Value of Data: Planning Ahead for Side-Dressing Nitrogen
The crop is about planted here, and I am beginning to plan for side-dressing corn. In our operation we have a target range of total N that we would like to provide the crop. That range is a lbs/ac goal, something like 175-250 lbs/ac. However – probably like your operation – each field has a different yield goal, different amounts of nitrogen pre-applied, and different previous crops with nitrogen credits.
In years past, we would typically pick one rate to side-dress all the corn, but in recent years we have decided that we can use more technology to assist us in making the side-dressing operation more nitrogen efficient. One step towards nitrogen efficiency is making a field list that includes all the nitrogen credits already in each field. For example, some of our fields will have 32%, urea, and fall manure, which would indicate less side-dress nitrogen needs.
Another step we take towards nitrogen efficiency is a two-step process, using the OptRx™ system. We first use the maps made from the OptRx sensor to evaluate the crop. Second, we use the sensor to help apply nitrogen while in the field. In past years I have found that the sensor does a good job predicting corn yield, as you can visually see from the maps to the right. Thus, before we side-dress our corn, we spray our corn with the 2nd pass herbicide (with the OptRx sensor recording maps) and this operation gives a map that gives us an idea of how much stress or lack of stress.
We use these maps as another layer of data to evaluate, getting an idea of how the OptRx system will apply the nitrogen, allowing us to make planned adjustments before the side-dress operation. When we begin side-dressing, we have a determined nitrogen range from our own calculations combined with the OptRx sensor maps, allowing us to set the values to operate within our range.
There are many opinions out there on nitrogen usage; however, a final piece of our nitrogen efficiency program is leveraging our experiences from past years. I encourage you to calculate your nitrogen credits, use maps and scouting to evaluate and then reflect on the yield results. The results you see over a period of years is invaluable to your operation and your confidence level when preparing to apply nitrogen to your crop.