Corn and soybean seeding rates have headed different directions in recent years. While corn population recommendations typically are higher on more productive soils and lower on less productive ones, soybeans flip that script.
“On lower-producing soils, we have increased populations,” says Doug Frazier, who farms with his uncle and father near Van Horne, Iowa. Meanwhile, they’ve lowered them on good soils in the past decade.
“I think part of that has to do with soybean germination being way better than it used to be,” he says. “Germination rates used to be around 80%, and now they’re at around 95%. This leads to planting lower populations and saving money on seed.”
Variable-rate seeding
Knowing which populations to plant on specific field areas also has led Frazier and his family to shift to variable-rate seeding.
“By putting the right number of plants out on all types of soils, you're guaranteeing the accurate rate every time,” he says.
Variable-rate seeding especially works well on variable soils, says Sam Becker, a Pioneer dealer with Becker Ag Service in Keystone, Iowa.
“We have a lot of variability — all the way down from hills to river bottoms to fields with 95 [Corn Suitability Rating 2] farms — in our territory,” he says. “Obviously, if you have a flat 95 CSR2 cornfield, you won’t see much change in those [variable-rate] zones. If you have more variable soils, [variable-rate seeding] can make a difference.”
CSR2 measures a soil's productivity from 5 to 100, with higher numbers reflecting better soil quality and yield potential.
Yield potential is the main factor Frazier and his family use to select hybrids and varieties, but not the only one.
“We look at standability and whether it will stand during the next windstorm,” he says. “We don’t want to overload plants in soils where it could tend to go down.”
Solely concentrating on yield can nix profits if factors such as lodged corn result, Frazier adds.
“In the farming world, we always chase yield because it’s an easy and simple number,” he says. “But is it yield or profit? At the end of the day, the farm that's [most] profitable is going to last longer than the farm that yields the most.”