Three companies now make and sell sensors designed to mount on a high-clearance sprayer or other application rig so that you can determine how much nitrogen should be applied to corn on the go. The theory is that if the sensors can detect how much N is needed and send a message to the rate controller, the proper amount can be applied for that crop in that part of the field.
It's more than theory since it's on the market, and some people are using it. However, one farmer who intended to try it out last year, and who purchased the application equipment and sensors to make a late-season final application of N, based on these sensors, simply ran into too many other things to do in late June, due to weather delays, such as spraying soybeans. That's been one hang-up- timing the operation so that it fits into the farm system.
Bob Nielsen and Jim Camberato have been looking at these sensors and trying to determine if they work for several years. Nielsen is convinced the concept is sound. What remains to be proven is whether a farmer can run over a field with the device soon enough in the season to use the sensor, yet not be so late with his sidedressing application that he's already lost yield.
That scenario, of course, would assume he's going to apply all of his sidedress N, the majority of what he's applying for the year, in the sensor application. The other possibility is to come back with the sensor after applying what should be enough N, when high-clearance equipment is needed, and seeing if the crop needs a bit more N in places.
What they really need, Nielsen says, is more definitive research. And they do have research underway. The trick is that to do it in a scientific way so they can prove it, it's not easy research to set up. There are multiple variables that must be accounted for. One variable that can't be anticipated in advance is what Mother Nature will do in any one season, and how rainfall patterns will play into application plans.
For now, it's still promising technology, and if you've purchased it and figured out how to use it, Nielsen would like to know. He's willing to learn from anyone who has the edge on smoothing out the details to make this technology take off.