Making the most of in-season nitrogen applications
"To determine which approach is best for a particular farming operation, growers should carefully consider the pros and cons of each approach, likely using a combination of strategies to maximize potential profit while minimizing risk," Shanahan says.
Nitrogen Application/Management Tips
To meet nitrogen level needs while avoiding weather-related pitfalls, growers can spread risk by applying nitrogen at multiple times. Nitrogen may be applied in the fall, early spring (preplant), at planting and in-season (sidedress).
"The ideal circumstances are to do a split application," Shanahan says.
This time of year - in-season - nitrogen applications allow for adjustments to planned nitrogen supply based on weather variations.
If wet spring conditions result in nitrogen losses, sidedress rates can be increased. If warm temperatures and moderate rainfall results in high nitrogen mineralization and an N-sufficient crop, sidedress rates can be reduced. (Determining these needs can be done using the evaluation tools noted above.)
In-season nitrogen applications can supply nitrogen to the crop near the time of maximum plant uptake. However, if wet conditions develop, sidedress applications may be delayed beyond the optimum application date. Very dry conditions can result in a delay in availability of sidedressed nitrogen to the plant.
Because of the risks associated with in-season nitrogen application, the practice should be managed carefully. Soil fertility specialists often recommend only one-third of total crop supply be targeted for sidedress application. In addition, growers should be prepared to apply sidedress nitrogen as quickly as possible when the window of opportunity appears. Finally, a backup plan should be in place for in-season application to help avert significant nitrogen deficiency and yield loss in case of weather issues.
"To make the most of nitrogen applications, growers need to evaluate the type of equipment and nitrogen sources available," Shanahan says. "They also need to assess the weather and adjust based on conditions to ensure an nitrogen strategy that delivers."
To help you evaluate your nitrogen needs and choices, consult your area Pioneer agronomist or university Extension resources for assistance, or visit the agronomy section of Pioneer.com.