Caption: Stress wheel demonstrates different row spacing at the Syngenta Grow More™ Experience site in Stanton, MN.

Growers are always working to maximize yield – experimenting with different hybrids, traits and management practices to find what best suits fields. Often, increasing plant populations is a method growers use, with the idea being more seeds per acre means more plants with harvestable ears and consequently more yield. This can be true for some hybrids, but not all. Each hybrid has a different response to population density.

To display the effects of density on hybrids, the Syngenta Grow More™ Experience site in Stanton, MN, featured a “stress wheel” in 2017. This demonstration is a hand-planted plot of different hybrids at altered plant populations and row spacings. The plant populations ranged from 28,000 to 50,000 kernels per acre. Planting hybrids at varying row spacing demonstrates how population can affect stalk quality, ear retention, lodging, roots and ultimately, yield.

It was clear from the stress wheel results that not all hybrids are equipped to handle high populations. As population increased, some hybrids, particularly determinant ear types, faced weakened stalk strength and standability. When using these products, be cautious when increasing plant population. In general, yield increases resulting from higher plant populations are primarily due to more plants per acre capturing sunlight during the growing season. If plants become too crowded, they have smaller root systems and smaller stalks, resulting in poor standability and lower yields.

On the other hand, some hybrids respond well to higher planting populations. Such hybrids held ear size fairly well and maintained ear count. For hybrids that respond well to increased population densities, traditionally ear flex products, planting higher populations can help you reach higher yields.

When planning planting populations that are right for your fields and management style in 2018, contact your Syngenta representative or NK^® retailer with questions or for additional agronomic insights. Population recommendations are provided for all NK hybrids.

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