Greg Kneubuhler pulled up in front of about 60 replicated nitrogen plots his company, G & K Concepts, helped clients put out this year. Because the plot design is so simple and the nitrogen is sidedressed, the plots don't take a lot of extra time for farmers to plant or harvest. However, the results should help build an accurate data base for true nitrogen rates, says the consultant, who lives near Harlan, Ind.
Moisture levels were nearing harvestable levels last week when we visited the plot. A short trip along the path cut into the plot to make observations easier made it obvious that differences between plots where different N rates were applied were still obvious.
Plots that received only 100 pounds per acre were characterized by somewhat shorter plants. Some tops were falling out. Kneubuhler says what the appearance told him was that the stalks had cannibalized themselves somewhat to make as much corn as possible. Dave Nanda, Corn Illustrated consultant for Farm Progress Companies, says that's true, but the plant does it because it wants to produce as many viable progeny as possible, not because it cared how full your grain tank is after running the corn.
The ears were also visibly shorter in the plots with 100 pounds of nitrogen. Then Kneubuheler stepped into a plot on the other end of the spectrum, where 250 pounds per acre was applied. These rates include all sources of commercial nitrogen applied on the plot. It does not include taking a credit for bean stubble left after the previous year.
Stalks still had a tinge of green, and were taller and still tougher, being more resistant to the touch. Obviously, less cannibalization of stalks had occurred. Ears were alos longer, and in most cases, typically filled to the tip.
In between these two extremes the consultant found plots that received 150 pounds of N per acre. The visual results lined up with expectations. Ears were medium length, with more aborted kernels near the tip of the ear than in plots that received 250 pounds of N per acre. Stalks were brown and appeared dead, but were still standing.
"We are definitely going to find differences when we harvest plots this year," Kneubuhler says. "Plots are actually harvested by the farmers. Having a yield monitor is one of the requirements for being allowed into the plot program.