University of MN Sidedress Timing and Placement Article

There has been a lot of talk in recent years about when the best time of the growing season is to sidedress, such as early growth stages of corn (V3-V8) vs. later in the growing season (V10+ with high clearance equipment). There has also been much more discussion about placement of nitrogen when sidedressing, such as placing N on top of the ground right next to the row or injecting N in the ground closer to the middle of the row.

At FAST, we feel it is important to rely on independent research when working to determine preferred application methods. We included some relevant quotes from an article published by the University of Minnesota Extension in June 2018 below speaking to both sidedress timing and placement. See full article here:

Now (early June) is a good time to do a sidedress application. Research shows that there is little or no benefit waiting to apply nitrogen much past the V8 development stage. In fact, depending on the year, it can reduce yields. Some of our studies have shown that with split applications, delaying sidedress to V12 reduced yields compared to sidedress at V8.

For sidedress applications many worry that nitrogen needs to be applied in some specific way to make sure it is close to the crop roots. The reality is that the corn crop has a massive growing root system, so regardless of placement, the roots will find nitrogen. Nitrogen also moves with the flow of soil water as it is being suctioned by crop roots. So as long as there is water, which is typically not a problem this time of year, the nitrogen you apply at sidedress will find its way into the crop.

If you prefer an injection application, the middle of the inter-row space (15 inches from the row in 30 inch row spacing) works well. At this point in the growing season, corn roots are reaching the middle of the inter-row. Injecting nitrogen closer to the row can result in unnecessary root damage.

FAST applicators allow growers to inject UAN (liquid 28%/32% nitrogen) in the ground early in the sidedress season just before ear girth is determined around V6. By injecting nitrogen in the ground rather than dribbling it on top, growers do not need to rely on a timely rainfall within a couple days following application to secure their nitrogen investment.

Invest in your operation and minimize the risk of your nitrogen applications by injecting your N in the ground early in the growing season with a FAST applicator!