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High-yielding corn comes with a price

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By David Harrison

The increased costs of seed, fertilizer, fuel and land rents have caused many farmers to consider cutting costs in corn production, however, it is also a good time to review the concepts of producing high yields.

There are five keys to high corn yields: good genetics; maximize days suitable for growing; achieve 90 to 95 percent light interception at or close to silking stage; adequate nutrients to complete plant growth and seed fill; and adequate water and air to complete plant growth and seed fill. Most of these you have some control over. By optimizing each of these five keys, the odds for producing high corn yields are much improved.

Good hybrid genetics start with a high-yielding hybrid and includes stress tolerance and defensive traits, such as disease tolerance. The best measuring stick we currently have for stress tolerance is yield over multiple locations. Different stresses are imposed at each location and hybrid performance across locations is a good indicator of general stress tolerance.

Disease tolerance is not necessary every year or in every field and is difficult to evaluate. Seed companies do their best to provide accurate disease information, but hybrids will sometimes perform differently in the field. Traits such as Bt and multi-trait varieties by themselves do not guarantee high yields. These traits must be in hybrids that have excellent yield potential.

Maximizing days suitable for growing includes selecting the proper hybrid maturity, timely planting and finding hybrid with excellent stress tolerance. Hybrids that mature in about 113 to 117 days typically perform the best in Kentucky. Exceptions do occur, however. Optimal planting dates are middle to late April locally.

Achieving 90 to 95 percent light interception at or close to silking (R1) is affected by seeding rate, row spacing, planting date, hybrid maturity, adequate nutrients and proper weed management.

Current UK recommendations will accomplish maximum light interception close to silking. Those recommendations include seeding rates between 22,000 and 30,000 seeds per acre, a row spacing of 30 inches, timely planting, hybrid maturities of 113 to 117 days and good early season weed control.

Providing adequate nutrients, water and air to the soil to complete plant growth and seed fill includes adjusting soil pH, precipitation, water infiltration and water availability and adding the proper amount of nitrogen, phosphorus, potassium and zinc. A soil test is required for accurate adjustments of most soil nutrients. Soil type and previous crop determine the range of nitrogen necessary for high yields.