EVALUATION OF NITRIFICATION INHIBITORS FOR NO-TILL CORN

Abstract

Increased N loss from leaching, denitrification or volatilization with reduced or no-till farming may offset potential energy savings from reduced field operations. Nitrification inhibitors have effectively reduced N losses in conventional tillage and may increase the energy efficiency and yield resulting from N applied to no-till corn. For 3 yr, corn produced by no-till farming was studied to determine the effects of inhibiting nitrification of spring-applied N with nitrapyrin or etradiazole on corn yield and N use efficiency. Low grain yields obtained without N fertilization indicated that only low levels of residual or mineralizable N were available for corn growth. The importance of incorporating N in the soil was indicated, because plants fertilized with 28 percent N solution injected into soil produced 20% more grain than plants fertilized with broadcast 28% N or urea. The highest grain yield was achieved with anhydrous NH3. Plants fertilized with surface-applied N fertilizers showed symptoms of N deficiency by 30 days postpollination. Inhibiting nitrification of injected NH3 or 28% N solution generally increased corn yields compared with N without the inhibitor. Nitrification inhibitors have a good potential to improve N use efficiency and grain yields by reducing losses of applied ammoniacal N in no-till corn production systems.