Over the last 20 years, U.S. corn yield has increased by an average of 1.7 bu/acre per year. These gains have resulted from breeding for increased yield potential, the introduction of transgenic traits to help protect yield, and agronomic management that has allowed yield potential to be more fully realized.
“Basic management practices employed by the 2013 NCGA National Corn Yield Contest winners can contribute to higher yields for all corn growers,” says Mark Jeschke, DuPont Pioneer agronomy research manager.
Selecting the right hybrid is likely the most important management decision made by contest winners. To achieve highest possible yields, growers should select a hybrid with:
- Top-end yield potential
- Full maturity for the field
- Good emergence under stress
- Above-average drought tolerance
- Resistance to local diseases
- Traits that provide resistance to major insects, such as corn borer, corn rootworm, black cutworm and western bean cutworm
- Good standability to minimize harvest losses
Improvement of corn-hybrid genetics for superior stress tolerance has contributed to increased yields by allowing hybrids to be planted at higher plant populations. Almost 75 percent of national corn-yield contest entries were between 32,000 and 39,000 plants/acre.
Winning contest plots are usually planted as early as is practical for their geography. Early planting lengthens the growing season and, more importantly, enables earlier pollination. When silking, pollination and early ear fill are accomplished in June or early July, heat and moisture stress effects can be reduced.
Rotating crops is highly recommended to keep yields consistently high. Rotation can break damaging insect and disease cycles that lower crop yields. Including crops like soybeans or alfalfa in the rotation can reduce the amount of nitrogen (N) required in the following corn crop.
Achieving the highest corn yields requires an excellent soil-fertility program, beginning with a timely application of N and soil testing to determine existing levels of phosphorous (P), potassium (K) and soil pH.
Regardless of the herbicide program used, excellent weed control (beginning before weeds compete with corn for water, light and nutrients) is essential for reaching the highest corn yields. Studies show that the critical period for preventing yield-reducing weed interference in corn is from the V2 to V3 growth stage until V12.