can be used than for grain corn. In areas with less than 3100 heat units, final stands of 60,000 to 70,000 plants per hectare will produce higher silage yields with little effect on the grain content or moisture level of the silage. These populations should be used only where it is certain that the field will be harvested for whole-plant silage. Fields left for grain at these densities could lodge excessively.