Choosing hybrids for their ability to overcome the stresses in individual fields is several steps removed from simply looking at neighborhood plots and talking to neighbors, says Farm Journal Field Agronomist Ken Ferrie. Here some tips to keep in mind:
- The general rule of pendulum-leaf, flex-ear hybrids and lower populations for droughty soils holds true regardless of row width.
- When evaluating neighborhood hybrid plots, learn about the field and growing conditions. “An upright-leaf hybrid of fixed-ear format that topped a plot with a high population looks appealing,” Ferrie says. “But if the plot’s soil supplied twice as much water as your field, you won’t get the same results.”
- Plant your own test plots and compare new hybrids to those you know well. Study plant and leaf structure—are hybrids taller or shorter, upright-leaf or pendulum? Photograph plants side by side and use the photos for later comparison.
Hybrid Selection Pays Big
Ferrie’s advice is based on Farm Journal studies comparing plant structure, leaf structure and ear-flex characteristics. He planted replicated strips of shorter, upright-leaf hybrids with more fixed ear size and taller, pendulum-leaf hybrids with flexible ear size in fields containing zones of light, droughty soil intermingled with highly productive soil that yields well even in dry years.
Previous studies showed the tall, pendulum-leaf hybrid stopped responding to increased population between 30,000 and 32,000 plants per acre, indicating all sunlight was being captured. The shorter, upright-leaf hybrid stopped responding to population at 35.000 to 37,000, showing it captured more light as the population went up because of its plant height and leaf structure.
In the 2021 hybrid characteristics study, Ferrie planted shorter, upright-leaf hybrids and taller, pendulum-leaf hybrids at 32,000 and 35,000 plants per acre and compared their performance in droughty and highly productive soils.
- The tall, pendulum-leaf hybrid yielded best at 32,000 plants per acre in both soil types, indicating full canopy was reached, and 97% of sunlight intercepted, at that population.
- In the droughty soil, pushing population of the tall, pendulum-leaf hybrid from 32,000 to 35,000 lowered profit by $20 per acre. In the highly productive soil, that same population increase reduced profit by $57 per acre. “In both management zones, increasing population of that hybrid increased stress,” Ferrie says.
- With the short, upright-leaf hybrid, in droughty management zones, pushing population from 32,000 to 35,000 reduced profit by $17 per acre. “That indicates there was not enough available water to support the increased population,” Ferrie says.
- In the droughty soil, when the tall, pendulum-leaf hybrid was planted at 32,000 plants per acre, it produced $125 more profit per acre than the short, upright-leaf hybrid at 35,000 plants per acre. “The lower plant density made more water available for each plant,” Ferrie says. “The tall, pendulum-leaf hybrid’s ability to flex ear size to make up for lower ear count compensated for the lower population.”
- When the shorter, upright-leaf hybrid was planted in highly productive soil, pushing the plant population from 32,000 to 35,000 increased revenue by $42 per acre above seed cost.
- In highly productive soil, planting both hybrids at 35,000 resulted in $77 more profit per acre from the short, upright-leaf hybrid.
“When planting taller, pendulum-leaf hybrids, populations need to stay in the lower range, even on good ground,” Ferrie summarizes. “When planting shorter, upright-leaf hybrids, populations need to be pushed in good ground, to capture all available sunlight and make more yield. But short, upright-leaf hybrids at high populations may not be your best choice on soil where water is short.
“When we select hybrids based on leaf structure and ear flex characteristics, we’re picking each hybrid with a particular field in mind, to handle the stress the field will throw at it. This is an altogether different level of management from simply picking high yielders off plot data.”
