SITUATION

FACTORS TO CONSIDER

• Ear type of hybrid
• Row width
• Yield environment of the field
• Limitations of very high populations
• Planting date

ACTION PLAN

1. Identify the hybrid's ear style. Proper planting population partially depends on the ear type of a hybrid. A hybrid with a determinate ear requires higher populations to achieve top yield, whereas a hybrid with a flex ear may produce lower yields when planted at a high population. Planting populations for hybrids with semi-flex ears tend to vary based on the degree of ear flexibility. Consulting technical production information or a trusted agronomic adviser can help you determine the optimum population for each of your selected hybrids.
2. Recognize the impact of row width. Leaving 4½ inches between plants provides greater opportunity for proper root development, and this spacing is especially critical in high-stress environments. Seed-to-seed spacing requirements justify fewer plants in wider rows compared with narrow rows or twin rows.
3. Observe the yield environment. In addition to the hybrid characteristics, the yield environment dictates the ideal number of plants per acre. Higher plant populations are preferred in a high-yield environment with a uniform and favorable soil texture. In a low-yield environment with variable soil types, lower plant populations are acceptable. If the opportunity exists to vary the rate within a field, consider planting higher populations in high yield environments and lower populations in low yield environments.
4. Realize having more plants per acre isn't always better. More plants per acre does not necessarily maximize yield. Often, true flex-ear-type hybrids that are planted at extremely high populations can result in more plants with barren stalks and shrunken ears. In general, populations should not exceed the capacity of the yield environment. For example, in irrigated fields where moisture is not a limiting factor, the yield environment can handle a higher population compared with areas where rainfall is less predictable.
5. Understand how the planting date can impact populations. Because early planting dates can put more stress on seedlings than later planting dates, a higher seeding rate may be needed if corn is planted before conditions are ideal for emergence and optimum yield potential. Consideration also should be given for uniform planting depth. All plants should emerge at about the same time for optimum yield performance.

SUMMARY