Protect Fall Nitrogen Applications to Optimize Yield in 2011

INDIANAPOLIS — Sept. 28, 2010 — Good to excessive moisture across much of the Corn Belt, followed by the telltale signs of nitrogen deficiency, provides an excellent reminder about just how critical nitrogen is in corn production and may help explain why this year’s yields failed to meet expectations for some corn farmers.

            “When dealing with a mobile nutrient like nitrogen, moisture will have a great deal of impact on what happens throughout the season,” says Sam Ferguson, field scientist with Dow AgroSciences. “Early yellowing of corn leaves this season told us nitrogen programs that would keep the corn well-supplied with nitrogen up through the grain fill period in a normal year were not as effective this year.”

            But that doesn’t mean growers should consider fall a time to replenish nitrogen levels by applying additional nitrogen.

            “Nitrogen isn’t a nutrient one can deposit in the soil and withdraw when needed, like a bank account,” Ferguson explains. “With nitrogen, we have the opportunity to reset the game every year.”

            He says attempting to replace lost nitrogen simply loads up the system and leads to additional nitrogen losses and unnecessary expense. A better approach, Ferguson says, is to develop a plan for the next growing season. Making nitrogen stabilization a part of that plan can help reduce nitrogen lost to leaching and denitrification and ensure more nitrogen remains available to the corn plant during key growth stages next year.

            He says now is an excellent time for growers to evaluate their fertility programs and make adjustments for this fall’s fertilization season. As a starting point, he reminds growers that nitrogen losses from fall-applied manure or anhydrous ammonia typically don’t happen during the fall or winter due to low soil temperatures, but instead occur during spring rains. This year’s early yellowing observations likely indicate premature nitrogen loss during an especially wet start to the growing season.

“Think about what went right and what went wrong during 2010, and how you can improve your chances of success next year,” Ferguson advises.

The addition of a nitrogen stabilizer this fall, whether applying anhydrous ammonia or liquid manure, can be a big step in the right direction.

“Regardless of the fertilizer source, growers dedicate a great deal of resources — time, money, effort and hope — into the application process, and they need to be sure it will pay off.”

            Nitrapyrin, the active ingredient in Instinct and N-Serve® nitrogen stabilizers, helps keep nitrogen at the root zone and available to the corn plant when it’s needed most. These are the only nitrogen stabilizers labeled by the U.S. Environmental Protection Agency (EPA).

Year-round benefits

            Nitrogen stabilized with Instinct or N-Serve has helped to increase yields an average of 7 percent with fall-applied nitrogen and 5 percent with spring-applied nitrogen. Ferguson says that all anhydrous applications, whether fall-applied, spring preplant or sidedress, should be stabilized with N-Serve at the recommended label rates (see Table 1). N-Serve is the only nitrogen stabilizer proven to optimize yield potential when used with anhydrous.

            Introduced in 2009, Instinct is an encapsulated form of nitrapyrin, and was specifically designed for use with liquid manure, UAN and dry fertilizer blends, protecting nitrogen just as N-Serve does with anhydrous. (See Table 2 for treatment recommendations.)