One of the Corn Illustrated plots near Edinburgh, Ind., this year present a classic example demonstrating that you can push populations further on some hybrids than others. Push some too far and they will cry 'uncle,' either by leaving more stalks barren, dropping ears before harvest, falling over prematurely, or any combination of these. Other hybrids can handle the stress of more plants without showing these visible symptoms, although that doesn't necessarily mean pushing them to high populations is necessary, profitable or the right thing to do.
In this particular plot, two hybrids were planted in three row configurations- 30-inch standard rows, 15-inch rows, and twin- 5-inch rows on 30-inch centers, and thinned to three populations for the twin-rows and 15-inch rows. Harvest populations taken last week for the three levels turned out to be approximately 32,000, 40,000 and 55,000, respectively. Harvest population in all 30-inch conventional row plots was 32,000- higher rates were not tried there.
Hybrid A handled all three population levels reasonably well, at least as far as stalk lodging goes. There was some lodging at the medium, 40,000 plants per acre level, and slightly more at 55,000, but as of last week, lodging for Hybrid A wasn't severe.
For hybrid B on the other hand, there was comparable lodging to hybrid A at 32,000 and 40,000 plants per acre. But at 55,000 in both twin rows and 15-inch rows, it was 'Katie bar the door' – lodging was rampant. It was so serious that one could judge which hybrid was which at the highest population, walking across the plot, just by viewing the stalk lodging, notes Dave Nanda, president of Bird Hybrids, LLC., Tiffin, Ohio, and consultant for the Farm Progress Corn Illustrated project.
Nanda wasn't surprised by the difference, noting that some hybrids handle stress better than others, and that various hybrids have different points at which they can no longer tolerate a certain type of stress. "What will be interesting will be waiting and seeing yield results for these various plots," Nanda notes. "The yield results may not necessarily match up with the amount of lodging by the two hybrids under different populations and row spacing."
Harvest is not expected until mid-to-late October. The plot was planted the last week of May, due to weather delays, and maturity was delayed by s cooler-than-normal summer. Watch for results to appear here once plots are harvested.