To reach maximum yields, you have to minimize the stress on a corn plant. As Farm Journal Field Agronomist Ken Ferrie puts it: Keep corn happy and never let it have a bad day.
In the quest for top yields, several variables come into play.
"In many test plots, we've just pushed populations higher to see what the outcome is,” Ferrie says. "Not only do some hybrids flatline, they go backward.”
For three years, the Farm Journal Test Plots team studied hybrid response to nitrogen (N) stress with various timed applications. Working with AgriGold Hybrids, we were able to confirm their recommendations for N timing according to hybrid family.
In 2009, we continued our work with AgriGold and launched a new plot to learn more about stress on corn plants categorized by ear type.
"We look at their pedigrees and study parent lines in and out of the field to know as much as we can about a hybrid's genetic characteristics,” says Mike Kavanaugh, AgriGold agronomy manager.
Ear types. Based on the genetic characteristics, seed companies can place hybrids in one of three categories: those that will flex the most, semi-flex and those that will flex the least.
"Every hybrid flexes, but how they flex varies,” Ferrie says. "Some flex in length, some flex in girth and most just flex in kernel depth so you get a bigger ear with the same amount of kernels.”
One of the factors farmers consider when deciding to replant is ear type.
"Farmers know that if they lose stand, a flex hybrid will fill in those gaps,” Ferrie says. "However, if a fixed ear type loses plant count, it won't be as easy for it to pick up the slack.”
Ferrie has observed that even though a flex ear can maintain its yield despite stand loss, plant stress seems to take a toll on these types of hybrids.
"When we work with population plots and push plant densities from too low to too high, the determinant hybrids climb and top out in yield and then flatten until they go down in yield,”
- Late Spring 2010