Substantial yield bumps from new nitrogen-efficient hybrids should come towards the end of this decade and early in the next one, says Michael Clements, Monsanto corn intrinsic yield and nitrogen lead.
No one is talking the elimination of applied nitrogen, or a huge bump in yield per unit of nitrogen applied. At least not for another several decades.
"Genetic gains continue to improve a couple of bushels a year, regardless of company," he says. “Marker-assisted breeding, biotechnology, chemistry and agronomic advances, all mixed in, will drive more yield per acre per unit of nitrogen."
Nitrogen-use efficiency is actually entwined with water-use efficiency, says Dave Warner, program leader, ag biotech, DuPont Pioneer. The better the plant is able to adapt to periodic stress periods, the more stable it is, and the more efficient it will be utilizing water, nitrogen and other nutrients, he says.
"There is still a lot of untapped native variation for nitrogen-use efficiency within our own germplasm," Warner says. " DuPont Pioneer has identified many lead genes involved in nitrogen uptake, storage, mobilization and remobilization within the plant."
He and Clements note the ability in advanced greenhouse and field plots to create managed-stress situations by removing nitrogen and then applying controlled amounts to see how the genes react under various situations. Germplasm best able to handle nitrogen stress at different stages has the best ability to yield in the widest range of conditions.
A new facility at the Donald Danforth Plant Science Center, St. Louis, Mo., may dramatically speed an understanding of how genes handle such stress. The Bellwether Foundation Phenotyping Facility combines controlled plant-growth environments with three imaging chambers and a conveyer to move volumes of plants from one to the next. The chambers measure real-time growth rate, photosynthetic activity and water and nutrient utilization.
"We can collect images on a thousand plants a day, identifying subtle variations in key traits," explains Tom Brutnell, director of the Center’s Enterprise Institute for Renewable Fuels. “And, importantly, we can map the genetic variation to identify the genes.”
"If we find a new master pathway, it lets us better understand how the plant processes nitrogen," explains Brutnell. "We've had contact with a number of seed companies that see the value in conducting such screens."
No silver bullet for nitrogen utilization
Doug Albin, Clarkfield, Minn., isn't waiting for a silver bullet in nitrogen utilization years from now, much less in decades. A member of the Minnesota Corn Growers Research and Promotion Council, he’s concerned that environmental pressure may produce overly restrictive regulations.
"If we have regulations that say you can only apply this much in this place, what happens if you get a 6-inch rain and lose your nitrogen?" Albin asks.
He and his wife Lois grow corn and soybeans on 1,200 acres along the Yellow Medicine River. An advocate of right product, right rate, right time and right place, he has eliminated fall application in some fields and spring applications in fields that tend to flood. He uses variable-rate and split-rate applications, as well as tissue testing and nitrification inhibitors to spoon-feed his corn.
"Yield per pound of nitrogen applied has continued to increase over my 35 years of farming," says Albin. "Seed companies like to claim credit, but I feel it is largely due to better targeting nitrogen with equipment and technology. The difference between applying nitrogen and applying the right amount of nitrogen is a big difference in N."