However, the yields of well-fertilized corn do not fall off very sharply when population is above the optimum, even in dry years . The number of ear bearing plants is usually more important than the weight of the ears. Another indicator of too high a population is an abnormal number of barren plants. Typical harvested plant population recommendations for corn in Wisconsin range between 28,000 and 32,000 plants per acre. If your fields have lighter soils then 26,000 plants per acre is about right.
Hybrids react differently, so check with the seed company.
They know the population tolerances of their hybrids and make recommendations accordingly. The effects of high plant population for corn silage production are less important because lodging is less of a concern. Even higher plant populations could obtain higher yield of green weight, but this practice produces little advantage in dry weight. Typically grain yield decreased drastically at these extremely high plant populations. Many workers have reported consistent dry matter yield increases with increasing plant population.