Behr also recommends planting a selection of hybrids with different maturities and genetics to help manage both the risk of summer heat stress with pollination timing and the workload at harvest. "Since we can't predict what kind of growing season we'll have, it's best to plant 25% early maturing hybrids, 50% mid-range and 25% late maturing hybrids," he adds.
The second-ranked practice in the university trials, crop rotation, affected 4% to 19% of yield. Research generally demonstrates a yield improvement for corn following soybeans or alfalfa. However, some growers take advantage of the high yield potential that continuous corn can offer when prices are right.
A relatively small percentage of Jay's fields are continuous corn, but he understands the extra steps needed when selecting hybrids. "You really have to be particular with your corn-on-corn hybrids," he says. "Some are stronger, can withstand the stress and have better disease resistance. We manage those acres a lot more carefully, not just with the hybrids we select, but also applying fungicides and other practices."
Management decisions that make a difference
Rank % Yield Impact Agronomic Factor*
1 37-64 Hybrid selection
2 4-19 Crop rotation vs. continuous corn
3 6-15 Tillage system for continuous corn
4 6 Uniform emergence vs. 1-leaf stage delay
5 4 Late- and mid-season hybrids vs. early hybrids
The next four factors had much less impact on performance:
6 2-5 Planting date
7 1-2 Population of 34,000 vs. 30,000 plants/acre
8 1-2 Within row plant spacing
9 0-4 Narrow or twin rows vs. 30-inch rows
*Two factors not mentioned are soil fertility and insect and disease management. Researchers considered these to be prerequisites for high yield corn. Courtesy of University of Minnesota.