Crops News

Verdesian: Wet or dry, nitrogen loss is inevitable


Applying the nitrogen (N) your corn crop needs can be challenging, rain or shine. The weather is often the first condition in preventing farmers from getting into the field to make pre-plant, topdress, or sidedress applications.

“Ideal conditions to apply N would be spoon feeding it during the growing season, just before the plant needs it,” says Ben Hushon, general manager of The Mill, which provides custom blending of liquid or dry fertilizers as well as custom application services to farmers in six counties along the Maryland and Pennsylvania line. “Because it’s ideal to apply N when the plant needs it, we support split applications, following a pre-plant application with one or two applications during the growing season. Sometimes this can cause challenges. If weather prevents you from making the last application, your crop is left short of the N it needs.”

Farmers should make sidedress and topdress N applications at about the V6 to V8 growth stages, before the canopy closes in most of the Corn Belt, says Darin Lickfeldt, Ph.D., senior technical development manager for Verdesian Life Sciences. After farmers apply their N, it can be at risk for loss in both wet and dry conditions.

“Farmers should take steps to protect their applied N from loss to the environment,” says Lickfeldt. “If it ends up being dry, farmers could lose their applied N to volatilization; if it ends up wet, you could lose N to denitrification; and if you have water moving through the soil, you could lose N to leaching.”

Much of the Corn Belt is still dealing with saturated and wet conditions this spring, with higher than normal rainfall up to 300 percent above the monthly average in some parts of the Midwest, according to the National Weather Service, leading to concerns about pre-plant N applications being susceptible to loss via denitrification or leaching. Kansas, Oklahoma, Missouri, Illinois, Michigan, and Wisconsin are among the states most affected by saturated soils and high moisture levels.

“In high moisture conditions, you certainly have higher chances of the applied N getting diluted and potentially moving into the environment with the water,” says Hushon.

Even if farmers have favorable conditions and are able to apply their N, that doesn’t mean there’s no danger of loss. For example, farmers could apply in-season N and, if the weather turns dry, that applied N can be susceptible to loss via volatilization.

“If you apply untreated N and there is a prolonged period of two or three weeks with less than a half inch of rain, you can lose up to 25 percent to 50 percent of your applied N to volatilization,” says Hushon. “Soil type and soil moisture play a role in susceptibility to volatilization, and the form of N matters, as urea is more volatile than liquid urea ammonium nitrate (UAN), and ammonium sulfate is extremely stable.”

Even when farmers follow the 4Rs of Nutrient Stewardship, conditions conducive to N loss may occur, and farmers may need to include a nitrogen fertilizer manager or stabilizer. Hushon says it takes a premium product to protect N from all three forms of loss, which is why The Mill uses NutriSphere-N Nitrogen Fertilizer Manager from Verdesian. Hushon says when farmers started paying more attention to yield monitors, they could tell right up to the individual row if they ran out of NutriSphere-N while applying N. But, says Hushon, increased performance is not the only benefit to his farmers.

“We have proven through both on-farm and replicated trials that we can reduce the amount of N we put down on corn and get as good or better yield results,” says Hushon. “To be able to tell a farmer in the Chesapeake Bay area that 180 units of N can provide just as good, and possibly better, results than 200 units and reduce the environmental impact is a big deal in this neighborhood.”

Over 500 trials have been conducted on NutriSphere-N use on corn and have shown more than a 90 percent positive yield response over the control. NutriSphere-N Nitrogen Fertilizer Manager has been commercialized for more than 10 years and has been used on more than 46 million acres. The product is available in formulations that can be used on granular urea, liquid UAN, and anhydrous ammonia.

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