As slow-release products and split applications become more common in the pursuit of fertilizer efficiency, it’s important to understand the timing of when a crop needs those nutrients to avoid situations where fertilizer that’s been applied is not available when the plants need it.
The agronomy team at Manitoba equipment dealer Enns Brothers is in its fourth year tracking nitrogen uptake and mineralization in wheat fields across the province. The study is based on soil samples taken every two weeks through the growing season, looking at nitrate levels at 0-6″ and 6-24″ depths.
“The biggest surprise to me is the strong nitrogen uptake,” says field advisor and agronomist Dave Ives, in the interview below, discussing the timing of N uptake at the Manitoba 4R Day at Innovation Farms near Grosse Isle, Manitoba earlier this month.
“The four or five leaf stage — we always hear about it, but it’s really surprising to track it and to see the results. It’s more than I had expected. Being an agronomist for 26 years, I didn’t realize that [wheat] needed that much N that quick,” he says, referring to this chart:
The implication of that spike in N demand is there’s a risk of not having enough N during that critical window.
“I think we have to be aware of the products that we’re using, when we apply, to ensure that we’re not sacrificing any yield early on in the season,” he notes.
In addition to uptake, the study is also looking at N mineralization rates in wheat fields later in the season, as soil nitrate levels climb. Ives says they plan look for any significant insights regarding different soil textures and organic matter levels, and summarize the results from the four-year study this upcoming winter.
Check out the interview below for more with Ives on understanding nitrogen uptake and mineralization in wheat from the 4R field day at Innovation Farms: