Dave Franzen, North Dakota State University Extension soil specialist, says an on-the-go, in-season nitrogen sensing system tailored to the Northern Plains may soon be available to use when sidedressing corn.
The system uses optical sensors to read the color of corn leaves. Franzen and others are working on an algorithm -- a set of step by step calculations -- that will accurately convert the leaf color to the amount of nitrogen in the plant and then to the amount of N that needs to be applied to make up any shortage.
The onboard computer doing to the calculations will feed the rate information to a controller on the applicator which would vary the amount of N being applied. Areas that were short of N would be get additional fertilizer. Areas that already had enough N wouldn't get anymore.
On-the-go, in-season N sensing the next thing in precision ag, according to Franzen.
Creating management zones helped even out the variability in field. On-the-go sensing and variable rate sidedressing will help even out the variability within management zones, he says.
The project is tied to the work NDSU soil scientists are doing to revise corn fertilizer recommendations. Another year of field work is scheduled in 2013 and new recommendations will like announced for the 2014 or 2015 season. There will likely be different recommendations for western and eastern North Dakota, for no-till and conventional till corn and even for different soil types, Franzen says.