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Study: Late-season N hits sweet spot

By Staff | May 29, 2016

Tyler Steinkamp WinField agronomist for eastern Iowa

SHOREVIEW, Minn. (WinField Solutions) – Farmers now have fresh data to help them get the best return on their nitrogen investments.

Results from the 2015 Answer Plot program by WinField show a positive yield response to split-season and late-season N applications, made at critical corn growth stages.

To help farmers identify the best way to optimize N use by corn, researchers compared the results of three different application scenarios. These are:

  • Applying the total N allotment at planting.
  • Applying two-thirds of the N at planting and one-third at V10.
  • Applying the total amount of N at planting, followed by additional N at VT, or tasseling. Both split applications were made with the 360 Y-DROP applicator for precise placement at the stalk base.

More bushels

When compared to the total N application at planting, trial results showed average yield increases of 9.4 bushels per acre with the split application at planting/V10, and 11.2 bushels per acre with the total N application at planting followed by additional N at VT.

Tyler Steinkamp, WinField’s eastern Iowa agronomist, said this should come as no real surprise, since the option of a shot of N at tasseling is adding more N than the other plots received. But, he added, getting two additional bushels in this manner, may not be worth the extra cost.

By making the second applications at V10 and VT, plants received an N boost during the crucial V10 to R2 growth stage, when corn needs 50 percent of its total nitrogen.

“Our N trial not only demonstrates the importance of feeding the crop at the right time, it also showcases how advanced applicator technology can help get the most benefit from each application,” says Kevin Eye, vice president of WinField’s agronomy and product development. “These results verify how we allocate inputs can have a big impact on bottom-line profits as well as the environmental costs of applying excess N.”

Focused inputs

Other key Answer Plot trial results in 2015 reinforced the value of focusing input investments where they will deliver the greatest returns throughout the farm operation.

“To help farmers weather ongoing low commodity prices,” Eye said, “we continue to focus our research on areas that will help farmers understand that prosperity in today’s market doesn’t necessarily come from spending less.

“It comes from spending smarter. As we evaluate new products and tools, we share objective, data-based insights that can help farmers be successful next season and beyond.”

This includes, Steinkamp said, planting hybrids best suited for the soil profile, not just splitting N applications.

“If I have a hybrid that is responsive to nitrogen,” Steinkamp said, “I’m going to be putting it on good soils and giving it additional N.”

Plant tissue sampling will also help the grower determine what nutrients and how much of them the plant is taking up, Steinkamp said. This is essential, he said, to keep the flow of nutrients coming from the soil, rather than the plant cannibalizing lower leaves and moving nutrients farther up the plant.

“Once it starts to cannibalize, that’s it.,” Steinkamp said. “It’s a process that’s very hard to stop.”

In addition, he said, growers still have to consider the overall weather conditions of the growing season when decideing to add additional nutrients to a growing crop.

If the weather has been drier-than-normal, there will be more nitrogen present than if it has been normal or wetter-than-normal.

He also recommends adding 10 percent sulfur to the fertilizer mix.

“Sulphur and nitrogen are tied closely together,” Steinkamp said.

Sulphate behaves like nitrate in the soil. In the plant, nitrogen and sulphur are both essential building blocks for proteins. Sulphur deficiency will severely reduce the efficient use of nitrogen and limit protein synthesis.

Additional info

From the Answer Plot projects, researchers said they learned:

A). Response to fungicide scores pinpoint yield advantages from fungicide applications.

Trials including 112 hybrids showed that RTF scores accurately predict the effectiveness of fungicide treatments, helping farmers determine when applications are economically beneficial.

B). Soybean seed blends provide optimal performance in diverse environments. In regional Answer Plot trials, soybean seed blends (WinPak varieties) consistently outperformed their individual component varieties across three maturity groups.

C). Timely applications of copper consistently improve wheat yield.Yield response to 10-34-0 plus MAX-IN Copper foliar application at the 4- to 5-leaf stage was 5.4 bushels greater than with 10-34-0 alone.

D). Sound trial data projects hybrid performance in local environments.Farmers can be confident that a hybrid will perform as expected when they use a data-based tool like the WinField CHT Tool (a component of the R7 Tool) to choose seed based solely on its genetic benefits.

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