Helping Growers to Demo Nitrogen Sensors.

Nitrogen is expensive, but when crops need it the payoff is big. How can growers make decisions about how much N to apply, and where? Crop sensors are an exciting new tool that make it possible to diagnose crop N status and apply the correct N rate while driving through the field. One disadvantage is that the sensors represent a sizable investment with a steep learning curve. Through an innovative ‘demo’ program, we have helped corn growers with trying the sensors in their fields without having to make a big up-front investment of time and money. We have mounted ‘loaner’ crop sensors on grower and retailer equipment and guided them through the process of using the sensors. Over the past four years, we have used the sensors in 61 corn fields in Missouri. In many of these fields, we install side-by-side strips of the producer’s normal N rate and sensor-guided variable rate N. Averaged over 41 demo fields with good side-by-side comparisons, the sensors have reduced N rate by 23 lb N/acre with no effect on corn yield. Growers can see the correlation between the N rates on the monitor and the appearance of the crop. We plan to expand this program to include cotton growers in 2008. Several growers are in the process of adopting sensor-guided sidedressing with our help.