How much nitrogen does it take to produce 200 bushels of corn per acre? That’s a very common question with multiple answers. There is no one-size-fits-all approach to nitrogen management. And not every corn crop needs the same amount of N to produce 200 plus bushels per acre. The reality is t hat an effective nitrogen management plan needs to focus on how much N a particular field and corn crop needs, as well as how to properly manage N throughout the growing season — with adjustments along the way.
“Inputs must be managed differently today, as margins shrink and regulatory concerns grow,” said Ron Lloyd, Agronomy and Technical Lead, 360 Yield Center. “Now is the time to take control and make even smarter N management plans that focus on applying N when and where corn needs it most.”
Lloyd offers five steps to rethinking — and maximizing — nitrogen management.
Know, Don’t Guess how much N is Left
“As farmers, we often take the gut-feel approach to crop management,” Lloyd added. “Sometimes that works.” But guessing how much N is in a field — and, in turn, guessing how much to put down — doesn’t allow for the most accurate and impactful nitrogen management plans. Nitrogen levels are complicated to calculate on gut- feel alone. Rain events, soil moisture, pH, microbial activity and mineralization all play a role. The only way to know exactly much N is needed is knowing how much is in the field.
Fortunately, today farmers can know, in real time, N levels in their fields, with portable soil testing systems that provides in-field soil nitrate results in about 5 minutes. They can also can generate GPS-tagged, zone-specific readings with comparable accuracy to commercial labs.
Don’t Assume a One-and-Done Approach will do
Corn demands nitrogen throughout the growing season, and its demands fluctuate and continue to grow as the season progresses. In fact, up to 75% of N is used after V10.1 With too little nitrogen late in the growing season, especially when kernels form, yield potential could be at risk.
Split-nitrogen application allows farmers to apply N throughout the growing season. It’s not about starving the crop early by holding N back for late-season application or putting down all of the N early and never coming back. It’s about maximizing N inputs so it’s available when the corn needs it.
Outsmart Mother Nature
Even with a split-N approach, farmers might not be making the most of their nitrogen. Mother Nature throws some curve balls — like big rain events that can reduce available N. At the same time, that extra moisture can raise yield potential. Crop modeling software can allow farmers to take control and adjust nitrogen management plans based on weather events midseason.
Now, farmers can anticipate the potential for big rain totals in June and push N application back, if needed, so it’s not at risk to Mother Nature. Because nitrogen management plans should be monitored and adjusted throughout the season based on full-season, real-time data.
Provide the Right Amount of N in the Right Place
Nitrogen needs change not only throughout the season but also throughout fields. Different management zones in fields use nitrogen differently — a 3.5 inch rain on a hill makes a different impact on N levels than a 3.5 inch rain in a valley. Taking nitrate samples from different management zones allows farmers to build a variable rate N plan that provides the right amount of N to each zone in a field to maximize every pound of N.
Where N is applied within the row also is important. Traditional sidedress methods apply N in the middle of the crop row — nearly 15 inches from the stalk base. Yet, a corn plant acquires more than 60% of its N from a horizontal radius of approximately 7 inches. There are tools farmers can apply N within 2 to 3 inches of the stalk base — that means nearly 80% of the plants root mass is within the targeted application zone. And with the funneling nature of a corn plant, farmers can take advantage of stem water to move N placed at the base into the root zone — putting nitrogen in the right place for uptake and minimal loss.
Rethink your Window of Application
Some farmers may avoid split-N application because of the worry, “Will I miss my window?” Traditional sidedress methods tend to have a short and worrisome window of application. And, if farmers miss it, their crop goes without the N it so desperately needs.
Now, farmers don’t have to worry. Tools can extend the window of application, with designs that allow for more flexibility in timing for late-season N application — so farmers can apply N when crops needs it most, whether that’s at V6 or all the way up to tassel. That is more than 30 days of application time. So now farmers don’t have to worry and have the control to hold some N back for a late-season application.
The days of luxury nitrogen application are over. With smarter N management, farmers can make the most of inputs by applying N when it’s needed most, instead of putting it out early when it’s vulnerable to loss from rain and environment.
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