Sidedress Applications Provide Corn N When It’s Most Needed

Farmers who applied lower pre-plant rates of N or lost some N to the environment can adjust with a sidedress

Cary, N.C. (May 31, 2017)

This year, much of the Corn Belt was pelted with as much as seven to 10 inches of rain in 10 days, so if a farmer applied 100 percent of his or her nitrogen (N) in a pre-plant application, he or she has likely lost a great deal of N to the environment. But farmers can adjust their N plans and apply more N in a sidedress application to make up for any applied pre-plant N that may have been lost to the environment. A sidedress application can ensure corn gets the N it needs, when it needs it most.

Corn takes up about 70 percent of its N between the V4 to R1 growth stages. From the V8 leaf stage through tasseling, N uptake is about four to eight pounds per day. Most sidedress applications occur at the V6 to V8 growth stages, which occurs in early June in much of the Corn Belt. This allows a standard spray rig to safely make a pass through the field without damaging corn stalks, and provides that N just before the corn begins its rapid uptake. This timing minimizes the time N sits in the field and is susceptible to loss to the environment. However, that doesn’t mean that the N applied as a sidedress isn’t at risk to environmental loss.

“We did a lot of research seven to 10 years ago, and we found that there’s actually a higher percentage of N lost to the environment through volatilization, denitrification and leaching during that sidedress application than in a pre-plant application, which was kind of an eye-opener,” says Dave Schwartz, executive vice president of sales and plant nutrition for Verdesian Life Sciences. “Protecting the N in a sidedress application provides a very viable return on investment (ROI) for farmers.”

Weather is the determining factor when it comes to N loss, with N being susceptible to leaching when there is water moving through the soil, denitrification under saturated conditions, and volatilization under hot and dry conditions. Farmers cannot predict the weather, and would be wise to protect their N investment, says Darin Lickfeldt, Ph.D, senior technical development manager for Verdesian.

“Farmers risk losing their investment in N, not receiving the benefits to their corn crop and not maximizing their yield,” says Lickfeldt. “It takes about 1 lb. of N per acre to produce about 1 Bu./A of grain, so if you lose 10 lbs. of N to the environment, that’s 10 lbs. not making grain. Farmers are paid based on how much grain they produce, so protecting every lb. of N should result in another Bu./A of corn yield.”

So, if the price of corn is $3.50 per bushel, and you can add 10 Bu./A by decreasing N loss with NutriSphere-N® Fertilizer Manager, that’s $35 more per acre, which provides a return on investment of 2.8 to 3.8 to 1. For every dollar spent on NutriSphere-N, the grower could get back $2.80 - $3.80. More than 400 trials over a period of 11 years show that NutriSphere-N provides that 10 Bu./A yield increase and there was a positive yield enhancement 90 percent of the time.

“Over the years we’ve done a lot of trial work, and we’re seeing about a 10 to 12 Bu./A average increase over all years. However, in extreme situations, you can see as much as 30 to 40 Bu./A increases,” says Schwartz, who also farms in Guthrie Center, Iowa. “When you factor in the water quality element of losing 30 to 50 percent of applied N going out the tile line, NutriSphere-N offers one of the best returns on investment a farmer can make.”

One reason NutriSphere-N provides that ROI is because it protects N from loss caused by volatilization, leaching and denitrification, a distinct advantage over competitive products that protect against only one or two forms of loss. NutriSphere-N is available in several different formulations that can be used on urea, urea ammonium nitrate (UAN) and anhydrous ammonia (NH3), ammonium sulfate and aqua ammonia, and each form of N presents its own challenges regarding loss to the environment.

Urea can very quickly volatilize by way of the urease enzyme that causes gaseous loss of ammonia, so if you surface apply a lot of urea, it will be susceptible to volatilization loss, says Lickfeldt. NutriSphere-N quick dry orange (QDO) or granular formulations are available for farmers applying urea. UAN is usually surface applied, but because it is a liquid it generally moves down into the soil an inch or two more easily than urea. However, UAN is still susceptible to loss, and NutriSphere-N liquid or NutriSphere-N HV® for High Volume UAN Applications,are available for UAN. While most of the sidedress applications are made with urea or UAN, some farmers may inject anhydrous ammonia nine to 12 inches deep into the soil profile with NutriSphere-NH3, making N less susceptible to loss, provided it is injected correctly.

In addition to protecting N from loss, farmers can also follow the 4Rs of Nutrient Stewardship to ensure their sidedress applications are as precise and efficient as possible.  The 4Rs call for applying the right source, right rate at the right time and in the right place. Lickfeldt recommends using a liquid fertilizer protected with NutriSphere-N, with about 25 percent to 50 percent of your total N applied in a sidedress at V6 to V8 growth stage and banded close to the row.

“We like sidedress applications within three to six inches of the row,” says Lickfeldt. “If you’re going to band it right on the row you can surface apply it, but if you are applying it between two rows, usually about 15 inches from the row, we like it knifed in one to two inches deep.”

New technologies have made more precise placement of sidedressed N easier for farmers. 360 Y-Drop® from 360 Yield Center features a Y-shaped drop tube, allowing farmers to put liquid N closer to the base of the plant, says Schwartz.

“Some of the new technologies, like Y-Drops, make UAN use in a sidedress more efficient, but it’s all about getting the N on the acres at the right time, no matter what form of N you are using,” says Schwartz. “Having the proper amount of N going into the time of highest N uptake is critical. Hitting that window is something that can be very challenging. We’ve learned a lot over the past 10 to 15 years about managing N. Putting on split N applications is a best practice, and protecting it with NutriSphere-N takes it to the highest level, where all growers need to go to maximize their investment in their crop and protect the environment.”