The fact that new corn hybrids require an ever-increasing yield potential, and therefore a growing appetite for nitrogen and other nutrients, is well documented. Recent research appears to indicate that the timing of nitrogen applications may need to shift to get the most from newer corn genetics.
“Some research appears to indicate that post-flowering applications of nitrogen will increase grain fill and grain weight,” says David Lankford, agronomist with Yuma, Colorado, based Agri-Inject. “In fact, one seed company recommends applying at least 30 pounds of nitrogen after pollination is complete.”
Lankford is referring to plot research from Beck’s Hybrids1. In a 2015 two-hybrid trial, Beck’s researchers determined that 30 lbs. of UAN applied through fertigation at VT stage boosted yields by almost 30 bu/A over irrigation alone.
Over the past few years, seed companies and universities have conducted extensive research into nitrogen-use patterns in modern corn hybrids. Both confirmed that 37% of the total nitrogen needed by the corn plant will be taken up during the grain fill period (R1 to R6).
DuPont/Pioneer notes that in high-yield environments, 140 to 210 lbs. of nitrogen per acre is needed to support grain development 2. Only 38% of this need is supplied by remobilizing nitrogen from vegetative tissue. That means the corn plant needs to take up roughly 85 to 130 lbs. of nitrogen from the soil for optimum grain fill.
Agri-Inject is conducting research to determine the impact of late-season nitrogen. “We’re looking at the impact of late-season nitrogen on these hybrids under six pivots this summer,” notes Lankford.
Late application options
Feeding corn plants additional nitrogen as they need it to achieve optimum grain fill and kernel weight makes agronomic sense—particularly with the newer high-yielding hybrids. How to apply that nitrogen most effectively is the question. Ground application equipment cannot travel over tasseled corn. Center pivot owners, however, do have a late-season application option.
“Fertigation can be used very effectively to apply additional nitrogen post flowering,” says Erik Tribelhorn, Agri-Inject CEO. “We do have some customers who have installed center pivots and injection systems specifically for this purpose.”
If you have a center pivot system, are interested in applying late-season nitrogen to your corn but don’t have an injection system, it’s relatively easy to make the move.
“We’ve made our systems simple to set up, calibrate and use,” Tribelhorn states. “Technology has made the transition even easier, and we have resources on our website to help.”
1 Beck’s 2015 Practical Farm Research Results, Pivot Irrigation Study, pg. 32
2 Nitrogen Uptake in Corn, Crop Insights,DuPont/Pioneer,