Field experiments were conducted to measure variation in yield, stalk-N concentration, and the N content of harvested grain, for corn with anhydrous ammonia (NH3) fertilizer. N was applied with the conventional, Vertical-Dam, Rotaflow™, and FD-1200 prototype manifolds with an application rate goal of 84 kg N/ha (75 lb N/ac). Applications were with each outlet on the manifold plumbed to one applicator knife (normal), and with manifold outlets redirected so that some knives received no NH3 while other knives received twice the rate goal (modified). For two years of the study, NH3 was applied and a third year had only the residual of the previous year. Rows were harvested singly to record harvest yield and take a grain sample. Results showed a positive correlation between N application rate and stalk-N concentration for all three years. No correlation between N content of grain and other factors was observed. For one site-year, measured yields between the two application arrangements were significantly different for all manifolds. Small variations in application rate between the normally plumbed manifolds did not result in statistical yield differences.
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