Northeast Research and Demonstration Farm
Producers continually question whether they should be increasing corn plant populations based on planting date, soil/weather conditions, and seed company recommendations. Previous high corn yield award winners have claimed that they have used deep tillage and high populations in highly fertile soils to garner their award winning yields. Improvements in genetic traits and seed treatments and in-plant protection from a number of insects have been the main selling points to increase planting populations. Advances in planting equipment (narrow and twin row configurations providing more equidistant plant spacing) have also made increasing plant populations possible. Yield increases for row spacing less than 30 in. (15 in. and twin rows) at Nashua have shown small and inconsistent yield differences with the main yield benefit being from variety selection and to a lesser extent, planting population for increasing grain yields. These trials were designed to collect information to aid in local recommendations.
Iowa State University
Pecinovsky, Kenneth T., "Corn Population Research" (2011). Iowa State Research Farm Progress Reports. 247.