MAIZE PRODUCTIVITY AS A RESULT OF APPLICATION OF CONTROLLED AND SLOW RELEASE UREA

Nitrogen (N) is the main limiting nutrient for productivity and yield components of maize crop. Urea is the main nitrogen source used, which, despite the high N concentration (45%), presents many losses through leaching and volatilization. In view of that, the purpose of the experiment was to evaluate the effect of applying N doses with urease inhibitor, nitrification inhibitor and slow-release urea, in relation to the conventional urea, on productivity and yield components of maize crop. The experiment was conducted in the municipality of Santa Rosa do Sul, state of Santa Catarina, in a 4x5 factorial scheme, where factor A corresponded to four nitrogen protection mechanisms (urea with urease inhibitor, urea with nitrification inhibitor, slow-release urea and conventional urea) and factor B corresponded to the surface-applied nitrogen percentage for the aforementioned protection mechanisms (0%, 25%, 50%, 75% and 100%). Under the edaphoclimatic conditions of the present study, fertilizers with inhibitors (nitrification and urease) and with slow release do not significantly increase maize productivity in relation to the conventional urea and, regardless of the source used, it is possible to reduce the recommended dose by 25%, based on soil analysis, without significantly impacting maize productivity.